DE3225882A1 - Colour copying method using a stored mask determined by scanning - Google Patents

Abstract

A colour contact copier for opaque image receivers (26) has a scanning light source and an automatic control system for contrast matching and for the exposure intensity. The colour original (25) is scanned in advance in order to determine the initial exposure intensity and contrast matching limits to be expected for the opaque image receiver (26) and to set the necessary automatic exposure and contrast matching signals. The colour original (25) is further scanned in order to generate signals which represent an unsharp luminous mask for contrast control and are stored in a memory (35) such as an image storing tube. The opaque image receiver (26) is brought into close contact with the colour original (25) for the actual exposure scanning; in this process, the unsharp luminous mask is electronically superimposed on the scanning light source in order to obtain an automatic control of contrast and exposure of the image during the copying process. The exposure time for the exposure scanning is shortened even in the case of the use of insensitive reproduction material by means of combined modulation of intensity and speed. <IMAGE>

Description

Color copying process with one by scanning

determined, stored mask The invention relates to a color contact copier for exposing an image receiver by means of a point-shaped scanning light beam starting from an image carrier, the image receiver for at least one spectral component of the scanning light beam is essentially opaque, according to patent ... (patent application P 32 04 581.6), and a method for automatically changing the exposure level and the contrast adjustment limits in a color contact copier with an opaque one photographic image receiver according to patent .. (patent application 32 04 581.6).

Usually, in photographic copying processes, attempts are made to to duplicate the object contained in the original as faithfully as possible. Copier with scanning by cathode ray tubes to change the image contrast a blurred glow mask during the exposure during reproduction are widespread.

A scanning light point is used because the beam intensity of the Cathode ray tube easily for instant contrast adjustment at any point within the copy format can be changed. However, such copiers are not yet widely used for color copying because of such Source available light intensity insufficient for photographic reproductions obtainable in economically justifiable exposure times. A color copier with e.g.

Cathode ray tubes and a standard cover mask would go up to 80E lose its electron beam power in the cover mask, so that a maximum of 20% of which can be converted into light that can be used for the color exposure process. To now requires making a color reversal copy with cathode ray tubes Mixed phosphor as a light source for relatively insensitive duplicating material Exposure times from 5 to 30 minutes depending on the optical density the color template, which is incompatible with most requirements.

A known color copier (US-PS 4,263,001), which is not after Contact method works, particularly concerns the duplication of small slides with a single-lens reflex camera, in which probably modern camera films for the Making duplicates are used. To scan the original, a Video camera and a single cathode ray tube with cover mask for exposure used.

The US-PS 4,263,001 represents the important functions by a block with the designation "Electronic image modification", without describing in more detail, in which way affects contrast or exposure level in the color copier will.

In another known color copier (US Pat. No. 4,145,709) a Vidicon camera tube for reading the originals and for the subsequent exposure a separate and different scanning light point is used at a different location.

In copiers it is a combined intensity and speed modulation known for d5 exposure (DE-OS 30 10 945). Another way to autnmatic Contrast control in a copier with cathode ray tubes is known (US-PS 3 400 632) and works with either intensity or speed modulation. A combined system in which intensity and speed modulation are simultaneously come to use, but is not disclosed.

The use of memory in the context of video signals is known; such as the use of a single scan line memory and telecine (U.S. Patent 4,191,972) and a memory in a photographic copier having a Video camera for recording the electronic image of an optically projected one Originals (U.S. Patent 3,961,366). In doing so, the optically projected original is during superimposed on a projected video image during copying.

There are systems for evaluating a to be photographed or to reproducing original and comparing the original with a predetermined one Parameters known before copying. This is the reflectivity (the exposure level) of the original to be copied evaluated (US-PS 4,160,596) or the negative, the Contains snow or beach scenes.

In neither of the two systems is a scanning light point for change the contrast of the copy is used or the change in the image contrast limits considered for the image recipient.

The conversion of an electronic mask into digital form and their Storage for subsequent manipulation is known (US Pat. No. 4,231,069). These Device is intended for use in systems for combining video images, but not for a scanning contact copier. Also the conversion of analog Video signals in digital form is known in principle (US-PS 4,184,151) if not even for use in photocopying.

Film-to-video conversion devices using a scanning light point for the production of a video signal from a film original are known (US-PS 3 770,882,3851,094; D 344 203).

Other types of contrast modifiers are in photocopiers known as general prior art (U.S. Patents 3,926,520; 3,934,081).

A known device for photographic image evaluation works with laser beams to scan and compose the image (U.S. Patent 3,571,493). It uses feedback signals derived from a mirror beam splitter, to modulate the laser beam and thereby increase the projected image contrast steer. Apparently it is more of an image display device with font contrast control aimed at a copier with contrast control.

An object of the present invention is to provide a novel Color contact copier of the type mentioned with automatic electronic Contrast adjustment and exposure control for use with spectrally opaque, to create insensitive color duplicating materials.

Another object of the present invention is to provide a Three color cathode ray tube light source for photocopying to create the minimum emits an order of magnitude more light than a conventional one with a mixed phosphor or a cover mask working cathode ray tube available stands.

Another object of the present invention is to by Pre-scanning to provide an electronic evaluation of the slide, even if it is missing or only partial contrast adjustment, precise control of the overall exposure level to reach. The electronic evaluation by prescan not only determines the required exposure intensity, but also the contrast adjustment limits the color template to be duplicated for the copying process.

Another object of the present invention is to the density difference or contrast adjustment limits of the original photograph to match or compare with the contrast properties of the image recipient and automatically adjust the contrast of the image during the copying process so that that the original is safely within the contrast limits (i.e. the permissible brightness range) of the image receiver is faithfully reproduced.

Yet another object of the present invention is to a device with a combined intensity and speed modulation to create contrast adjustment, the significantly greater flexibility in brightness and contrast adjustment than when using intensity or speed modulation is available alone.

An additional object of the present invention is to To create a color contact copier, especially for copying on opaque Image receiver is suitable and there is the possibility of storing a mask. In this way of working, the color slide is read in transmission, without that through the arrangement of the duplicating material in the light path, light losses or color shifts enter, creating an altered optical density signal that corresponds to the fuzzy luminous mask representing the color template, which is used to control the contrast and the exposure level required for reproduction.

Another object of the present invention is, in one Color contact copier to create a mechanical device that allows to arrange the color image receiver quickly over the original color and then immovably in close contact with it while the image receptor exposes will.

In addition, there is another object of the present invention in it, a scanning light source with electronically controlled spectral and brightness compensation to create the specific needs of dynamic color control certain Emulsions can be adjusted over their usable exposure range.

According to the invention, this object is achieved in terms of Color contact copier characterized by (a) a single device for scanning of the image carrier with at least one point-shaped scanning light beam and for exposure of the image receiver, (b) at least one photodetector for measurement the radiant energy penetrating the image carrier and for generating on it optical density related signals, (c) one related to optical density Signal-responsive modulation device for the scanning light beam to change the effective contrast range and the exposure level of the signals, (d) a Luminous mask memory for storing the changed, related to the optical density Signals representing a density-corrected luminous mask of the image, (e) a Contact device with which the opaque image receiver after the Scanning and storage of the luminous mask brought into close contact with the image carrier is, and (f) an exposure device for exposing the image receiver with the scanning light beam through the image carrier, the density corrected Luminous mask of the scanning for the exposure is superimposed and due to the change the exposure effect of the scanning light beam produces a density-corrected image on the Image receiver is created.

Developments and advantageous embodiments of the invention Color copier are characterized in the other claims.

According to the invention, this object is achieved in terms of Method characterized by the following steps: (a) Arranging a color master above a point-shaped scanning light source with adjustment devices for changing the blue, green and red light components, (b) pre-scanning the color original with the scanning light point while measuring the light penetrating the color original Determination of the minimum and maximum optical density of the material, the difference the maximum and minimum optical density and the mean optical density, (c) Compare the difference with a predetermined target value to generate a Control signal for the scanning light point, the setpoint being the maximum permissible Corresponds to the contrast limits of the image receiver, (d) scanning the color original and Storing the scanning signal while changing the scanning light point at the same time by the control signal and storing the light intensity transmitted by the color original in a memory, the controlled change changing the contrast adjustment limits and determines the required exposure level and the changed light intensity represents a modified luminous mask of the color original to be duplicated, (e) arranging of the image receiver in close contact on the color original, and (f) Exposing the color original by means of the scanning light point while changing the same by the stored luminous mask signal to maintain the specified contrast limits of the image receptor with regard to the exposure level and the contrast adjustment limits at exposure.

Advantageous refinements of this method are set out in the subclaims marked.

The invention is particularly suitable for working with common Color copier film or paper such as Eastman Kodak Aerochrome Duplicating Film Type 2247; Eastman Kodak Aerial Negative Color Film Type SO 149, Kodak 2203 RC Copy Paper, Ciba-Geigy Cibachrom color copier paper and the like. These particular emulsions are in comparison photographically insensitive to conventional black-and-white copier materials and beyond essentially over most of the visible spectrum for the transmitted light impermeable.

When trying to make a film as true to the original as possible copy is usually used because of its higher speed and its superior Resolution prefers a contact copying process, albeit with a substantial increase in contrast can occur.

Conversely, in projection copying, the lens may cause a Loss of quality of the image, for reduced contrast and for loss of light, everything that can be avoided with contact copying.

Cathode ray tube scanning copiers often use this light transmitted through the raw film to control the exposure level and / or the contrast when duplicating; but this is with the above-mentioned color copying materials extremely difficult because they let so little visible light through.

The present invention is for use with opaque Color copy film and paper materials are particularly useful in a contact copier system; it enables an automatic control of the exposure level and an automatic one Change of the contrast range in adaptation to the permissible contrast range of the image receiver.

In contrast to the known transparent copier for Single lens reflex cameras (US Pat. No. 4,263,001) is the color copier according to the invention a contact copier with a compound light spot for scanning the original film and for exposure of the image receptor. When using the same photographic Copy material, the color copier according to the invention works even with high-speed optics in the known device at least one order of magnitude faster; when using the same copier emulsion, it is usually 40 times or more faster to taking into account that most copier lenses have apertures in the area of f = 2.5-3.5.

With regard to the previously known devices (US-PS 4,263,001, 4,415,709) it should be emphasized that the use of a single location for the scanning light point in itself already advantages for the accuracy of the alignment of the contrast controlling Has luminous mask to the template.

The device of US Pat. No. 4,145,709 is designed to operate below Use of black and white copy paper with variable contrast is provided, whereby the effective increase in contrast is changed through the use of color filters, to change the spectral content of the light source used for exposure. The device according to the present invention is for use in a color copier determines and changes the copy contrast through education and storing an electronic unsharp mask of the image and by overlaying it of the image with this mask in the form of a luminous mask during exposure.

The device according to US Pat. No. 4,145,709 dismantles the original Sampling in one place and exposing it in another place together again, while in the device according to the invention on a single Location read and scanned and the optical coupling between original and copy is maintained during exposure. The device of US Pat. No. 4,145 709 therefore requires a huge amount of storage space to keep all of them under high definition store scanned image information between reading and exposure stations and to transmit, while in the device according to the invention only the signals need to be saved that the blurred luminous mask for exposure represent.

According to the invention, a single scanning light source is used for the prescanning and exposure scanning, while according to US Pat. No. 3,961,366 for the Pre-scanning a vidicon and a separate scanning light point for exposure is used. It was found many years ago with a similar device that that significant alignment problems when projecting the second, contrast-modified Consist of the video image on the optical image.

Furthermore, such a projection can only one end of the contrast range on the copy and not both, as this only adds light can.

Finally, the device according to the invention is a contact copier, which by itself delivers a higher image fidelity than a projection copier.

An embodiment of the invention is shown in the figures and is explained and described in detail below with reference to the reference symbols. 1 shows a block diagram of the color contact copier according to the invention; Fig. 2 is an exploded perspective view of the contact device in the color contact copier according to Fig. 1, Fig. 3, 4 a plan view of the color contact copier according to FIG. 1 with the transport device in the scanning or copying position, FIG. 5 a diagrammatic sectional view of the contact device according to FIG. 2 in copying position and Fig. 6 is a block diagram of the signal processing in the color contact copier according to Fig. 1.

Typically, cathode ray tube copiers operate with electronic ones Contrast adjustment (i.e. "masking") with a single cathode ray tube as a Exposure light source. As mentioned earlier, such copiers require when using a cathode ray tube equipped with mixed phosphorus may be excessive a lot of time to get certain color image receivers such as film or paper through the necessary Correctly expose color correction filters. Corresponding to Fig. 1 is a triple arrangement provided by cathode ray tubes known as the triniscope and is similar to the arrangement used in projection color television. These Triple arrangement brings a variety of advantages. The absolute light intensity of a such Arrangement is many times larger than that of a three-beam cathode ray tube Cover mask, since with the latter a large part of the radiation power in the mask structure is lost and is no longer available for the after-fluorescent screen. Further is the luminescent screen of each cathode ray tube in the triple arrangement with one single continuous phosphor coating, which only the light of a basic color emits: red, blue, or green (or other combinations). In contrast, have the conventional three color cathode ray tube arrangements with separated points or chopsticks on the fluorescent screen. Finally, the triple arrangement enables compared to a cathode ray tube with a mixed phosphor, a dynamic one Color temperature control within the contrast limits of each cathode ray tube through which the adjustment of red, green and blue copier light for suitable photosensitive Raw material produced and over an equivalent neutral density range of 0.0 to 2.0, which is determined by the associated brightness control sensors, can be sustained without relying on color correcting filter assemblies in the light path having to fall back.

The triple arrangement shown in Figure 1 has four different ones possible ways of working. The first is the one for consideration in which all cathode ray tubes work at high intensity and with a fast raster scan so that the The slide to be reproduced can be viewed from above under transmitted light.

The second mode of operation is the prescan, during which the optical Density of the slide image is determined, with the intensity-modulated contrast adjustment only takes place to a certain extent. During this determination, a D-MIN signal becomes generated that the minimum optical density of the slide (or negative) represents, a D-MAX signal representing the maximum optical density of the slide, an n D signal that is the difference between the minimum and maximum optical Density on the slide is determined and an integrated D-SUM signal that the required Represents copy exposure. The third mode of operation is a memory scan, in which the color original is scanned by the light source; thereby the used in prescanning certain optical densities in order to obtain a changed, to generate optical density related signal suitable for use with the required blurred light mask. During this memory scan only intensity modulation is preferred, although simultaneous intensity and speed modulation would be possible. After the memory scan is complete the color image receiver is brought into close contact with the color original. In the fourth or exposure mode of operation, finally, will be used when scanning for the luminous mask generated changed signals related to the optical density to control the exposure and to create the blurred, contrast-reducing ones Luminous mask used during the exposure of the image receptor of the photographic Original artwork is overlaid.

Intensity and speed modulation are available, to increase the copying speed significantly. It should be noted that the Prescan, memory scan, and exposure scan do not affect the original is moved and the alignment between that through the cathode ray tube light source generated raster and the image details of the color original remains constant.

Fig. 1 shows a triple arrangement with three cathode ray tubes 11, 12 and 13 and associated projection lenses 14, 15 and 16. These lenses do not necessarily have image quality, as their main job is therein consists of collecting the greatest possible amount of light with the smallest possible reflection spot.

Each cathode ray tube 11,12,13 can also have a single sharp-edged Belt filters 17, 18 or 19 may be provided in order to minimize the amount of color added and to maximize the spectral purity of each phosphor. Additional Color filtering is not required as the spectrum of the light source is responsible for the exposure can be set to different types of color copying in the triple arrangement by the relative emissions of the individual cathode ray tubes 11, 12, 13 are changed, which are typically centered at about 450 nm, about 530 nm and about 620 nm. this corresponds to conventional blue, green and red copier light. Others can Phosphors selected or colors determined to get the most effective exposure speed and spectral balance for photosensitive other than those mentioned here Materials to achieve.

Red, green and blue color temperature detectors 20, 21 and 22 are on a color temperature controller 23 fed back, through which the reaction of cathode driver circuits 24 can be changed. The light mixture from the individual cathode ray tubes 11,12,13 of the triple arrangement is through an electronic negative feedback circuit on each cathode ray tube 11,12,13, thereby reducing the blue / green and red / green emissions can be tailored to selected conditions.

The sum of the intensity of all three emissions is then given by the Feedback remains constant despite changes in the blue / green or red / green ratio level held. In this way the color temperature of the light source is according to the spectrum adjustable without changing the intensity. Requires the optical density of the color original 25 upon exposure a change in the intensity of the light source, so can electronic matching circuits change the color mixture and the required Change in the color temperature of the light source over the density range scanned by the slide produce. The triple arrangement ultimately forms a light source that is electronic can be adjusted to "white". This light source (Fig. 1) scans an ordinary one Raster format between positions A and A '. As mentioned above, the Light source as a single point of light moving at a scanning speed above the visual inertia when looking at a continuous planar light source of white light approximates. Through the color temperature control 23, the spectral Adjustment of the scanning point from white light to the known spectral properties of the photographic image receiver 26 or the color original 25 or both will.

The color contact copier shown in Fig. 1 is located in the essential in exposure position; the color master 25 forms a continuous Strip and the photographic image receptor 26 a second continuous strip. The color original 25 and the image receiver 26 can before exposure by a movable support plate 27, vertically along the line indicated by arrows B and B ' Path up and down can be brought into direct contact. The image recipient 26 is normally located in a light-tight moving transport device 42, which will be described below. Above the carrier plate 27 and the color template 25 is a scatter filter 28, which the reflection components in the Light of the scanning light spot during the prescan and the memory scan scattered.

During viewing, prescan and memory scan is the Image receiver 26 arranged in the dark and outside the light path of the triple arrangement. During the prescanning, the photodetectors 29, 30 and 31 for red, green and blue light, an evaluation of the image to be copied is carried out. at the neutral scatter filter 28 in the light path is close to the evaluation, but not necessarily in direct contact with the color template 25. How from 1, the projected scanning light point falls on the in this way Dia and is then viewed through the diffusion filter 28 by the photodetectors 29-31. The scatter filter 28 is used to eliminate Callier effect problems by removing the reflective optical densities can be converted into corresponding scattering densities. The photodetectors 29-31 are placed at a sufficient distance from the copy platen to avoid difficulties due to the cos-dependence on the angle of incidence of light to be kept as low as possible. At a distance of approx. 107 cm (42 in), the relative recording error is included about 0.02 density units. The common output of the photodetectors 29,30,31 in the pre-scanning is via an amplifier 32 and a switch 33, which is between the pre / memory scanning and the exposure scanning switches to a contrast adjustment unit 34 with intensity and speed modulation in which the various Image densities are determined.

The contrast adjustment unit 34 becomes more precise in connection with FIG. 6 explained. Their main task, however, is to obtain the maximum optical density of the Signal D-MAX representing color original 25, a the minimum optical density of the Color original 25 representing signal D-MIN and a general one To generate the degree of exposure of the color original 25 representing the difference signal a D. The optical densities are evaluated and combined to give two exposure values gain, namely the exposure level and the contrast adjustment.

After the prescan, a program control 36 causes a triggered memory scan that the switch 33 the output of the photodetectors 29-31 to a memory 35 for the blurred luminous mask, which has the shape of a Image storage tube (Princeton Electronic Products Inc., North Brunswick, New Jersey 08902; Princeton PEP-500 Lithocon Solid State Image Storage) or the like.

The scatter filter 28 is still in place during the memory scan in the optical path, and the outputs of the photodetectors 29-31 become simultaneously given to the luminous mask memory 35 and the contrast adjustment unit 34. There the contrast adjustment unit 34 control signals for both the cathodes of the cathode ray tubes 11,12,13 as well as for the deflection 74 generated on the above-mentioned exposure values the light source of the triple arrangement dynamically changes its intensity and color matching with respect to the designated and desired properties. The raster scan also determines address locations that are concurrently in the luminous masks memory 35 can be identified. This way there will be differences in the visual Density in the contrast-adjusted image was detected by the photodetectors 29-31 and in the light mask memory 35 as changed, related to the optical density Signals saved.

After the memory scan, the electronic system stops to enable the image receiver 26 to be connected to a light-tight transport device 42 is arranged directly above the color template 25. The movable support plate 27 then ensures close contact between the color original 25 and the image receiver 26. This movement of the photographic material is controlled by the program control 36 via the Transport control 37 caused. After close emulsion contact ensured is, the program controller 36 switches to the exposure cycle, the signals of the Photodetectors 29-31 are blocked by switch 33, and those in the light mask memory 35 stored, changed, optical density related signals in the subsequent exposure cycle to control the contrast adjustment unit 34 used. When the exposure is finished, the cathode ray tubes 11,12,13 blanked, the up and down movable support plate 27 from its position above the level of the color original 25 lowered, the image receiver 26 in the light density Transport device 42 withdrawn and, if the device after the search and copy process works, the copying process ends. However, if the color contact copier is used for repeat copying set, the carrier plate 27 lowers after each exposure, a suitable one Quantity of image receptor 26 is conveyed further by transport motors 38, the carrier plate 27 raised again to establish contact between the materials, and a new exposure cycle begins without re-prescan or memory scan. The operation of the selection and display circuit 39 will be discussed further below described in more detail with FIG. 6.

According to Fig. 2, the color template 25 normally consists of long, continuous strips of originals Transport reels 40, 41. Usually the color templates 25 are between the steps of the search and Copying process moved one after the other. Through the selection and display circuit 39 however, the copier can move the color originals 25 frame by frame if necessary and make one or more copies of each.

The image receiver 26 is located in a light-tight transport device 42 with a feed cassette 43 for the raw material and a receiving cassette 44. A dark slide 45 closes the lower part of the transport device 42 to prevent light from falling onto the image receptor 26 from the outside. As already mentioned, The material can be used for negative or positive color copy film or color copy paper Be copying positives or negatives. The transport device 42 is for propulsion in two directions, the horizontal with C-C 'and the vertical is designated by D-D ', specially set up. After the memory scan has expired the transport device 42 is moved laterally in the direction C-C 'until it is located directly above the selected color template 25. At this point it will the dark slide 45 is withdrawn from the transport device 42 and the entire transport device 42 lowered in the direction D-D '(see. Fig. 2). While the transport device 42 moves downward, the transparent support plate 27 moves in the direction B-B 'up. The relationship between these movements is related below further described with FIG. 5.

The lateral movement path of the transport device 42 is off 3 and 4 show the color contact copier in the view / prescan mode (Fig. 3) or in the exposure mode (Fig. 4). Fig. 3 shows a lightproof Outer housing 46, which is equipped with movable doors 49 which are opened above the carrier plate 27 for viewing the color original 25. As mentioned earlier, the CRT light source operates while viewing with high scanning speed and high intensity to continuously produce white light for viewing. In the outer housing 46 are the electronic Circuits, and the photodetectors 29-31 are in the upper part of the outer housing 46 arranged.

The transport bobbins 40,41 can by hand cranks 48 or by hand operated remotely by torque drives (not shown). In the The illustration of FIG. 4 is the light-tight transport device 42 over the light-permeable Carrier plate 27 has been brought, and the doors 49 of the outer housing 46 are closed.

The color contact copier is then in a position in which single exposures or multiple exposures can be triggered in incremental repetition.

Nevertheless, there is a way of working with individually cut templates and recipients are not excluded.

Fig. 5 shows the relationship between the carrier plate 27, the color original 25 and the image receiver 26.

When contact copying is essential that the color original 25 and the Image receptor 26 in close emulsion contact over the entire surface to be copied stay.

This is achieved in that the image receiver 26 in the D-D ' designated direction is lowered, with two parallel transport rollers 50,51 by its lower tangent to the image receptor 26, a dashed line Define T-T 'designated plane.

To the extent that the image receiver 26 is between the transport rollers 50,51 is stretched and lowered to the color master 25, the permeable moves Carrier plate 27 in the direction B-B 'upwards and brings in order to the color original 26 and the image receptor 26 in close contact. The edges 27a, 27b of the carrier plate 27 are in a direction transverse to the direction of material transport Direction beveled to avoid any local stress or damage to the paint materials to exclude. The relative movement between the carrier plate 27 and the transport rollers 50, 51 is greatly exaggerated in FIG. 5 for the sake of clarity. Important is However, that the clamping surface of the transparent support plate 27 on the of the horizontal transport rollers 50,51 certain, horizontal plane T-T 'rises and that as soon as a desired image of the color original 25 is selected for reproduction and is correctly aligned over the carrier plate 27, despite the subsequent layout and moving away the carrier plate 27 no further change in the position of the color original 25 more may take place.

The mode of operation of the contrast adjustment unit 34 is described in connection described with FIG. 6. Therein represent the output signals of the photodetectors 29-31 the optical densities of the color original 25 at each instant of the raster scan This signal is amplified at 32 and passed through switch 33 to a data collector 60 and from its output to a detector 61 for the maximum optical density of the color original 25 and a detector 62 for the minimum optical density of the Color template 25 given. The D-MIN and D-MAX signals from detectors 61,62 become in a detector 63 for the difference signal d D to determine the maximum density range of the color original 25 is summed up. In this way, the system evaluates during the prescan the color template 25 for determining a D-MIN signal, which is the minimum optical Density of the color original 25 represents a D-Max signal, which is the maximum optical density of the color original 25, and a dD signal that represents the difference between D-MIN and D-MAX.

After determining a D by the prescan, it becomes the nD signal in a comparison circuit 64 compared with a target value that is the permissible Contrast range of the image receiver 26 in the color contact copier corresponds. The comparison circuit 64 generates an intensity / speed modulated Contrast correction that is just sufficient to match the AD area of the color original 25 the image receiver 26 to reproduce correctly. The one from the comparison circuit 64 selected contrast adjustment area is indicated by one of a group of in a modulation circuit 66 arranged diode pair selected diode pair determined (cf.

the diode pairs in the modulation circuit according to FIG. 6 of the DE-OS 30 10 945); in the contrast adjustment unit 34 there are seven different contrast areas intended. The comparison circuit 64 automatically selects the pair of diodes the least amount of contrast adjustment for the exposure of the color original 25 within the permissible contrast limits of the image receiver 26 requires how it is determined by the setpoint that is set at the contrast setting 65 will. The contrast adjustment unit 34 is also associated with the selection and display circuitry 39 equipped, which has a plurality of display devices that display the densitometric Data indicate D-MIN, D-MAX, and the contrast adjustment range obtained by the prescan as best suited for the reproduction of the color original 25 just examined have been found. If necessary, the recommended range of contrast adjustment compared with the densitometric data and the actual amount of to be used Contrast adjustment can be set independently. In this case this area becomes entered via a selector switch 67 for contrast adjustment.

The prescan also automatically determines two different signals for the exposure level. The first, the sum signal D-SUM = n (D1 + D2 ... Dn) becomes from the optical density integrator 68, the area integrator (counter) 69 and the dividing circuit 70 are formed. This is a sum average of all of them values of the optical density detected in the prescan, which are used to determine the correct exposure level for each color original evaluated by the prescan 25 can be used. A combination signal D-COMB = (1-k) D-SUM + (1-k) K D-MIN + K (k) D-MAX is determined by a combination circuit 71 for the optical density, where K and k are variable resistances. It enables the exposure level to be aligned according to your choice according to D-SUM, D-MIN, D-MAX or an average value of the optical density. Aerial photographs should better be aligned with D-SUM, especially if they are tessellated Composition, but picture photographs better according to D-MIN or D-MAX depending on whether it is a "high-key" or a "low key" image. Through the dialing and Display circuit 39 creates a display that makes it possible to choose between the System automatically determined exposure level and one manually on a selector circuit 72 set exposure level to choose. The one from the combination circuit 71 automatically determined or set manually at the selector circuit 72 exposure is then compared with the data for the contrast adjustment range from the comparison circuit 64 and from the modulation circuit 66 or the selector switch 67 combined, wherein Via the data collector 60 and a current transformer 73, a value lying in the middle for the exposure level is obtained.

If the contrast gradation and the exposure level are selected by hand, a blocking circuit 75 is actuated to prevent prescan, and the movement 76 blocked.

After the pre-scan is complete, a memory scan can be initiated that an intensity and speed modulation of the cathode ray tubes 11-13 combined. Through the data collector 60, the output current of the photodetectors 29-31 changed so that it is within the determined by the modulation circuit 66 Exposure requirements remains, and so reproduced by the current converter 73 that the intensity of the triple arrangement by the cathode driver circuit 24 and whose deflection speed can be changed automatically by the deflection control 74. The intensity and the speed (or downtime) are changed, but only the intensity or only the speed or only the Downtime can be changed.

As already mentioned, only the intensity modulation is used during the scanning used, while for the exposure the intensity and the speed resp.

the intensity and the downtime can be changed together.

The selection and display circuit 39 shows the exposure level, the Exposure value and the contrast gradation as determined during the prescan or have been set arbitrarily on the selection circuits 67, 72.

The exposure level is determined by the one in the middle of the range optical density of the color original 25 to be reproduced is determined. As in the context mentioned with the combination circuit 71, a variety of information including D-MAX, D-MIN and D-SUM or their combination can be used. With a preferred one Embodiment is the exposure strength (E.L.) by a density comparison after: E.L. = (1/4) D-MAX + (1/4) D-MIN + (1/2) D-SUM determined. Of the Exposure value represents the amount of exposure needed to match the photographic Sensitivity of the image receiver 26 is required and can be controlled via a two-decade wheel switch can be entered at the selection circuit 72. The contrast gradation is a measure of the actual mask area applied as a function of the required Light mask area; it is based on the density range measured on the color original 25 and the known (calibrated) contrast characteristics of the image receiver 26. Die Contrast gradation can either be entered manually or derived from the prescan will.

As already mentioned, you can use the contrast setting when entering 65 can be compared with the contrast properties of the image receiver 26.

During the exposure, the color contact copier controls the copy contrast in two ways: (a) by changing the intensity of the light from the scanning light source emitted radiation; (b) by changing the speed of the light source outgoing scanning beams. For this purpose, the image contrast is divided into coarse "and" fine ", i.e. according to density differences over large or small areas. Previously, electronically In contrast-adapted copies, the contrast in detail at the expense of the overall contrast enlarged. In other words, compared to the size of the scanning light spot large areas exposed only so far that in the copy there is one in the middle optical density was achieved that is in the linear part of the D-Log E curve of the image receptor 26 lies. This increases the fine contrast because it is the linear part of the curve has a contrast gradient that is larger than that in the Beginning and ending parts. However, the contrast adjustment unit 34 uses one kind the contrast control, in which the contrast adjustment for a to be selected, in the middle tone begins and from there to higher and lower optical densities advances.

One input to the contrast adjustment selection circuit 67 Value 0 results in no contrast adjustment.

All other contrast control settings result in specific ones Contrast adjustments. If you enter the value 1, a density compression between 0.12 detected density units above and below that set on the center Get exposure level. With the contrast adjustment 1 (and an assumed Exposure strength (E.L.) of 1.2 density units) is therefore in the range of 0 No contrast adjustment up to 1.08 density units, from 1.08 to 1.32 density units full contrast adjustment and from 1.32 to any higher optical density value no contrast adjustment either. Correspondingly, there is a contrast adjustment 2 a compression in a range of -0.25 density units, i.e. below the same Conditions will be from 0 to 0.95 density units no contrast adjustment, from 0.95 up to 1.45 density units full contrast adjustment and from 1.45 to all higher Optical density values do not obtain a contrast adjustment. When adjusting the contrast 3 the compression takes place in the range + 0.38, with 4 in the range + of - 0.5, with 5 in the range of + - 0.6, at 6 in the range of - 0.88 density units and at the end at 7 over the entire density range scanned. Explanation: If the scanned, density range determined by the color original 25 by the detector 63 for the difference signal 1.8, the gamma of the reproduction material 1.5 and the required density range the copy too 1.8, the required compression is: (1.5.1.8) - 1.8 = 2.7 - 1.8 = 0.9 = +0.45; therefore there is an adjustment of the contrast adjustment to the value 4 required to keep the optical densities of the reproduction within to maintain the permissible contrast limits of the image receiver 26.

The color contract copier described above achieves one automatic control of the exposure level and the slope of the selected and contrast imparted to the image receiver 26 and at the same time with respect to known ones Devices a substantial increase in copy speed. In addition, enables the mask storage working with reproduction materials necessary for the exposure radiation are essentially impermeable.

It should also be noted that if the polarity is reversed, the Luminous mask memory 35 input signals of the density range of color originals 25 can be enlarged with low contrast during the main exposure. Instead of of the cathode ray tubes, other scanning light sources such as lasers can also be used will.

Claims (25)

Claims 1. Color contact copier for exposing an image receiver by means of a point-shaped scanning light beam proceeding from an image carrier, wherein the image receiver for at least one spectral component of the scanning light beam is essentially impermeable according to patent ... (patent application P 32 04 581.6), characterized by (a) a single device for scanning the image carrier (25) with at least one point-shaped scanning light beam and for exposing the Image receiver (26), (b) at least one photodetector (29,30,31) for measuring the the image carrier (25) penetrating radiation energy and for generating on it optical density related signals, (c) one related to optical density Signal-responsive modulation device (34) for the scanning light beam for modification the effective contrast range and the exposure level of the signals, (d) a light mask memory (35) for storing the changed on the optical Density related signals representing a density corrected luminous mask of the image; (e) a contact device with which the opaque image receiver (26) after the scanning and storage of the luminous mask in close contact. with the image carrier (25) is brought, and (f) an exposure device for exposure the image receiver (26) with the scanning light beam through the image carrier (25), wherein the density corrected luminous mask is superimposed on the scan for exposure is and by changing the exposure effect of the scanning light beam a density corrected Image is created on the image receiver (26). 2. Color copier according to claim 1, characterized by (g) a Current transformer (73), which related to the changed, related to the optical density, the Luminous mask of the image representing the signal responds and in a predictable manner related first and second output currents generated, (h) one on the first output current responsive modulator to change the intensity of the Scanning light beam corresponding to the changes in the first output current, and (i) a deflection control (74) responsive to the second output current for changing according to the scanning speed or standstill time of the scanning light beam the changes in the second output current, with the intensity and the speed or the idle time of the scanning light beam according to the changes in the changed, related to the optical density and representing the luminous mask of the image Signal is changeable. 3. Color copier according to claim 1 or 2, characterized in that that the hIodulationseinrichtuna (34) (a) a prescan circuit for forming a the signal (D-MIN) corresponding to the minimum optical density of the image carrier (25), a signal corresponding to the maximum optical density of the image carrier (25) (D-bEX), a difference signal (S D) formed therefrom and one of the sum of all corresponding sum signals determined during the pre-scanning optical densities (D-SUM), and (b) a comparison circuit (64) for comparing the difference signal (d D) with a setpoint value representing the contrast range of the image receiver (26) and for generating a signal for the contrast adjustment range and (c) a the sum signal (D-SUM) and the contrast range signal responsive control circuit (66) to set the exposure level and the contrast adjustment range for the scanning light beam during the scanning and storage of the luminous mask of the Image carrier (25). 4. Color copier according to one of the preceding claims, characterized characterized in that the memory (35) for the luminous mask has a storage tube a plurality of microcapacitor storage elements or the like. Is. 5. Color copier according to one of the preceding claims, characterized characterized in that the memory (35) for the luminous mask has an A / D converter and has a digital memory. 6. Color copier according to one of claims 1 to 5, characterized in that that the contact device (a) contains a transport device (42) by means of which the image receiver (26) from a first position adjacent to the image carrier (25) can be moved into a second position directly above the image carrier (25), as well as (b) a transparent carrier plate (27) which is below the image carrier (25) is attached and in a first position out of contact with the image carrier (25) and in a second position this is in close contact with the image receiver (26) is pressed. 7. Color contact copier for exposure of opaque photographic material by scanning a photographic image with a A plurality of cathode ray tubes characterized by (a) a Light source with three cathode ray tubes (11,12,13), the first one red, the one the second has a green and the third has a blue emitting luminescent screen, and with projection lenses (14,15,16) for each cathode ray tube (11,12,13), by means of of which the light beams emanating therefrom can be focused to form a single scanning light point are, (b) at least one photodetector (29,30,31) for measuring part of the light emanating from the scanning light point after change by the photographic Image (25) and for generating signals related to its optical density stand, (c) a first scanning and storage device for scanning the photographic Image (25) with a responsive to the optical density related signals first control device for changing the effective contrast range and the Exposure strength of the scanning light point and with a memory (35) for storing the altered optical density related to the memory scan obtained Signals which represent a density-corrected luminous mask of the image (25), (d) a contact device with which the opaque photographic material (26) after the memory scan has elapsed, in close contact with the photographic one Image (25) is brought, and (e) an exposure scanner to expose the photographic material (26) by means of the scanning light point with an altered optical density related signal in the memory (35) responsive second control device for superimposing the memory scanning obtained luminous mask and the exposure scan to form a corrected Exposure strength and a corrected contrast adjustment range for the exposure the photographic material (26). 8. color copier according to claim 7, characterized in that one Color temperature control (23) to change the proportions of the red, green and blue Emission of the cathode ray tubes (11,12,13) for the purpose of adapting the combined light emission the spectral sensitivity of the emulsion of the respective photographic material (26) is provided. 9. color copier according to claim 7 or 8, characterized in that that a prescanning means for scanning a predetermined portion of the photographic Image (25) is provided before the memory scan, which is based on the contrast area of the photographic material (26) representing setpoint and for the signal obtained in the memory scan, modified according to the optical density automatically sets the exposure level and contrast adjustment range. 10. Color copier according to one of claims 7 to 9, characterized in that that the exposure scanning device comprises (a) a current converter (73), which on the changed, related to the optical density, representing the luminous mask of the image Signal responds and predictably related first and second Output currents generated. (b) a modulator responsive to the first output current for Change the intensity of the combined scanning light spots from the three cathode ray tubes (11,12,13) according to the changes in the first output current, (c) one on the second output stream responsive modulator for changing the scanning speed or downtime of the combined scanning light points according to the changes in the second output current, with the intensity and the speed or the Standstill time of the scanning light point according to the changes in the changed, signal related to the optical density and representing the luminous mask of the image is changeable. 11. Color copier according to one of claims 7 to 10, characterized in that that the sampling memory (35) is a storage tube with a plurality of microcapacitor storage elements or the like. 12. Color copier according to one of claims 7 to 11, characterized in that that the sampling memory (35) has an A / D converter and a digital memory. 13. Color copier according to one of claims 7 to 12, characterized in that that the contact device (a) contains a light-tight transport device (42), by means of which the photographic material (26) is extracted from one of the photographic image (25) adjacent first position to a second position immediately above the photographic image (25) is movable, and (b) a transparent support plate (27), which is attached below the photographic image (25) and in a first position out of contact with the photographic image (25) and in a second position this pressed in close contact with the photographic material (26) is. 14. Color copier according to claim 13, characterized in that the transport device (42) has first and second transport rollers (50, 51), those in the second position of the transport device (42) parallel and opposite one another with respect to the path of the photographic image (25) are arranged, and that the Support plate (27) curved and back and forth between the first and second positions is movable and in the second position in the manner between the transport rollers (50,51) is arranged that the curvature of the support plate (27) above the by the axes of the transport rollers (50,51) certain plane is located. 15. Color contact copier for exposing an opaque photographic material by scanning a color original by means of a point-shaped Light source, characterized by (a) an exposure device with cathode ray tubes (11,12,13) for scanning the color original (25) with a Scanning light point and with separate adjustment devices for the relative intensity the three primary colors produced by it; (b) at least one photodetector (29,30,31) for measuring the light penetrating the color original (25) and for generating signals related to its optical density, (c) one to the optical Density related signals responsive pre-scanning circuit for the scanning light point to change the effective contrast range and the exposure level of the signals and for generating by prescanning one of the minimum optical density of the Color original (25) corresponding signal (D-MIN), one of the maximum optical density the signal (D-MAX) corresponding to the color original (25), a difference signal formed therefrom (d D) and a summation signal (D-SUM) for the exposure level, (d) a comparison circuit (64) to compare the difference signal (aD) with one of the contrast range of the photographic Material (26) representing setpoint and for generating a signal for the contrast adjustment range, (e) a memory scanning device for scanning the color original (25) by means of the Scanning light point and for storing a changed, optical density related signal in a Image storage tube (35), the scanning light point being scanned by the difference signal (t D) and the summation signal (D-SUM) for generating a density-corrected luminous mask the color template (25) is changeable, (f) a contact device with which the opaque photographic material (26) in close contact after the memory scan is complete is brought with the color original (25), (g) an exposure scanner to Exposing the opaque photographic material (26) to the scanning light point after passing through the color template (25). which exposure scanner on the stored, modified, optical density related signal is responsive and an exposure scan with a superimposed density corrected luminous mask for the purpose of changing the exposure effect of the scanning light point and so a density-corrected image is generated in the opaque material (26). 16. Color copier according to claim 15, characterized in that a modulation device (66) for modulating the intensity and the speed of the scanning light point is provided during exposure scanning 17. Color copier according to claim 15, characterized in that a modulation device (66) for Modulation of the intensity and the downtime of the scanning light point during the exposure scan is provided. 18. Color copier according to one of claims 15 to 17, characterized in that that the memory scanning device comprises an image storage tube (35) having a plurality of microcapacitors for storing the changed, on the optical density related signal. 19. Color copier according to one of claims 15 to 18, characterized in that that the contact device (a) contains a transport device (42) by means of which the image receiver (26) from a first position adjacent to the image carrier (25) can be moved into a second position directly above the image carrier (25), as well as (b) a transparent carrier plate (27) which is below the image carrier (25) is attached and in a first position out of contact with the image carrier (25) and in a second position this is in close contact with the image receiver (26) is pressed. 20. Procedure for automatically changing the exposure level and the contrast adjustment limits in a color contact copier with an opaque one photographic image receiver according to patent ... (patent application 32 04 581.6), characterized by the following steps: (a) Arranging a color original above a point-shaped one Scanning light source with adjustment devices to change the blue, green and red light components, (b) Pre-scanning of the color original with the Scanning light point with measurement of the light penetrating the color original for determination the minimum and maximum optical density of the material, the difference between the maximum and minimum optical density and mean optical density, (c) Compare the difference with a predetermined target value to generate a Control signal for the scanning light point, the setpoint being the maximum permissible Corresponds to the contrast limits of the image receiver, (d) scanning the color original and Storing the scanning signal while changing the scanning light point at the same time by the control signal and storing the light intensity transmitted by the color original in a memory, the controlled change changing the contrast adjustment limits and determines the required exposure level and the changed light intensity represents a modified luminous mask of the color original to be duplicated, (e) arranging the image receptor in close contact on the color original, and (f) exposing the color original by means of the scanning light point while changing the same through the stored Luminous mask signal to maintain the specified contrast limits of the image receiver regarding the exposure level and the contrast adjustment limits in the exposure. 21. The method according to claim 20, characterized in that during exposure (a) the stored signal is represented by a first and a second output stream (b) the intensity of the scanning light spot corresponding to the first output current is changed and (c) the speed of the scanning light point accordingly the second output current is changed. 22. The method according to claim 20 or 21, characterized in that to bring the image receiver into the various positions (a) this in a movable transport device is arranged and by means of this by a Waiting position can be moved into an exposure position and the image receiver by means of a pair of tensioning pulleys is clamped onto the color master and (b) the color master through a movable, translucent carrier plate in close contact with the image receiver is brought, and the carrier plate between a first position below the Tension rollers and a second position for exposure above one by the tension rollers specific tangential plane is reciprocable. 23. The method according to any one of claims 20 to 22, characterized in that that when scanning the color original and storing the scanning signal a plurality of microcapacitors in an image storage tube with a multitude of charges being charged. 24. The method according to any one of claims 20 to 23, characterized in that that when scanning the color original and storing the scanning signal that of the color original transmitted light is converted into a digital electrical signal and this Signal is stored in a digital memory. 25. The method according to any one of claims 20 to 24, characterized in that that emitting red, green and blue light to generate the scanning light point Cathode ray tubes are placed under the color template and the emitting Light on the color original is focussed out of focus in a single point of light.