US3241437A - Lamp house for photographic enlarging and printing devices - Google Patents

Lamp house for photographic enlarging and printing devices Download PDF

Info

Publication number
US3241437A
US3241437A US286595A US28659563A US3241437A US 3241437 A US3241437 A US 3241437A US 286595 A US286595 A US 286595A US 28659563 A US28659563 A US 28659563A US 3241437 A US3241437 A US 3241437A
Authority
US
United States
Prior art keywords
reflector
light
lamp
lamp house
printing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US286595A
Other languages
English (en)
Inventor
Thiels Albert Frans
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gevaert Photo Producten NV
Original Assignee
Gevaert Photo Producten NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gevaert Photo Producten NV filed Critical Gevaert Photo Producten NV
Application granted granted Critical
Publication of US3241437A publication Critical patent/US3241437A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
    • G03B27/52—Details
    • G03B27/54—Lamp housings; Illuminating means
    • G03B27/545—Lamp housings; Illuminating means for enlargers

Definitions

  • the present invention relates to a lamp house in enlarging and printing devices for the manufacture of photographic prints.
  • Lamp houses in photographic printing devices comprising a projection lamp, a hollow mirror behind the projection lamp, a condenser and a heat absorbing filter in front of the projection lamp.
  • the required uniform light intensity is realized by positioning one or more light diffusing plates, having a relatively high density, between the light source and the negative holder.
  • the projection lamp is placed at a rather great distance from the plane of the negative holder in order to attain a uniform light distribution.
  • great dimensions of the lamp house are necessary. All these factors diminish the photometric efliciency of the lamp house.
  • iodine lamps comprise a tungsten filament in a cylindrical quartz tube. During the manufacturing iodine vapor is introduced into the tube. This lamp is 25% more efficient than the common incandescent lamps for an equal lamp life. At equal power this lamp has a much more compact form than the common incandescent lamps; moreover, the light intensity and its spectral characteristics remain practically constant in aging.
  • One object of the present invention is to provide a lamp house for photographic printers capable of producing a light output equivalent to or higher than that of condenser-type systems and in which the temperatures of the negative or transparency are maintained at safe levels.
  • Another object of the invention is to provide a lamp house which produces a light output with a very uniform light distribution and the spectral characteristics of which do not alter in aging.
  • Still another object of the invention is to provide a lamp house which is very simple in construction and which does not necessitate an expensive tooling equipment.
  • the lamp house according to the present invention comprises a reflector which is shaped in such a way that in the printing plane the sum of the directly radiated and the reflected light gives a uniform light intensity, a tube shaped iodine lamp inside this reflector, and a frame before the aperture of the reflector comprising at least one heat absorbing plate and one light ditfusing plate; as well as openings for the inlet and outlet of a cooling air current passing on either side over the heat absorbing plate.
  • the reflector is therefore constructed of flat reflecting metal strips which are folded to a discontinuous profile.
  • these metal strips are either pebbled, or etched in a semi-mat way, at the interior side of the reflector (by pebbled metal strips is meant that these strips have a ribbed or otherwise profiled uneven surface, in two directions perpendicular to each other).
  • FIG. 1 is a schematic representation of a printing device.
  • FIG. 2 is the light distribution obtained in the printing plane by means of a parabolic reflector.
  • FIG. 3 is the light distribution in the printing plane by means of a reflector in the lamp house according to the present invention (Without any diffusing plate).
  • FIG. 4 is a diagram of the sum of the directly radiated and the reflected light.
  • FIG. 5 is a longitudinal section of the lamp house according to the present invention on line 55 of FIG. 6.
  • FIG. 6 is a cross section of the lamp house on line 66 of FIG. 5.
  • FIG. 7 is a perspective view of another embodiment of the lamp house according to the present invention.
  • FIG. 1 a printing device is illustrated schematically. It consists of the lamp house 11, the reflector 12, the iodine lamp 13, the frame 14 placed before the reflector aperture, the light diffusing plates 15 and 16 and a heat absorbing plate 17 in said frame, the negative 18 to be printed, the lens 19 and the printing plane 20 where the print material is positioned.
  • the interior side of the reflector can even be constructed with a mirror-like surface.
  • this theoretically ideal shape is different from the parabolic shape of a reflector which is quite well known in projectors and the like.
  • the parabola shaped reflector has the property of radiating all the light rays of the light source as a parallel light beam.
  • a cross section of such a light beam is considered, it is seen that the light distribution is not uniform, and if such a parabolic reflector is used in the lamp house 11, then a light distribution in the printing plane 20 is obtained as represented by the plane 21 of FIG. 2.
  • the light spot 22 represents an increased light intensity with respect to the other points of the plane 21, which phenomenon is a consequence of the direct radiation of the light source.
  • a similar light distribution is obtained by using an elliptical reflector when the lamp and the lens are situated in the two focal points.
  • a representation of such a light distribution, no negative being positioned in the device, is practically realized by exposing in the printing plane 20 a sheet of photographic paper to the light of the lamp house (without any diffusing screen) and by afterwards developing said photographic paper in a contrasty way.
  • FIGURES 5 and 6 A particularly interesting embodiment showing a discontinuous profile is represented in detail in FIGURES 5 and 6.
  • the reflector consists of the aluminum strips 26, 27 and 28.
  • the rectangular aluminum strip 26, positioned on the longitudinal axis of the reflector, is folded on a broken V-line and has 5 reflecting planes; each of the wedge strips 27 and 28 positioned on the transverse axis of the reflector has four reflecting planes.
  • the aluminum strips 27 and 28 are attached to the strip 26 by inserting their narrow ending extremities into the slots of the horizontal part of strip 26.
  • the reflector is fixed to the frame by means of the upper horizontal rims which are provided on the aluminum strips, and which are gripped between the frames 14 and 29.
  • the frame 29 is provided with two tubes 39 and 31 of insulating material in the center of which respective contact elements 32 and 33 are fitted for contacting the electrodes of the iodine lamp 13.
  • the reflector part 26 is provided with two openings 34 and 35 through which the iodine lamp is positioned into the reflector.
  • the interior wall 39 of the frame 14 has a mirror-like surface to limit the loss of light at the edges of the aperture.
  • the result of the light distribution of the reflector is represented in FIG. 3. It can be seen that the central light spot is now surrounded by a great number of other light spots. This representation is practically realized in the manner already described for FIG. 2.
  • the surrounding light spots result from the reflection of the light by the various reflecting planes of the reflector.
  • the reflection in the longitudinal direction of the frame is realized by the two left hand and the two right hand planes of the part 26 of the reflector (FIG. 6).
  • the reflection in the transverse direction occurs due to the four planes of each of the reflector parts 27 and 28 (FIG. 5).
  • the distribution of these light spots is not uniform (closer to each other the more the edges are approached to). It is determined in such a 'way that the sum 42, represented in dash and dot lines (FIG. 4), of the light directly radiated by the light source 13, represented by the curve 40, and of the light reflected by the reflector 12, represented by the curve 41, is constant over the printing plane.
  • the abscissa indicates the integration of the light intensity in the printing plane from one edge to the opposite edge.
  • the ordinate indicates the'magnitude of the light-intensity.
  • the number of reflecting planes is not limitative; instead of 35 luminous points (5 X7), a different number of luminous points can be chosen. However, the condition expressed by FIG. 4 should always be substantially complied with.
  • the exterior side of the reflector and of the protruding parts of the reflector part 26 are covered with a mat black paint, in order to assure a good heat radiation.
  • the heat absorbing plate 17 After being cut to size, the heat absorbing plate 17 is annealed to prevent bursting caused by the very high heating of the lamp 13.
  • the cooling air which is forced by a blower to circulate through the manifold 23 as indicated by the arrow, moves in the space defined by the light diffusing plates and 16, and carries off. the heat absorbed by the filter 17, leaving the said space through the openings 24, 25.
  • An iodine lamp of 625 w. 118 v. was used in the present examples. To increase the lamp life, the lamp was operated at under-voltage. An electric power of 350 watts was absorbed when the lamp was connected to an 80 volt supply.
  • the efiiciency differs according to the spectral regions and amounts respectively to 11 in the red region, to 13 in the green region and to 15 in the blue region of the spectrum.
  • the efficiency in the blue region of the spectrum is higher (also owing to the spectral reflection properties of the aluminum reflector) and is therefore a further advantage, more especially in printing masked negatives which show a pronounced blue light absorption.
  • the light diffusing plate 16 is located only at a distance of a few millimeters from the plane of the negative 18, whereby the dispersion of the light passing through the negative increases so that scratches and like injuries on the negative material, are reproduced in the least sharp way possible on the positive print.
  • a mask is placed before the surface 18, having an effective aperture of e.g. 24 x 36 mm.
  • an increase of light of about 20% is obtained.
  • the described example relates to the printing of negatives on positive paper, the production of negatives and of duplicate positives from positives, etc.
  • the lamp house according to the present invention is particularly suited for the additive printing method, wherein the partial exposures take place one after another, since this lamp house allows a considerable shortening of the relatively long printing times according to this method.
  • FIG. 7 A second embodiment of the lamp house reflector, in which the iodine lamp is now positioned in the longitudinal direction of the reflector, is represented in FIG. 7.
  • the reflector consists of a part 36, showing a continuously curved profile, and 2 flat sidewalls 37 and 38.
  • the filament length of the iodine lamp is equal to the length of the longitudinal side of the reflector aperture. Consequently, the light distribution is already constant in longitudinal direction so that only a uniform light distribution in the transverse direction must be assured.
  • the latter light distribution is attained by the part 36 of the reflector having a continuously curved profile in the transverse direction. Due to this part 36 more light is reflected closer to the edges than in the center. Said part is etched in a semi-mat way whereas the interior surfaces of the flat side walls 37 and 38 are mirrorlike.
  • the filter 17 is a heat absorbing plate. It is quite clear that in a modified construction of the lamp house, this plate in the known way can also be a heat reflecting plate. It is also possible to use both types of plate in one and the same lamp house.
  • a lamp house for use in printing or enlarging devices for manufacturing photographic prints comprising a reflector which consists of a first rectangular aluminum strip which folded on a broken V-line and which is provided with two outer rims, the reflecting planes of said first strip running parallel to the longitudinal axis of the reflector, a second and a third wedge-shaped aluminum strip which are also folded on a broken line and each are provided with one outer rim, and which are inserted in the first folded strip, the reflecting planes of said second and said third strips running parallel to the transverse axis of the reflector, a tube-shaped iodine lamp, the axis of which runs parallel to the transverse axis of the reflector, which is positioned within the reflector with its electrode ends projecting through two opposite holes which are provided in the said first folded aluminum strip, a first rectangular frame before the reflector aperture and resting on the rims of the folded aluminum strips and a second rectangular frame resting on the opposite sides of said rims and which is fixed to said first frame so as to

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)
US286595A 1962-06-28 1963-06-10 Lamp house for photographic enlarging and printing devices Expired - Lifetime US3241437A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL280310 1962-06-28

Publications (1)

Publication Number Publication Date
US3241437A true US3241437A (en) 1966-03-22

Family

ID=19753933

Family Applications (1)

Application Number Title Priority Date Filing Date
US286595A Expired - Lifetime US3241437A (en) 1962-06-28 1963-06-10 Lamp house for photographic enlarging and printing devices

Country Status (3)

Country Link
US (1) US3241437A (enrdf_load_stackoverflow)
GB (1) GB1021265A (enrdf_load_stackoverflow)
NL (1) NL280310A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3526459A (en) * 1968-05-20 1970-09-01 Dennison Mfg Co Optical illuminating system
US4131362A (en) * 1976-08-24 1978-12-26 Durst Ag Fabrik Fototechnischer Apparate Light-mixing compartment for a light projector
US4226523A (en) * 1978-11-17 1980-10-07 Energy Conversion Devices, Inc. Imaging device
US4608512A (en) * 1981-11-04 1986-08-26 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Lamp and reflector combination, particularly for projectors
US4716442A (en) * 1985-02-22 1987-12-29 Orc Manufacturing Co., Ltd. Exposure device and exposure control method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3526459A (en) * 1968-05-20 1970-09-01 Dennison Mfg Co Optical illuminating system
US4131362A (en) * 1976-08-24 1978-12-26 Durst Ag Fabrik Fototechnischer Apparate Light-mixing compartment for a light projector
US4226523A (en) * 1978-11-17 1980-10-07 Energy Conversion Devices, Inc. Imaging device
US4608512A (en) * 1981-11-04 1986-08-26 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Lamp and reflector combination, particularly for projectors
US4716442A (en) * 1985-02-22 1987-12-29 Orc Manufacturing Co., Ltd. Exposure device and exposure control method

Also Published As

Publication number Publication date
GB1021265A (en) 1966-03-02
NL280310A (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
EP0218178B1 (en) Infrared floodlight assembly
US3492070A (en) Illuminating system for a copying apparatus
US4000407A (en) Combined infrared filter and light focusing apparatus for a mercury vapor lamp
US1895887A (en) Incandescent electric lamp
US3021422A (en) Photographic light unit
US3241437A (en) Lamp house for photographic enlarging and printing devices
US20050115498A1 (en) Reflector for UV curing systems
US3720822A (en) Xenon photography light
US2117754A (en) Photographic enlarger lamphouse
JP3589856B2 (ja) 光インテグレータ
US2530843A (en) Photographic enlarger
US2466430A (en) Construction for projection lamps
US3498714A (en) Gas discharge lamp
US3375361A (en) Optical illumination system
US2195392A (en) Projection apparatus
US3860335A (en) Optical system
US3251984A (en) Illumination optical system for aerial photography
US4255045A (en) Removable light box
US3255345A (en) Light fixture
US3756719A (en) High efficiency integrator box
US3157362A (en) Device for producing a strong photoluminescent light
US3272067A (en) Copying apparatus
US2690106A (en) Printing lamp and cylinder cooling means
US3371575A (en) Illuminating apparatus for photographic enlargers provided with interchangeable integrating bodies
US3539258A (en) Optical apparatus for document copier