DE1447505A1 - Process for making multicolor copies of transparencies on photographic material - Google Patents

Description

Dl. E. WIEOAMD

MONKS

DIPL.-ING. W. NIEMANN

HAMBURG PATINTANWXLTI

MÖNCHEN 15, 24 October 1965

NUSSBAUMSTRASSE 10.

TELEPHONE, 555474 1447505

+1. 11 570/6;> 7 / Gö

ra! limited
Ilford, Essex (England)

Process for making historical copies of transparencies on p

era J- ¹ Ia tor ial.

The invention relates to the production of photographic copies and, more particularly, to copying of photographic multi-color transparencies through optical projection on a photosensitive copy material.

^Λ Γοηη Hehrfarbenentransparenie and, in the bosondersn test negative, copied onto a lichtenofinrlliches I-lehrfarbenentransparenie material, the relative exposures of the copy material against red, green and blue light

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be adjusted so that the copy is free of any unpleasant color cast after the color treatment. green and blt.-ue.Lt .Licit, which is used at the same time to expose the light-sensitive copy material . ^:: r f intensities of each. "various von.Farbnegative>" from a number density and Fnrbe '' - hen ^r a .photoelektrische Torrichtiuii · Jiessen to the intensity of each p.-Irbe hrinteveinyiider used; - /: i.ro, is the "iiinstiillunfr of the intensity ratio. through 3insohc-l ".un of color-selective filters'oeirr ntlhsriji. I> This is ^: änv- ^ uf , dii ;; filters used in all" l: -; - ei.ieino ^! N weekly IQi desires : - Absorption tend to be in de-ijeni ^ en bundles which they let through freely. So eriieu ^ t 'z.13. the ? ^: Iinsch £ ..ltung ■ fines Purpvirfiltez'e (Hagerit ^ filters) a Iversusetzung not only hinsiclitiic'ii C.ev Inteneiti't it ο grl-nen Lici "te, but also in the intensity of blue light due to the tin · rwvnnchten 3; -lsi.L8bp.o ">" ption practically verv- ^r emitted from purple jeglicler ¹ Similarly 1 / else a blfmgrLines filter (Cyaiifil ter) .grünes and blue light as well as can affect red..

^g AO ORIGINAL 809805 /, 05'19 ^ ¹ '·. ~

Achieving a satisfactory ratio of red, green and blue light intensities is greatly simplified if the ratio of the intensities of two colors can be assessed or fixed by a single operation. ^{T, r} hen a filter is adjusted in order to modify the intensity of light of a color is pulled its effect on a second color into consideration. ^T fonn the ratio of red and green light intensities is set by, for example one.

blue-green filter adds or removes. becomes the green absorption of the blue-green filter. The intensity of the blue light can be adjusted by dividing the blue-green filter be influenced, but a subsequent setting of blue light intensity through a yellow filter does not greatly disturb the red-green-intensity ratio, the has already been brought about. '

The advantages of measuring the ratio of intensities of two colors are already from Calkin, Hunt and Last one. (Photographic Science and Engineering, Volume 5, Ir. 6, Pages 366-373, November / December 1961). The Hittel, d'ie for bringing about this ratio measurement have been used so far, however, are quite inadequate. The method described by Calkin, Hunt and Letzer includes balancing the outputs or power outputs of two photocells. The insensitivity to a change in

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The intensity ratio is therefore the intensity level, at to which the color estimation or color determination is carried out, proportionally. Accordingly, the known method exists for use on the copy plane of a vertical enlarger not very suitable, since the intensity level of the copying plane increases significantly with the magnification which the enlarger is set varies the fluctuation of the sensitivities of practically used photocells from day to day is sufficient to Induction of noticeable errors when setting a required intensity ratio between 2 colors There will therefore be the application of a single phccelium preferred for the "estimation or determination of an intensity ratio of two! colors. Sine change in the Photocell sensitivity then does not affect the estimation or determination of the intensity ratio, provided that the spectral sensitivity of the photocell remains unchanged, i.e. the sensitivity to any wavelength remains in a fixed ratio to the sensitivity at any other wavelength.

When the photocell is used in a circuit arrangement which is a logarithmic relationship between · the electrical output or the electrical power output and the incident light intensity, the sensitivity is essentially independent of the magnification

\. . "". ■■ "... SAD ORIGINAL

tion of the enlarger. For example, light from two colors A and B can be dropped alternately onto the photocell, producing output voltages Ε »and E ^, respectively will. When the photocell currents correspond to the two

Colors I _A and L _n are and if the photocell has a current α ±> ·

proportional to the incident light intensity-supplies, then surrendered

^E A ~ ^E B ⁼ k ° ^{s 1} A - ^ ⁰ S%

The difference between the output voltages is so an indication of the ratio of the photocell currents corresponding to the two colors.

In practice it is not easy to have to determine:

whether E, or E_ is greater. Also the exact determination of A. ü

(E. - E) can be difficult if (E. _ \ passes through zero

Ά ■ ΰ A - -Ιίι-g /

It is therefore suggested that the photocell be continuous < to expose nuierlioh with light of the color A, but ·!

cyclic exposure to light of color B to under- j

ι break. The alternating or alternating component Ea in the . Output from the logarithmic amplifier represents (E /.. -R, \ - E, and is accordingly of constant polarity

- ^E (A + B). " ¹ A.- ^{Ιο§ (} -
** ' ^Λ - Log / I + ¹ I ,

so that if I ^ ^. I. /. _: ... . J

■ • Log ί ^ · nn, G! HAt IHSfSCTED

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1447506

This means that, provided that the response is ν to the cyclically interrupted height is never lower than 'ten times the. Responding to the not uttterJbrOQhe' - ne light, the output voltage Eq is directly proportional to the "logarithm of the ratio of the intensities or both

! Colors A and B. -.- * ^;

In the method according to the invention for the production of multi-color Transparent copies on photographisohem ^Hate-: rial, which are at least two, includes components, the selective to two different spectral bands sensitive, is allowed copying light onto a Phötozelle drop-on. "Cyclic into the path of . light, a filter on which ^one, but niohi of these spectral bands: can the ande-re "transit · conducts current from the photocell durch'einen logarithmic" - see amplifier ^1, the real tive light intensity em -in the two spectral bands to a set ratio which generates an alternating current component of a predetermined length in the output of the logarithmic Yorstapker and exposes the photographic material with relative intensity in the two; '. ^: ^ - \ Spectral bands in the set ratio »' ^: " · -. ■ * - ' ·,

In general, it is convenient to define the spectrum as in to look at three volumes split red, green and blue and ' two of these in the aforementioned method to The preferred pairs are Hot-Grtin and Red-Blue.

80'8β05- / Ο5 $ 8.

A combination of photocell and logarithmic amplifier is necessary for the successful implementation of the process required which have a precisely lograithmic response on incident light over a very wide range of intensities. It has been found that this Requirement is met by the circuit arrangement described by Hariharan and Btialla (J.Sei.Inst., 35 »Ho.2, Pages 69-71, 1956) described iwt.

According to a "particular embodiment of the invention therefore the photocell is of the electron multiplier type; it is at a substantially constant collector or Collector current operated, being part of the dynode supply voltage to the electron multiplier a log-withmic amplifier is pressed, one of the output of which AC voltage is obtained, 'which is a measure of the ratio of the light intensities of the colors in the two spectral bands use ^ will.

The invention is explained in more detail below with reference to the drawing and a special embodiment.

Üg. Fig. 1 shows a side view of the photocell unit and the associated color-selective pilter. · Pig. Figure 2 is a plan view of the same unit.

Pig. 3 shows the electrical circuit for the power supply ' tion of the photocell and the logarithmic amplifier.

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Pig. 4 shows the circuits for the AC power supply stronger and the measuring arrangement.

The circuit arrangements according to FIGS. 3 and 4 'represent a single circuit when the arrangement of FIG. 3 left to the one-of l ^? ig. 4 is set.

According to the figures, 1 and 2 must light which the ver. Reached multiple photocell 1 with side window, first go through the fixed color-selective filter 2 and the sector disk 3, which is rotated by the motor 4. The filter 2 is an Ilford yellow fliter ITo. 109, which therefore transmits the green and red components of the copying light, but absorbs the blue. The sector disk 3 rotates at 3000 rpm and comprises two transparent sectors 5 and 6 of 90 ° each and two sectors 7 and 8, also of 90 each, which are covered with IlfOrd red filter hoops 204.

When the disk rotates, hot light can therefore freely pass through the yellow filter 2 and the disk at any time and reach the multiplier photocell 1. Green light which passes through the yellow filter 2 is modulated by the rotation of the disk 3, since the sectors 5 and 6 Allow green light to pass freely while sectors 7 and 8 absorb it. It follows from this that the photocell alternately picks up red light alone and red light and green light on the slide side. This is the condition for the device which provides an indication of the ratio of green and red light.

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^! When it is required ,: the ratio of blue light to be measured to red light, the filter 2 in 'is the dashed line position 2a shifted and the purple filter 9 (Ilford ITO.' 502) ± n the working position pushed, previously from the Yellow filter 2 was ingested. When this is done, the purple filter prevents green light from reaching the photocell. Blue light that goes through the Mage & tafilter 9 "is then modulated by the rotation of the disk 3, while red light is the photocell in the

·. ". Achieved essentially without modulation.

The current emitted from the cathode of the photocell 1 includes a direct current component that the unmodulated red light intensity, and an AC component of 100 Hz (c / s) corresponding to that modulated green or blue light, which the cathode • achieved. The photocell ^ is connected to the circuit arrangement shown in Fig. 3. This circuit corresponds essentially of the order given by Hariharan and;

·. / Bhalla is described, (ie), The circuit arrangement · the. 3 continuously regulates the amplification of the multiplier photocell, so that the collector or "collector" current of the photocell is essentially constant at any moment. To achieve this, the ./photocell: supply voltage becomes in accordance with the intensity of the.- ■ ■ -. .

incident light changed. Are part of the Phctozellenzia? - ·. Is \ drove pari voltage through a current limiting resistor i

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- ίο - .. '■■ ■■' ■ '....

-an the grid. of the tubes V7, which, as logarith-. j ■ · mixer "amplifier: works. Hariharan and Bhalla have -ge-. shows that the output from this amplifier is logarithmic Puncture the light intensity falling on the photocell over a range of intensities of TQ x 1.

The AC component of the output of the logarithmi -., / .., see amplifier is, to the grid, of the tuned ver-r, stronger V8 applied. The anode charge of the amplifier ^ bes, arises from a stream that is reduced to the basic frequency. it is true, with which he the green or blue light under -, - ' will break, namely 1.00 jpz. Yon that. tuned amplifier goes the 400; Hz signal to a negative Bü'okk coupling amplifier, which comprises the tubes V9a and .V9b.-The. . AC output this amplifier is made by: the- diodes MR3-'and M4 rectified ,, s. Ö / that. at R31 'a constant voltage is generated which is proportional to the AC power supply of.amplifier.with negative: feedback is. The cathode amplifier VTOa applies this track voltage: a; Page: des. measuring instrument M * The second cathode amplifier V1Ob. lays. at. the other side of the .meter, a -potential ;; an, ·, which is determined by the setting of the potentiometers RV7 and / or RV9- ■■ .- · '' - · ■;: / .; ·> :; ..: a

- ■ If that; Instrument «a logarithmic series includes ^ the Pbtentiamevfeer -; - RV7v EVB xmä aren'Sscales in values-of;

the. Thus, the "green" control RIQ can be calibrated so that it indicates positions which maintain a given deflection on the measuring device M when weak green absorbing (purple) filters of equal strength are in the path of the light reaching the multiplier photocell 1 , can be used. Suitably correspond to the portions between the marks of the consecutive addition of filtering a G-rünlichtintensität of 0.05 · In ähnlioher manner, the "blue ¹¹ -control with RV9 in parts of

'i

Yellow intensity and the "Eot" control in parts of blue-green intensity marked. In an application example, several test copies can be made from a particular test negative using various combinations of weak color correction filters, green-blue, purple and / or to be made yellow. When these copies have been color treated it is generally possible to use the combination of Color correction filters to determine which is a satisfactory one Result from the particular test negative. ,

The controls RV7, EV8 and RY9 can now be set in this way that they correspond to this combination of filters. ■

If any other negative is to be copied, the instrument can be used to make the combination display of J color correction filters that is required a satisfactory copy of this other negative

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to create. The negative to be copied is first inserted into the '-. Enlarger with the combination of color correction- ' filter brought ,,. selected for that, trial negative .. Suitable light for copying is applied to the photocell unit dropped ...] 3as .yellow filter, and-the pur- · purfilter. (2- or -9) are ..then in the in · Pig. 2 shown Position brought, i.e. the yellow filter 2 in the working position above-the multiplier photocell 1. ¥ enn the switch S1 is in the position shown in Fig. 4, is now the green-red-nill control RV4 set so that daii the display of the measuring device is on full, which means equality in the potential, the cathodes VIOA and "Vloli" is displayed. The 'yellow filter 2. Is now in that shown with 2a in Fig.2 Position moved and the purple filter -9 is jLn Ar-. brought into position above the photocell 1. The switch £ 51 is now moved to the other position and the Blue ^ Rpt-Mull control HV5- is set so that the Meter. ^ M returns to full display.

The negative to be copied is now replaced by the test negative, 'far as the yellow filter -o is in the working position-and the switch 61 is in the specified position, the green control RV8 can be set to the. Heß-; to bring device H back to the lull display - the yellow filter. 2 is now removed from its working position and the purple filter 9 is replaced and the switch 81 is

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Moved to the other position ". The ^M blue" control EY9 is now set in order to bring the measuring device M back to full display. The new combination of settings for. RV ?, RV8 and RV9 now "immediately shows the combination of color correction filters required to produce a satisfactory copy of your negative to be copied.

Under certain circumstances, it is found that, in order to return the measuring device M to the level display, it is obviously necessary to use one of the two controls 3V8 or IiV9 ä'u e.htor iio ₀ - <: .. t: b / ert J \ i < y, el _t ν -, - ν Crehta * -. Since this is not possible in practice, the control in question is set to BTuIl and RV7 is set so that the measuring device M is brought to full display. If RV7 is set in this way after RVS has been set In order to adapt it to the negative to be examined »it is then necessary to - return the old ■ 2 to the working position, return switch S1 to the specified position and set RV8 again.

A modified method of using the device involves setting the controls. RV4r BV5, RV7, RV6 and RV9j as described above, so ate the meter returns a zero display if either the yellow filter or the purple filter in its working position in front of the multiplier photocelia and Sl in the appropriate corresponding place

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ment are. If this result for the particular search negative and the combination of color correction filters which If a satisfactory copy has been obtained, another negative can be used instead of the trial negative can be used. The I color correction filters that are used in the housing (lamp house) can then adjusted until the measuring device M shows full again, either with filter 2 or filter 9 in working position and with switch S1 in the corresponding state described above. ''

In Fig. 3 the controls HV1 and RV2 are provided, ; to allow the operating conditions of -'V7 to be set to have a logarithmic response over the widest possible range of cell supply voltage is delivered. '', - "■". "

In Fig. 4, the control RV3 sees a setting of the Degree of negative feedback - those in the feedback amplifier Y9A and Y9B is used before. She regulates that Amplification of the amplifier and therefore the sensitivity, of the instrument. ^ -:

RV6 regulates the current through the Poten.tiome _: terkette, which is formed by RV7, RV8 and RY9. By setting:

■ - · ■■ - ■■■■ '■ ■■■■' ■ ■ !, '■' * ·

· 'SV6 makes it possible to adjust the sensitivity of the _: controls.;' .. '., RV7, RVS and RV & so that they match the sensitivity of the instrument. ",,,

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: ..- In order to limit the response of the photocell 1 to the appropriate spectral bands, preferential

wise a didymium glass filter (2-mm from Ohance OM 16) in the. The path of the Mclrts reaching the photocell is set.

It can be seen in connection with the above description of the device that. a photomultiplier . (VervjLelfaoherphotQzelle) a combination of a photocell with an external borrowing feeLectric effect and an electron multiplier, which is contained in the same shell, represents. The electron multiplier is essentially a linear current amplifier, but it can be used in connection with known arrangements of other circuit components form part of a logarithmic amplifier that is about a dynamic range of 10 - 1 works:

The following is a list of the parts shown in the circuit arrangements of Figures 3 and 4,

Reference symbols in the circuit diagram or designation

■ ■ ■. ^; R1 5 k "R2 47 k R5 47 k R4 10 k R5 15 ohms - R6 . 330 k ■: - • 47 k R8-R15 8 χ 47 k ■ R16- ■ 100 M. R17 10 k ^: ■ "·" RI 8 ^; "· ■ 30 M'- R19 4.7 k R20 100.k

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Reference symbol in the circuit diagram ^T fert or designation

V R21 "· j ■ "- ■ 5 ohms V. R22 1 M. \ 'R23 330 onm R24 "■ 1.5 k ■ R25 5 19 68 Ok R26 4.7 k R27 22 k. R28 47-k. · ■ R29 4.7 k R30 1 ii -. R31 1 M. R32 47 k: - ■ ■. . ■ R33 100 k R34 100 k ■ - ■■ -. R35 100 k RY1 10k RY2 10 k R.Y 3 2 N ^: * RY4 10OK ■ RV5 100 k.-.- ■■ RY6 250 k RY7 66k- + 66 Ic RY8 136 k RV9 ■ 136 3l 01 1 / λϊ ¹ 02 1 μΈ 03 • 0 ^ 1 / ΐΤ 04 0.1 '/ -Ψ 05 16 / Φ (electrolytic) 06 0.2 ι® - 07 2 03? 08 1 } ul? 09 0 ^ 1 .ftP 010 O, Of / Φ 011 "4 ^ iF (^ lektroljrtisoh) 012 0.5 iü? MR1 Rectifier MR2- Rectifier MR3 . "" "Zb 74 (rectifier) - MR4 ZS 74 (rectifier) Y1 Qfi 75/20 Y2 90 cl. · Y3 EJ, 360 Y4 Bl? 86 ■ . Y5 931-A. Y6 108 oil Y7 IiGG 83 • · Y8 BL 9 ^: 1 V ₉ 809805/0 BCC 82. · Y10 ECC 82 • 11 12 K (jirossel) M1 50-0-50 / 4 / (Heuser) 'S1 . Two-pole changeover switch

Claims (7)

Claims 1.J Process for making multicolor copies of transparencies on photographic material, the least contains two components that are selectively sensitive to two different spectral bands, thereby characterized in that one copy light onto a Phabo cell drops, a filter that passes one of the spectral bands but does not pass the other, cyclically into the ¥ eg the light turns on, the current from the photocell through a logarithmic amplifier, the relative light intensities in the two spectral bands on Ratio sets which in the output of the logarithmic amplifier an alternating current component of predetermined Amplitude generated, and the photographic material exposed to Kopler light, the relative light intensities in the two spectral bands. in such a set relationship. ■ · 2. The method according to claim 1, characterized in that that an electronic multiplier uses photocell and with an essentially constant collector or collector current is operated, with part of the dynode supply voltage of the electron multiplier at the logarithmic applied more strongly and from the delivery of the logarithmic 809805/0519 144750S stronger an alternating voltage · is obtained, which is a measure of the ratio of the light intensities ^: the colors in both spectral bands. '-'"/"'' ■ ^{; :;} · 3. The method according to claim 1 or 2, characterized in that that the pre-determined amplitude thereby `` coincides '': ensures that you get the best possible copy of eiriem ** · .- ■ - transparent multi-color negative produces the special ■ combination of color filters iöt- 'necessary to obtain ^one such copy, determined and PobentiometerkontrolTen that are a öleiehstromq.uelle Connected - as ^one! 'represents that the rectified alternating current ^{component *>:} the output of the logarithmic amplifier is equal to · the ^; Off ^; The potentiometer would be if Köpierlxeht that through - "" ■ "-. 'the combination of filters goes to the photocell" falls. · 4. The method according to any one of claims 1 blä 3VOa- ^ _; characterized by that -the spectral bands are red and / green. , ' • 5. ·: Method according to one of the claims. 1 to 3 »thereby characterized in that the spectral bands are red and blue. '~' 6, method according to one of claims T to 5, da.-dur.ch characterized that a didymium glass filter in the ¥ eg the copy light that reaches the photocell * is brought, the response of the photocell to the called the spectral band anyway, ■:. ■. '■■' BATHROOM ■ 7. Apparatus for carrying out the method according to claim 1 with a photographic copier, characterized in that it has a device to copy light, which comprises two spectral bands, fall on a photocell with electron multiplier, which is electronically controlled so that it "at im essentially constant collector current works, a device to switch a color filter cyclically in the path of the light, the light from one of the spectral bands, but not from the other, a device for guiding part of the dynode supply voltage of the electron multiplier to the logarithmic amplifier. , means for adjusting the relative proportion of light in the two spectral bands which reaches the electron multiplier and includes means for measuring the magnitude of the current in the output of the logarithmic amplifier. 809805/0519