US2446112A - Method for making test prints on color print material - Google Patents

Description

July 27, 1948.

Original Filed Aug.

Fig: l

A. SIMMON ET AL METHOD FOR MAKING TEST PRINTS ON COLOR PRINT MATERIAL 15, 1946 6Sheets-Shet 1 Jul 27, 1948.

A SIMMON ET AL 2,446,112 METHOD FOR MAKING TEST PRINTS ON COLOR PRINT MATERIAL Original Filed Aug. 15, 1946 6 Sheets-Sheet 2 I .5 mm mm 4 July 27, 1948. A SIMMQN AL 2,446,112

METHOD FOR MAKING TEST PRINTS ON COLOR PRINT MATERIAL- Original Filed Aug. 15, 1946 6 Sheets-Sheet s I02 lo [05 88 w s T a a mm W A M r ,M M J y 27, 1948- A. SIMMON ET AL I METHOD FOR MAKING TEST PRINTS ON COLOR PRINT MATERIAL Original Filed Aug. 15, 1946 6 Sheets-Sheet 4 July 27, 1948. slMMON ET AL 2,446,112

METHOD FOR MAKING TEST PRINTS 0N COLOR PRINT MATERIAL Original Filed Aug. 15, 1946 6 Sheets-Sheet 5 3 Wu Wm;

July 27, 1948.

A SIMMON EI'AL METHOD FOR MAKING TEST PRINTS 0N COLOR PRINT MATERIAL Original Filed Aug. 15, 1946 I Sheets-Sheet 6 a 43 III 7 m5 w I 50 w a rww I v AID. Z, 0 0 o o Patented July 27, 1948 METHOD FOR MAKING TEST PRINTs oN coLoR PRINT MATERIAL Alfred Simmon, Jackson Heights, and Louis L.

Weisglass,New York, N. Y., assignors to Simmon Brothers, Inc., Long Island City, N. Y., a corporation of New York I Original application August 15, 1946, Serial No. 690,688. Divided and this application April 25, 1947, Serial No. 743,948

transfer type, respectively. In the monopack, a

plurality of sensitized emulsions, usually three, are coated on .a common base. Each of these emulsions is sensitized to one primary color, only and is adapted later, during the processing of the monopack, to be dyed with an appropriate color. Distinguished herefrom, the separationtransfer process necessitates the making of three separate prints, usually from three separation negatives in the three primary colors, on three separate sheets. During the processing these sheets are developed, dyed in appropriate colors, and eventually all three images are transferred to a common base. It is the particular purpose of this invention to provide a method for the testing ofrcolor print material of the separationtransfer type.

sensitized material for ordinary black and white photography is usually tested by making a so-called stepwedge print. By a stepwedge' print we generally understand an elongated strip of such material divided into a fairly large number of small rectangular areas which are subjected.

in some manner to a steadily increasing or decreasing exposure to white light. The relative densities obtained by this method enables one to judge the properties of this material.

The application of this principle to color print material is not quite simple since it is not suflicient to make, for example, three stepwedge prints with the three primary colors, respectively, because for really complete information it is necessary to provide some means by which one can obtain areas which are exposed to any conceivable combination of three respective exposure times for the three primary colors. In order to do this, we replace according to this inventioneach rectangular area of a stepwedge print by a triangle which is being exposed non-uniformly to three part exposures with the three primary colors,

respectively. Each corner of the triangle receives portion to the distance of each point from said I side of the triangle. A triangle exposed in this manner will show the three corners in more or less bright colors, usually red, blue and green. The luminosity of these colors diminishes gradually as the center is approached, and the center should show, with a well balanced material, a neutral gray. If the exposure times to which each point of the triangle has been exposed for each color increases in linear proportion from each side of the triangle to its opposite corner, the sum of the three exposure times will be constantover the entire area of the triangle. An infinite number of such triangles is conceivable, depending upon the magnitude of said sum. In reality, of course, we have to compromise and be satisfied with a relatively small number of triangles, but

even a small number will give adequate information about the behavior of the color print material if the sum of the three exposuretimes for each triangle follows a suitable, usually geometric, progression, and if thereby a sufiicient range=of exposure times is being covered. 1 According to this invention, we subject consecutively on three separate sheets of color print material to be tested, a plurality of triangular areas on each sheet to non-uniform exposures of varying lengths. For purposes of ready identification, each triangle is supposed to have an A, B and C corner. The triangles occupy identical positions on the three sheets and the A, B and C corners of corresponding triangles occupy identical positions. All triangles on the first sheet are so exposed that the FA" corner receives full exposure and the side opposite the A corner receives no exposure, intermediate points receiving intermediate exposure values in dependence upon their distance from said side. While thus all A corners receive full exposure, the length of this exposure varies from triangle to triangle. On. the second sheet all 3" corners receive full exposure, the sides opposite the B corners receive no exposure and intermediate points receive intermediate exposures."

subjected to the same treatment with respect to the C corners. Exposure values are assigned to various triangles on all three sheets in such a manner that the A corners of each triangle on the first sheet receive the same exposure time as the B corners of the corresponding triangles on the second sheet and the C corners of the corresponding triangles on the third sheet.

The three sheets, after being exposed in the manner described are then subjected to the customary chemical treatment, usually including development and possibly fixing. The image, which is usually, but not necessarily, composed of precipitated silver is then, by one of the several processes well known in the art, replaced by a pure. dye image, the three sheets, of..course, receiving dyes of three different .colors; -generally three primary colors, i. e., r'edp-blue and-green are used, or the corresponding complimentary.

dye images are then transferred to a common l paper base and superimposed in such a manner that corresponding triangles are in register with each other.

Theiresult is a test sheet with anumber of tritzangular exposures. .The A? corner of each triangle.- appears, for example, red, the B corner blue. and-the C corner green, and in a well balsanceddc-olor material the :center of the triangle :willbe .a :neutral gray. The. exposure times for ":-thethree corners are equal to each other, but .:.vary from triangle to triangle and, therefore, -while all A corners appear red, all B corners iablue and all C corners green, these colors will .sbe lighter or darker from triangle to triangle, dependingupon the predetermined variation of ex- 121308111 6 times. .For example, the first triangle eimay be almost entirely black, showing merely :some .very dark traces of red, blue and green, re- -ispectiye1y,.in thecorners. The .next triangle will bewsomewhat less .dark, and the corner. will be :zmore vividly colored, and one of the subsequent l=:triangles may show really luminous-colors. From 'lthenwon, onsubsequent triangles, :the colors will .begin'to .fade ;until the last triangle is almost completely white, with perhaps a slight color tinge in the corners. I

a "For a better understandin of the method, .the ,subject .of this I invention, a preferred embodiment iofsa device to practise it is illustrated in the accompanying drawingsand described in this specification. Y i

In theldrawings,

1 is a cross-sectional view through the-deavice, :the working position shown in solidrlines and thepositionin which a new sheet of material cc'an-be insertedsh-own in dotted lines; Figs. 2 and 3 are views in the planes of lines #2-2:and 3'3, respectively, of Fig. -1, showing essentially the configurations of two cams;

. i Fig; 4 is a viewin-the plane of line ,4- l :in Fig. "1, showing the motor drive for said :carns as well and at the end of anzexposure, respectively;

Fig. 6 is a view in the plane of 'line.6B;of Fig.

l 'showing essentially the rotating and indexing "support'for :the color print material;

Fig. '7 is a cross-sectional .view along the plane of line 1-1 as shown in Fig. 4;

.1 p g n aperture plate, the purpose ofwhich will be'explained later; and

4 Figs. 9a, 9b, 9c and 9d are schematic diagrams of the test print obtainable with this device.

Like characters denote similar parts throughout the several views and the following specification.

General design The preferred embodiment of the device comprises a supporting structure made of two principal parts, the base and the hinged top, The base carries a support for the color print material including means to rotate and index this support between exposures. The hinged top carries an indexingland rotatable table on which are .mounteda motor drive with a train of gears, a cam assembly actuated by said motor drive, and .aimasking slide with a supporting lever assembly. One of the cams actuates through that lever assembly saidmasking slide, and the second of said cams actuates said aforementioned rotating and indexing: means sfor the support for the color :printmaterial.

Base

The base is shown in cross-sectional view in Figs. 1 and '7 and its outline can be seen in Fig. 6. It comprisesa-flat plate 20, preferably made from aluminum or the like, to which certain other elements are attached. These other elements are lugs 21 which support the hinged top to beadescribed in one of the following paragraphs .and a shaft 22 which serves as a pivot for the rotating and indexing support of the color print material.

. Support for color print material This unitis shown cross-sectionally in Figs. 1 and 7 and a plan view is seen in Fig. 6. his supportedbythe aforementioned pivot '22 which is surrounded by a hub'25 carrying a rectangular plate 26, preferably made from sheet aluminum. The size of this part, shouldpreferably correspond to the most readily available size of color print material, and for that reason the dimensions '8' x10" are usually chosen. Means must be provided to attach a sheet of color print material to the upper surfaceof plate 25, Since spring clips or the like are well known in the art, these means have, in'the interest of clarity, not been shown in detail in the drawings.

Fastened to the upper surface of plate .26is a .ratchet gear 21 which carries a plurality of ratchet teeth 28", 28 and so forth. Means are provided to urge plate ZBand ratchet gear 21 .to rotate. 'These means may be of any desired description and, .for example, 'a small electrical torque .motp'r may be used. Merely as an example, we are showing a torsion spring 29 of; the kind usedin large clockworks. One .end of this spring 29 is attached tothe ratchet gear 21, whereas the .other end 29'' is attached to a stud .30 which is, in turn, fastenedto the base plate .20. Thisspring urges plateZE to rotate in .a counterclockwise direction. It is, of ,course, necessary that the operator turn plate 26 at least once in a clockwise direction before starting the exposure, thereby vtensioning the spring.

The rotatable assembly comprising parts 26 .and 2 1 is restrained by ratchet 3| pivoted on a shaft .32 which is,...in turn, supported by base plate 20. This ratchet 3i has two ends, one with a hook like-shape 3| and another one 31'. It is .biasedbya small spring I32.

Asolenoid 33, comprising in-the .usual manner -.a.zcoil and .a .movable armature, is attached to perform a rotation of 60.

base plate and connected by means of link 34 to-the ratchet 3|.

By viewing Fig. 6, it will be clearthat as soon as solenoid 33 is energized, one

arm 3|-of the ratchet 3| is retracted, permitting tooth is of the ratchet gear to pass. At the same time, however, the other arm 3|" of the -of tooth-28", thereby stopping the rotation of the ratchet gear 21 after another 30.

In other words, every time solenoid 33 receives a current impulse, ratchet gear 21 andtherewith plate 26 The rotation of 60 is, of course, merely by way of example and any other angle may be chosen if so desired.

-As can be'seenin Fig. 6, the axis of rotation ofsupport Z6 coincides at least substantially with one of the corners of .priSes a horseshoe shapedpart 40, the outline of .which can be seen in Fig. 6 and which is, preferably, fabricated from an aluminum plate. On

one side two lugs 4| are attached which cooperate with the aforementioned lugs 2| attached to the base to form a hinge. Shoulder screws 42 are fastened to lugs 4| and permit, in the manner visible in Figs. 1 and'6, the rotation of the hinged top.

Fastened to the hinged top are three studs 43, 43" and 43,.each of whichcarries agrooved roller 44. The studs 43 and the rollers 44 are also visible in Figs. 4 and 5. It is the purpose of these rollers to support the rotatable table to be described in the next paragraph.

Rotatable table The cross-sectional view of this table is seen .in Figs. 1 and 7; 7 It comprises a round plate 50,

theqcircumference of which is machined so as to fit into the groove of rollers 44 as can be observed at the left side of Fig. 1. Referring to Figs. 4

and 5, thistable is equipped with a mark 5| by means of which its position can be readily identified. .As shown in these figures, the mark points at the center of the left roller supporting stud .432. Since thetable can be freely rotated, it can bereadily positioned in such a manner that this mark will point to the center of either of the two other roller supporting studs 43 or 43".

a As can be seen in Figs. 4: and 5, the axis of rotation of the rotatable table coincides with the center of the triangular exposure area. 52. This center is the point of intersection of lines connecting corners of the triangle with thecenter points of the respective opposite sides.

. In the center of the rotatable table 5!], we have a triangular aperture 52 as well as an elongated slot of peculiar shape 53. It is the purpose of the triangular aperture 52 to admit light to the exposure area, and the elongated slot 53 is provided for the purpose of permitting a mechanical con nectionbetween the masking slide and its supporting lever system; to be described later. 7

.Mounted below table 50 and separated there- .from by relatively thin spacer-s 54, see Fig. *7, is an" aperture plate 55. which again is shown separatelyin Fig. 8. This aperture plate has a triangular aperture 56 which has the same dimensions as the corresponding triangular aperture within table 50. The aperture plate is mounted so that the two triangular apertures arein the same position. As can be seen in Fig. 7, the table 50, the spacers 54, and the aperture plate 55 form a channel in which the mask 60 can slide.

Mounted on the rotatable table 50 are the masking slide and its lever assembly and'the rotating cam assembly comprising two cams and a motor drive including a train of gears.

Masking slide and lever assembly The masking slide and the lever assembly can most readily be seen in Figs. 5a and 51). Certain features, such as the hubs of certain levers, are shown in Fig. 7. l l

The masking slide 60 itself is shown in dotte lines in Figs. 5a. and 5b, one of these figures representing the position of the slide at the beginning and the other the position of the slide at the end of the exposure. This slide is positioned underneath the rotatable table 50 and is supported by two studs 6|. These studs are somewhat longer than the thickness of table 50, and protrude through the: aforementioned slot 53. Fastened to stud 62 are two levers 63 and 64 whichform a parallelogram movement whereby the masking slide 60 can be moved parallel to itself in a flat are closely approximating a straight line. Lever B4 is pivotally supported at its other end by a pivot 65 which is stationarily fastened to the rotatable table 53. This lever isbiased by a spring 66. The other lever 63 is fastened to a relatively long hub 61 which rotates on a stationary shaft 68 which is again fastened to the table 50. of hub 61 carries a relatively short'lever 69 which can be seen in Fig. 2 and which constitutes the cam following element in operative engagement with the cam shown in Fig. 2 and tobe described in one of the following paragraphs. The assembly of lever 63, hub 61 and lever 69 can be seen inFig.'7.. w'

The exposure of the triangular area can be achieved in two different ways. We can start with a triangle fully exposed and cover or mask its area gradually during the exposure time, covering one of the sides of the triangle first and the corner opposite saidside last, or we could reverse the procedure and start with the triangle completely covered and expose the corner first, adjacent areas thereafter, and the side opposite said corner last. The two methods are perfectly equivalent and merely as a matter of example, we have chosen in our embodiment of this invention the latter method. After the triangle has been completely exposed at the end of a part exposure, theexposure must, in theory, be terminated instantaneously and, in practice at least, very fast. This can be done, for example, by switching off the lamp from which the exposing light originates, but in the interest of simplicity, we merely permit the masking slide to return quickly, and this is the reason why the lever 59 is not equipped with a cam following roller, but merely with a knife edge since, in this manner, a more rapid return is possible than with a roller.

M otor drive The upper end i accents havera speed of'3,;600 R. The-shaftof this engages a second wormgee-r85. The ratios of the two worm gear assemblies; are: 1430. each.

Fastened: to worm. gear 85:is=a small spur. gear 86. 'Iihetwogears 85 and. 8G rotate as a unit on a stationary.- pivot'fil which is fastened; to table 50. The small spur gear 86: is. inmeshwith a large spur gear 88 which: rotates on. a large hollow shaft 89. This shaft is supported by aspacer 90 which, in turn, is fastened to table 50'. A crosssectional view of the spacer '90 can be seen in Fig; '5". It. is of general cyli'ndricalshapabut part of: its: circumference is cut awayxin order to per mit the movement of the levers 63and564;

The ratio of spur gears86= and"8-8: is-1:12. To-

gether with the two worm gear assemblies which have a ratio. of 1:'30 -each,.this gives: a total ratio .of 1::'10,800, or the two cams make in' this particular example, one revolution.- in three: minutes.

Cam assembly The cam assembly canbe seen cross-sectionally in Figs. 1 and '7. The shape-f the two cams is I shown in Figs. 2 and3.

The cam assembly comprises, inadditionto the largespur gear 88-- which was already mentioned, two cams. Hill and I IJ.-I supported. by spacers I02 and H13. 'Iihe two earns, the spacers and. the large spur gear rotate asa unit on the large hollow shaft 89.

Cam I00, shown in Fig. 2; is substantially circular in. shape and I carries' on its circumference a number of spiral shaped. abutments. LII], I II, H2, H3, H4 and: H5. The shape 0t these-abutments is determined" byspirals which are. of; the type that hasalinear equation in a system. ofpolar coordinance, i. e., the. radius increases in linear proportion with. the angle; these spirals aresometimes called Archimedes spirals. Theradial increment. of all spirals is the. same, but is distributed over difierent angles. For example; the shortest abutment III]. occupies-an-angle of 12. The following abutment III has-an angle of. 18,

- andthe longest. abutment H5: has; an angle of 120*. The. angles occupied by these spirals increase: substantially inv geometric progression,

each angle being approximately, 1.6.times as large operation. Between subsequent cam abutments there is-a gap of 7, where the-cam circumference has-a constant radius. During. these gapsthe maskingz-slide will. be stationary, and time is ,thereby provided for the rotating and. indexing of the support for the photographic color print material. During operation; cam: IBIhrotates-in thedir-ection of arrow. I515.

The second cam is shown in Fig. 3. This cam is circular in shape and carries a number of small projections I 20. Bycomparing the shape of cams IEiIl-and I-ll'I; as shown inFigsHZ: and 3, itcan be seem that theprojections. Ifll! of cam-v Hl-I are.- so

, disposedithat they.- fallibetweengapsofthe.- spiral shaped-camabutment ofcam.- L00. It is the'purpose. of cam IM to actuate therotatingl-and in;- dexing support for the. color print-.material.-de.- scribed in. one of the preceding. paragraphs and shownin Fig. 6.. This is: not; quite. simple: dueito the fact that the supporting. table' 50-itself on which the entirecam assembly withwits'metor drive is mounted, is adapted to assume various positionsbyrotation. While a-purelymechanical connection is conceivable,. it is apt tor become somewhat complicated, and. we prefen. therefore, to. connectthesetwo elements. by electrical means.

These. means comprisaa switchain: operative contact with cam. IM anda solenoid fl in.operative contact. with the rotating and-indexing movement of thesupport for the color printtmaterialt The latter has already been described and. can-be seenin Figs. 1 and- 6.

Referringagain to Fig; 3,.a switch. I21 is shown operated. by the cam abutment. I-.2Il.-of-.eam.-.I2 I. This switch-is shown to be of the so-calledmicroswitch type, but it can, of course, beef any other desireddesign. It carries, preferably, acam-following roller I-22 which is. alwaysin contact with the cam IUI. The switch is supported byastud I23, see Fig. 7, Which'is fastened to the rotatable table 50. This switch is connected in series with a-source of electricalcurrent-and thersolenoidi 33, andsuitable means" such. as flexible. leads: are provided for' this purpose; these flexible" l'eads have-not been shown on the drawings. It'w-ill be clear-that whenever cam- IOI-",. during itsrrotation; brings-one of its. abutments" I20 in contact with roller I22, theswitch which is normally open becomesr CIOSGdtfOI" an instant and',.ttherefore,- solenoid.3direcciyesacurrent impulse; This, in the previously described manner, actuates th'e escapement movement. which. governslth'e rotating and indexing movement. of the support-for the color print: material.

Operationand method of making test;printsv The operation of the device'is:v as follows? Before the start-.of a. test exposure, the hinged top is lifted, as shown in Fig. 1 in dotted lines. The rotatablepl'atform' 2'6 isat'henturned at-least once by hand in'a clockwise. direction, whereby the spring. 29: is tension'ed'. Aasheet ofithet color print material to be: testedl is: then. fastened t'o thisplatformlt; and thehinged' top is permitted to assume its operatingJposition, asshown-imliig. ii in; solidilines. It: is assumeditha't the two: cams at this time: have the-relative positions, as shown in Figs- 2 and: 3;. If the cams 1v are not 'in'tl'i'eir starting position, it ismerely necessary to let motor runifo'r awhile andstopdt-at the proper 'lightfor thispurpose-is an ordinary photographic enlarger, in: which; case the. test; device is merely placed on the-easeliofthe-enlarger; The;- motor is thenstarted and the: operation. begins; The first abutment I I flofscam: IIl-I] actuatesaby: means of. lever I59, hub. 61' and levers. 63 and 643..the

masking. slide: em. Atv the: beginning of the exposure this. slide covers the exposure 1 areacompletely, i. e., it has the position' showmimFlgafia. During; the expos-ure'it: moves from right tosleft, uncovering; the Af' cornerwof' the triangular exour example will, therefore, ,equ-al six, seconds.

This means that the A corner of thetriangle receives the full six second exposure, but due to the masking effect of ;the. slide, the side opposite this corner will receive no exposure and intermediate points will receive intermediate exposures.

The cam I 80 continues to rotate and lever 69 will rest for a short while on the circular portion of the cam between abutments I I and H l. During this time, the masking slide will be stationary.

By comparing Figs. 2 and 3 it will be seen, however, that at this time the cam abutment I 2|] 0f cam [0| will depress the cam following roller I22 of switch IN. This switch which is normally open will, therefore, be closed for a short period of time and solenoid 33, visible in Figs. 1 and 6, will, therefore, receive a current impulse. The solenoid actuates the escapement movement consisting of pivoted lever 3i and ratchet gear 28 permitting this ratchet gear, in the manner described above, to rotate by 60 in two steps of 30 each. The rectangular platform 26 to which the color material has been fastened will perform a like rotation and will, therefore, present during the next exposure a different triangular exposure area to the source of light.

The next exposure will, in all respects, be identical with the first one except that cam abutment Ill comprises an angle of 18 instead of 12 resulting in a correspondingly longer exposure time. After cam abutment III has passed there is another gap of 7 provided on cam I00 during which the lever 69 and, therefore, the masking slide 60 remains stationary. During this period another projection of cam lfil will close the switch, and by means of another current impulse, energize the escapement movement of platform 26, causing it to rotate by another 60.

This procedure win be repeated until platform 26 has performed a full revolution and until, in our example, thereby six triangular exposure areas have been exposed in the manner described.

The device is then stopped, the top is lifted, the exposed sheet removed and a fresh sheet inserted. The spring 29 urging platform 26 to rotate may, at that time, be tensioned again should this prove necessary.

At this point the entire table 50 with all the mechanism carried by it must be rotated by 120. As shown in Figs. 4 and 5, mark 5| points at the stud 43' which supports tabl 50. After table 50 has been rotated 120 this mark will, of course, point to one of the other studs 43", and it will remain in this position for the exposure of the second sheet of color print material. The exposure of the second sheet of color print material is in all respects the same as the first exposure, except that due to the 120 rotation of table 50, different corners which we may call the B corners of the respective triangles will be exposed.

After the second exposure cycle, the device is again stopped and the exposed sheet replaced by a fresh one. Table. is again rotated.;"-;and

the third exposure cycle is performed in thisposi-v tion. The third. exposure cycle equals the two preceding ones except that, of course, now-all ex posures, begin atthefC corners of therespective triangles. i

The three sheets are then developed and, after development, will have anappearancewhich is schematically shown in Figs. 9a, 9band19c. In Fig. 9 all A; corners areshowndarkened. They will, in reality, be, ofcourse, darkened -in .dif:- ferent degrees.- For identificatiomwe havecalled the six triangles U; V, W, X, Yand Z. If we .as-, sume that triangle U receives the shortest ex-; posure, its, A corner will ,showrelatlyely little density. The A corner of the V triangle will show somewhat more density and the blackened area will extend further into the interior of the triangular area. The last triangle Z will be almost entirely black. On the second sheet we have the same appearance except that the B corners are at first slightly, and then more and more blackened, see Fig. 9b, and the same is shown on the third sheet, see Fig. 5, with respect to the C corners. It is diflicult to portray the appearance of these test sheets in the drawings, but the foregoing description should explain the situation adequately. The three sheets are then subjected to whatever treatment is necessary for the particular type of color print material selected. This includes a dye treatment with dyes of different colors for the threesheets, respectively. The three part images dyed in three different colors are then superimposed upon each other on a common base, and the temporary bases on which the exposures and the preliminary treatment took place are removed. A fairly large number of processes accomplishing this end have been developed, and it is not necessary at this point to go into details since these details do not form] part of this invention. After the three colored part images have been superimposed upon each other on a common base, the test print has the appearance as schematically shown in Fig. 901. It will be notedthat here the relative positions of the A and B corners are inverted as compared to the previous figures. This is due to the transfer of the image from one base to the other. In the final print, all A corners, for example, may be red, all B corners blue and all C corners green. The center of the triangle should be a more or less neutral gray. Due to the varying density in the A, B and C corners of the Various triangles, respectively, the over-all density and the brilliancy of the colors will vary for various triangles. This has already been explained above. The behavior of the color material on test prints of this kind permits various conclusions as to color balance and general sensitivity, and by means of these conclusions the making. of correct color vprints is being materially facilitated.

While we have described a preferred method of making test prints on color print material, it is obvious that the same is susceptible to changes without departing from the principles or sacrificing any of the advantages of the invention, as defined in th appended claim.

What we claim as new, is:

The method of making test prints of photographic color printmaterial of the separationtransfer type, comprising the steps of first, subjecting, on a first sheet of said material, a plurality of triangular areas to non-uniform exposures of varying lengths, said triangular areas aeeeme 1 1 having A; B and -C-corners,- all A corners receivingfull exposures; the sides opposite the all comers receiving no exposures, and inter-- mediate points receiving intermediate exposures independence upon their distance from said side, the length of the full exposure received by each "A" corner being difieren t for differenttriangles; second; treating a second sheet in like manner with respect to the B corners of said triangular areas, third, treating a third sheet in like manner with respectto the 0 corners of said triangular areas, corresponding triangular areas occupying identical positions on all three sheets, the respective A, B and C corners of each corresponding triangular area occupyingidentioal 12 positions ;on all three sheets, and the exposures received' by the A corner of-any triangular-area on "the first sheet being the same as the exposures received by the B and C' corners of the corresponding triangular areas on the second-and third. sheets, respectively, said exposures, *however, being-different fordifferen't triangles, fourth processing said three sheets in the usual manner, including developing, fifth, treating each of' th'e three sheets with a dye of a different color, and sixth, transferring the threecolored- -images, inregister with, and superimposed upon each Other; upon a common base;

ALFRED SIMMON.

LOUISL. WEISGLASS.

Images