CA1119867A - Projection printing apparatus and method - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An apparatus and method of making a parallax stereogram, i.e., free vision stereogram, and particu-larly for the accurate registration of a plurality of film images in order to ensure stereographic reproduc-tion. Each film frame having the image thereon in-cludes marks which are used in a projection printing apparatus to register the image in a desired position.
The registration is accomplished by mechanical align-ment according to the mark or by optically sensing the mark. A comparator-servo can adjust the film frame to the desired position. After registration each film frame is exposed onto a photosensitive material using a movable line grid. A lenticular screen is superimposed over the developed picture to form the stereoscopic photograph.

Description

à --1--~ACKGROUND OF THE INVENTION
Thi8 invention is directed to an apparatus and method for mnking A par~llax stereogram, l.e., free vision stereogram, and particul~rly for the accurate registration of a plurality of film lmages in order to ensure stereographlc reproduction. The inventlon is also directed to a proJectlon printing apparatus and method for making a stereogram and enlargements of fllm images to be used in such stereograms.
A photographic stereogram may be prepared by several methods: (1) a photograph taken with a con-ventional camera having a single obJecti~e and moving it or the obJect to successive viewpoints; or (2) a photograph taken wlth a camera havlng a Rlngle ob~ec-tive and an optical stereo attachment which enables two photographs of an obJect to be taken slmultaneously from two viewpoints; or (3) a photograph of an ob~ect with a ca~era having t~o obJectives whose separatlon is equal to the normal 6tereoscopic base of approxi-mately 65 mm. A combination of any of the foregolng methods may also be used. Each of the photographs is photographically broken up lnto a series of narrow strlps repre~enting alternatively the picture o~ the le~t and right stereogram.
In each of the above techniques the stereo-scopic e~fect is dlrectly related to the accuracy of æuperimposition of a plurality of lmages or the optical integration of a plurality of portlons of an image. It is therefore seen that the registration of the lmages for purpose~ Or viewing or printing is of considerable .

111986~

importance.
Furthermore in each of the above methods the ~ingle or multiple camera obJectives are directed to an aim polnt. The aim polnt is the point of convergence of the lenses in a multi-obJective lens camera or the center of arc of a ~ingle lens camera which rotates around the subJect or the center or rotation of the subJect which rotates durlng the camera expo~ure. The aim point 18 a vertical line within the image that will be at the rear surface of a viewing screen when the finlshed picture iB ~iewed. m e aim point i~ there-fore established and fixed before or when the photo-sensitive material is expo6ed. After expoaure the aim point cannot be changed or adJu~ted.
In addition it is often deslrable to provide an enlargement Or the film lmage prior to printing. In a conventional photographlc apparstus and method the de-termination of the enlargement occurs simultaneou~1y wlth the e~tablishment of the aim point. ~ the pre-sently known techniques for making a stereogram the degree of enlargement must be to an exact size to cor-re~pond with the pitch of the len~ elements of the viewing screen.

SUMMURY OF THE INVENTION
It is an obJect of the pre~ent invention to pro-vlde an apparatus and method for the pro~ection prlnt-ing of a plurality of illm images to make a stereogram.
It i8 an obJect of the present inventlon to pro-vide an apparatus and method for changing the aim point durlng proJectlon printing.

~ 7 1~

It 18 a further ob~ect Or the present lnventlon to provide an apparatu~ and method for the proJection printing of a marked film strip in order to produce a stereoscopic photograph.
It is a still further obJect of the preseht in-vention to pro~ide an apparatus and method for the ac-curate reglstration of a plurallty of film images prior to the proJection of a stereogrsm.
It is another obJect o~ the pre~ent invention to provide an apparatu~ and method for the enl~rgement of a film image without requiring such enlargement to correspond to the pitch of the lenticular element~ of a viewing screen.
In accordance wlth the invention the method com-prises the steps of providing a plurality of marked fi}m frames having image~ of the same sub~ect; registering a first film ima~e according to the mark on the fir3t fllm frame; optically proJecting the registered ~irst film image onto a line grld having alternating opaqus and transparent portion~ superimposed over photo~ensitive prlnting paper; registering a second ~ilm image sccord-ing to the ~ark on the second film ~r~me; optically pro-Jecting the regi~tered second film lmage onto the paper after cauæing sn lncremental relative movement between the line grid and the paper; sequentially registering each subsequent film frame and optica~ly pro~ecting each image onto th~ paper for each incremental rela-tlve movement between the line grld and the paper; and superimposing a viewlng screen over the subsequently developed paper. me plurality of film images may be 1119~;7 in a continuous strip form. Each film frame may be registered mechanically or by optical sensing. The marks may be caused by the removal of a portion from each film frame or by causing an optical density differential. If the marks are apertures in the film frame, registration is provided by pins extending through the apertures. Alternatively by optical sensing the mark a signal can be produced by each mark. The signals are compared and the film frame position is adjusted until the signals are substantially equal. The optical sensing can he by scanning the mark or by projecting an optical source and determining the source in relation to the mark.
In the apsects of the invention forming the subject matter of this divisional application there is provided a projection printing apparatus for making a stereogram comprising:
means for supporting a plurality of film frame images of the same subject, each film frame having a mark thereon to identify a corresponding homologous point in each film frame image to establish an aim point; means for registering the film frame image in a desired position according to the mark;
a line grid means disposed between the film frame image and photosensitive paper, the line grid having a repeatin~
pattern of alternating opaque and transparent portions, the transparent portions being of a given width; means for optically projecting the film frame image through the line yrid means onto the photosensitive paper so as to place the aim point at a given location on the paper and expose on the paper a portion of the film frame image equal to the given width of the transparent portions; and means for causing a linear incremental relative movement between the line grid means and the paper.

l~lg~67 BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims which particularly point out and distinctly claim the subject matter regarded as the invention herein, it is believed that the invention will be better understood from the following description thereof taken in conjunction with the accompanying drawings, in which:
Figure 1 is a schematic of an optical means for generating the frame registration marks;
Figures 2, 3 and 4 are partial schematics of a film frame showing several embodiments of the registration marks;
Figure 5 is a partial schematic of the projection printing apparatus comprising the enlarger and line grid for the printing of the film image;
Figure 6 is a partial schematic of the assembled stereoscopic photograph showing the lenticular viewing _ 4(a) -screen;
Figure 7 is a partial cross-sectional view of a mechan-ical means for registering the film frame;
Figure 8 is a partial schematic of an optical sensing means for registering the film frame;
Figure 9, appearing on the same sheet as Figure 1, is a block diagram showing the servo system for adjusting the film frame position; and Figure 10 is a partial schematic of the relationship between the servo system and the film frame.
DETA~LED DESCRIPTION OF THE INVENTION
Canadian Patent Application Serial No. 308956, filed concurrently with and assigned to ~he same assignee as the present application, discloses an apparatus and method for producing a parallax stereogram. The apparatus comprises a stable means for supporting a carriage assembly means, the carriage assembly means being movable on the stable means and supporting the film image frames. Optical means on the stable means permits the optical viewing of at least two image frames.
A mark is placed on each cf the plurality of frames as the carriage assembly is moved. The optical viewing establishes homologous points for each film frame image or is used to establish a stereo base distance to determine the homologous points. As used herein "homologous points" is defined as the two point images in a stereo pair which correspond exactly.
The carriage assembly means is moved by a programmed mechani-cal stepping or electromechanical means so as to allow a plurality of marks to be placed on each film frame sequentially.
The marks, to be used to register each film image, are ~lg~7 c~llsed by the removal of a portlon from each fllm frame or by causing an optical density dlfferential. The mark ca~ be effected mechanically, as by a punch, or optlcally, as by a focused laser. The laser or other narrow beam of radiation, removes or adds density to a portion of the emulsion layer for each film frame. The markings on each film frame can be arranged in a different size, orientation or shape relative to the image`on the frame or to each other. The marks permit the recognition of the correct or desired position or registratlon for each film frame by a mechanlcal or optical sensing means dur-ing the printing of each image. A pro;ecting printing apparatus comprising an enlarger and a line grid uses the marked fllm frame to expose photosensltive paper and prlnt the film image. A vlewing means, such as a lenticular screen, is affixed to the print to form the stereogram. Canadian Patent Application Serial No. 308955, filed concurrentl~ here~ith and commonly assigned with the present application, there ls dlsclosed a multl-ob~ec-tlve camera for provlding the plurality of film frameimages preferably in a continuous film strip.
Referring to Figure 1 the optical beam of a laser 79 preferably having a wavelength of 0.7 to 0.3 mlcrons, is reflected from a mirror 80 to a beam splitter 81.
Beam splitter 81 dlvldes the optical beam into two beams which are directed onto the fllm 83 through lenses 82.
One of the two dlvlded beams is directed onto the film 83 by a mlrror 84. The laser removes a selected por-tlon of the emulslon layel from the fllm frame or adds to the optlcal densl~y of a portlon of the emulslon layer or may cause a removal of the film and provlde an aperture. The marklngs on the film 83 whether optically or mechanlcally formed are representatively shown in Figure 2 to 4. The markings may be arranged in a different orientation, size, shape or location relative to the image on the frame or to each other.
The orientation, size, shape or locatlon differentia-tion permits the recognltion of the correct registra-tion for each film frame 91 by a mechanical means or optical sensor during the printing step of each image.
In Figure l there ls disclosed dividing the optical beam into two beams. It is understood that the number of optical beams can be varied as necessary to ensure proper reglstration. In a similar manner the number of mechanical punches may vary. In Figure 2 to 4 the marks are shown as belng circular and rectangular. The shape of the mark is not critical and other shapes are possible. By way of example the laser optical beam or the mechanical punch may be shaped to provide any regu-lar or irregular polygonal configuration. In Figure 2two of the three marks 90 are of the same shape but are in diagonally opposite locations with respect to the film image 91. In Figure 3 two similarly shaped marks 85 are shown, each mark located ad~acent op-posing sides of the film image and ad~acent a sidecommon to the opposing sides. In Figure 4 the three marks 86 are each of the same shape but are in a dif-ferent orientation relative to the film image 91. It is understood that the location of the marks relatlve to each other or to the film image or the location of 1119~;7 the marks on the fllm lmage le not critical. In Figure 3, for ex~mple, the narro~ well-defined l~ser optical beam has caused a change in the optlcal den3ity of the ~ilm 83 ad~acent to the fllm lm~ge 91 and pro-duced marks 85. In Flgures 2 and 4, for example, the laser optlcal beam hae provlded ln the film 83 ad~acent to the film image 91 a plurallty o~ apertured ~ark~ 90 and 86, respectively.
Figure 5 schematlcally sho~s the overall pro-~eeting printing apparatus. EYlarger 13 includes an optical source 92 whlch proJects through lens 93 a selected image fræme ~rom the film 83. The film 83 i~ stored in a cas~ette 94 whlch has been removed from the camera and processed, Located between the film 83 and the lens 93 18 registratlon means 89 which posltions the selected rilm ~mage prior to pro~ection and prlnting.
m e film image 91 iB pro~ected towards a line grld 14.
The line grld 14 comprises a movable llne grld g7 which 18 divided into a plurality of o~aque 98 and tran~-parent 99 sectlons extending across the width of the grid ~n a repeatlng pattern, The basic repeating patte m has a wldth equal to the wldth of the base 100 o~ each -lens 101 on the le~tlcul~r screen 96, as shown ln Flgure 6, The wldth of the transparent portlon 99 of each basic repeatlng pattern is deter~ined by dlviding the total wldth of the repeating pattern by the number of image frame~ to be pro~ected 3nd printed. Stated ln another manner the wldth Or the transparent portlon 99 of each basic repeating pattern i6 equal to the number of camera len~es, i.e., the number of simultaneously 1~19867 taken film frames, dlvided into the total width.For ex-ample, if there are seven lenses and 4he total width of the basic repeating pattern is 0.021 inches, then the wldth of the transparent portion 99 ls 0.003 inches and the opaque portion is 0.018 lnches. The total number of the basic repeating pattern is equal to the total number Or parallel lenses 101 on the lentlcular viewing screen 96 of the final product. The line grid 97 is located between the enlarger 13 and the print paper 95.
In processing, each frame ls printed onto the paper 95 and slmultaneously across the entire grid 97 for the wldth of each of the transparent portions 99 of the repeatlng pattern. When the film 83 is a contlnuous Btrip, the film is advanced by one frame and the gria ~7 is moved in the same direction in 0.003 inch increlllents so to print simultaneously acro~s the paper 95 each successive frame. Each of the lmage frames 91, for example, seven, is printed sequentially but for each lens 101 of the lentlcular viewing screen 96. At the completion of the processing ln the llne grid 97 the paper 95 has a plurality of prints across the paper equal in number to the number of the lenses 101 on the lenticular viewing screen 96, the wldth of each print being equal to the base 100 of each lens of the vlewlng screen and each print comprising each of the film lmages 91.
The prlnt paper 95 is then processed to produce the photographed subJect. The lentlcular viewing screen 96 ls placed over the plcture so as to align each lens base 100 with a respec~lve one of the now-developed re-peatlng pattern, and laminated lnto a flxed posltion.

8~;7 As used herein "paper" refers to the use of any photosensltlve materlal either positive or negatlve. Any commerclally available photosensltive film can be used to provlde the plurallty of images. Preferably the fllm should be dlmensionally stable and an Estar based film ls especially desirable lf the markin~ is accompllshed mechanically. Preferably the film images are formed on a continuous film strip. The method of the present in-vention can also be practiced using a plurality of separate film lmages provided from a plurality of cameras or from a plurallty of camera positions.
The optical and physiological principles associated with vlewing the assembled parallax stereogram, as shown in Figure 6, are well-known. The viewlng of a parallax stereogram ls descrlbed in U. S. Patents 3,482,913 and 3,504,059 and 3,508,920, in the name of W. E. Glenn, Jr.;
and in U. S. Patent 3,678,833 in the name of S. L. Leach.
A sultable technique for registering and lamlnating the lenticular screen 96 and the print 95 ls disclosed in U. S. Patent 3,462,226 in the name of J. E. Huffaker.

Figures 7 to 9 disclose several embodlments bf means 89 for registering a selected film image of the film frame in the pro~ecting printing apparatus. In Figure 7 a mechanical registration means 40 is shown comprlsing cam actuated pins which extend through the registration aperture marks 86 or 90 on the film 83.
Figure 7, a schematic cross-sectlonal view, shows the fllm 83 dl~posed on a transparent member 41. The *Trademark -11~

transparent member 41 ls mounted in a support 59 of an lrltermediate frame portion 47. Located over the fllm 83 ls the reglstration means 40 comprlslng cams 42 and pins 53. As shown in Figure 7 the rotatlon of cams ralse and lower a pin plate 44. The pin 43 is secured to the pln plate 44 by nut means 45. The pin 43 extends through an opening 46 ln lntermedlate frame portlon 47, the aperture 86 or 90 and an openlng 48 in support 59. The intermediate frame portion 47 has openlngs 57, 58 to permlt the pro~ec-tion of the fllm lmage. In Figure 7 the pln plate is shown in the raised posltion so as to dlsengage the pin from the film frame. Only one pin ls shown lt being understood that there may be more than one pin and the number of pins may be equal to the number of aperture reglstratlon marks on the film frame. As noted earlier, the cross-sectlonal shape of the pins may be complimentary to the shape of the aperture marks. As noted earlier, the number, shape, location orientation and size of the aperture marks may be formed by a suitably shaped and directed mechanical punch or optical beam. A gulde pin 49 extends through an opening 50 ln the pin plate 44, an opening 51 in intermediate frame 47 and an openlng 52 in the support 59. The guide pin 49 is supported between an upper frame portion 53 of the registratlon means 40 and a lower frame portlon 54 by sprlngs 55 and a nut 56 threaded onto one end of the pln. It is understood that there may be more than one guide pin.
The lower frame portion 54 has an opening 60 and the upper frame portion 53 has openlngs 61, 62 to permlt the pro~ection of the film image. During the ralsing ~9~67 and lowering of the pin the guide pin pro~ides means for preventing the misalignment Or the pin with the registration aperture and reduces the possibillty of damaging the film. In operation a first fllm frame is disposed on the transparent member and the cams are rotated allowing the pln to be lowered and extend through the reglstration aperture. After extending through the aperture the film frame posltion may be maintained by a clamp means. The optical source 92 causes the film image to be pro~ected through lens 93 onto the line grid 14.
The film image ls pro~ected through transparent portions 99 of the line grld 97 onto photosensitive paper 95. A
second film frame ls then disposed on the transparent member and registered wlth the pins extending through the aperture. An incremental relatlve movement between the line grid 97 and paper 95 ls provided preferably by the movement of the line grid 97. The magnitude of the in-cremental relative movement is equal to the width of the transparent portlon 99. As noted earlier, the width of the transparent portion 99 is determined by the total width of the repeating pattern and the number of film images to be pro~ected. The optlcal source 92 causes the second film image to be pro~ected through the lens 93 onto the llne grld 14. The second fllm lmage is pro-~ected through transparent portions 99 of line grid 97 onto photosensitive paper 95. Third and subsequent film frames are dlsposed on the transparent ~upport and regis-tered. An incremental relative movement between the line grid and the paper is provided and each film image ls pro~ected onto the paper. The number of film lmages is determined by the number of effective ob~ective lenses on the camera or the number of film lmages of the same sub~ect which are to be used to form the stereogram.
Where the plurallty of fllm lmages are ln the form of a contlnuous fllm strip, such as ln a cassette 94, the in-cremental relative movement should be in the same di-rection to that of the advance of the film strip through the pro~ection printing apparatus. A continuous fllm strip is shown in Flgure 10 extending between fllm spindles 71. Film motor means 72 permits the advance or reverse of the fllm strip relatlve to the registratlon support.
Figure 8 schematically shows an optlcal reglstra-tion means 74. A plurallty of solld state optical sources 75, such as light emittlng dlodes, each pro~ect a beam of radiation onto the film frame 91. The beam ls pro-~ected onto the fllm frame 91 ln the vlcinity of the registratlon marks. After passlng through the fllm frame 91 the beam is reflected by mirror 76 onto a lens 77 which pro~ects the beam to a multi-element optical sensor 78. The lntenslty of the beam received at sensor 78 is determlned by the relative posltion between the reglstratlon marks and the radlatlon from the optlcal source. As noted earller, the regiætratlon mark can be an aperture in fllm whlch wlll not attenuate the lntenslty of the beam as compared to the fllm ltself. Alternatlvely the reglstratlon mark can reduce the lntensity of the beam relatlve to the film ltself where the mark has a greater optical density. The desired position of the image frame can be achieved by ad~usting the relative position of the image to the beam so as to cause the output of each sensor ~9867 to be substantially equal. The fllm frame can be part of a continuous strip and can use the apparatus of Figure lO. In operation the optlcal registration means of Figure 8 is the same as that of the mechanical regis-tration means of Flgure 7.
In another embodiment of the optical registration means the film frame can be scanned to determine the location of the registration marks. A well-defined focused scanning radiation source is pro~ected onto the moving film strlp in the vicinity of the registration marks. The radiation source can be sinusoidally scanned at 500 Hz. Referring for example to Figure 4, an optical sensor for registration mark "A" will sense the mark A
for a longer period of time than the optical sensors for marks B ana C. For example, consider the marks 'IA", "B" and "C" as a rectangular shape having a length of 0.100 inches and a width of 0.010 inches. In the film advance or rewind direction (X-direction), at a film speed of one inch/second, the A sensor can "see" the A registration mark for 0.1 seconds. At the 500 Hz scanning rate the signal to the A sensor would persist for lO0 successive scan half-cycles. The orientation in the X-direction of the B and C registration marks relative to the film image~ however, causes the signal from the sensors for each of these marks to persist for a considerably lesser amount of time, e.g., lO successive scan half-cycles. Thus, sensor logic can determine the simultaneous occurrence of (a) 30 successive A sensor signals at the approprlate intersignal period of 0.001 seconds and (b) 500 Hz slgnals present from the B and -14_ 11198~7 C sensors. When this condltlon ls detected the motor causing the fllm travel can be braked and stopped. The stationary film lmage can be flxed ln posltlon on a film support table 73 by a clamping means. Sensor loglc, as in Flgure 9, can then actuate a servo flne motlon system for the table and positlon the film lmage.
The servo system has sensors 67 for each of the marks, such as marks "A", "B" and "C", which can responsively posltion the table ln the X, Y and ~ dlrectlons until the sensor signals are substantially equal. The X-directlon ls the wind or rewlnd directlon; the Y-direction is transverse to the X-direction; and the 0 directlon is the angular rotation of the fllm lmage. The output of each sensor 67 ls the input to a comparator 68. The output of the comparator 68 actuates respective X, Y
and ~ dlrectlon servos 69 whlch positions the film lmage 91, for example, on support 73. When the signals are substantlally equal the fllm image can be pro~ected onto the line grld 14.
The sensor loglc of Figure 9 can also be used with the optlcal senslng embodlment descrlbed in Flgure 8. In addltlon, lnstead of the radlatlon source the optical sensor can do the scanning.
In the reglstratlon means descrlbed herein the tolerance for overall alignment of any film lmage should not exceed a clrcle of one mll diameter. Stated ln another manner any representative small common feature of each of the film lmages for a particular stereogram should be brought, in the proJection printing apparatus, to wlthln 0.5 mll of an "average" point. The solld state optlcal source of Figure 8 on the scanning radiation source is preferably in the blue wavelength to take advantage of the greater o~tical densit~
of the fllm at that wavelength. The film may be an Eastman Kodak, 70mm, Varlcolor II, 2107 Type S, photo-graphic film or any equivalent thereof. The fllm may be of any size or type so as to be compatlble wlth the apparatus or user requlrements or vice versa.
~`anadian Patent Applications Serial No. 308956 and .Serlal No. 308955 there is dlsclosed an apparatus and method ror establishing the alm polnt a~ter the photographlc film has been exposed wlth a glven sub~ect.
Appllcation Serial No. 308956 dlscloses an apparatus ror establishing the plurality of corresponding alm points ~or the plurality of rilm lmages or the stereo base distance establlshed by those polnts. During the projection printlng according to thls appllcation an operator or person viewing the print may decide that the picture would be more pleasing or aesthetically improved i~ the alm polnt~was moved forward or backward from that whlch was previously established. The alm polnt can be ad~usted by movlng the enlarger lens 93 in small predetermlned horizontal increments to displace the pro~ected film image more or less than the stereo base distance. Alternatively the aim polnt can be ad-~usted by the lncremental horlzontal movement of the line grid 14, l.e., the llne grld 97 and paper 95 move together. In elther technlque only the pro~ected fllm lmage ls dlsplaced as the fllm frame remains flxed on the reglstratlon means. Dlsplacement of the pro~ected *Trademark image so as to change the aim point, viz., stereo base clistance, pe~mlts any degree of enlargement of the entire film image. Similarly such a dlsplacement of t;he pro~ected film image permlts the enlargement and/or stereographic reproductlon of any corresponding portions of the fllm images. The enlargement according to this invention does not have to be to an exact size to match the screen pltch of the lenticular screen 96.
Furthermore, as disclosed above the incremental movement between the film direction and the line grid is such that the grid is moved in the same direction as the fllm while the paper is stationary. Alternatively the grid may be stationary and the incremental relatlve movement provlded by moving the paper ln the dlrection opposlte to that of the film~
Varlous modlflcations and improvements may be made by one skilled in the art to the method and ap-paratus disclosed herein without departing from the scope of the invention as defined by the claims.

Claims (17)

What is claimed is:

1. A projection printing apparatus for making a stereo-gram comprising means for supporting a plurality of film frame images of the same subject, each film frame having a mark thereon to identify a corresponding homologous point in each film frame image to establish an aim point;
means for registering the film frame image in a desired position according to the mark;
a line grid means disposed between the film frame image and photosensitive paper, the line grid having a repeating pattern of alternating opaque and transparent portions, the transparent portions being of a given width;
means for optically projecting the film frame image through the line grid means onto the photosensitive paper so as to place the aim point at a given location on the paper and expose on the paper a portion of the film frame image equal to the given width of the transparent portions; and means for causing a linear incremental relative movement between the line grid means and the paper.

2. An apparatus according to claim 1 wherein the registration means comprises mechanical means which engage the film frame mark.

3. An apparatus according to claim 2 wherein the mark com-prises an aperture in the film frame and the mechanical means com-prise a pin which extends through the aperture.

4. An apparatus according to claim 1 wherein the registration means comprises means for sensing the film frame to determine the mark on the film frame and produce a signal for each mark; and means for determining when the signals are substantially equal.

5. An apparatus according to claim 4 wherein the sensing means comprises optical sensors.

6. An apparatus according to claim 4 wherein the registration means includes means responsive to the signals to adjust the film image to the desired position.

7. An apparatus according to claim 4 wherein the sensing means comprises for each mark a solid state optical source and a multi-element optical sensor.

8. An apparatus according to claim 1 wherein the incremental movement means causes the line grid to move relative to the paper.

9. An apparatus according to claim 1 comprising a plurality of film frames forming a continuous film strip and wherein the incremental movement is in the same direction as the movement of the strip during registration of each film image.

10. An apparatus according to claim 1 wherein the film frame has a plurality of marks.

11. An apparatus according to claim 10 wherein each of the marks has a different relative orientation to the film image.

12. An apparatus according to claim 1 wherein the line grid transparent portion has a width determined by dividing the total width of the repeating pattern by the film frame plurality.

13. An apparatus according to claim l wherein the registra-tion means comprises means for sensing the film frame to determine the mark on the film frame and produce a signal for each mark, wherein the sensing means comprise an optical source scanning each mark and optically sensitive output means for each mark.

14. An apparatus according to claim 1 wherein the registra-tion means comprises means for sensing the film frame to determine the mark on the film frame and produce a signal for each mark, wherein the sensing means comprise an optical source for each mark and an optically sensitive output means scanning each mark.

15. An apparatus according to claim 1 wherein the plurality of film imags is a continuous strip and wherein the incremental relative movement of the paper is in a direction opposite to the movement of the strip.

16. An apparatus according to claim 1 wherein the optical projection means is movable in horizontal increments.

17. An apparatus according to claim 1 wherein the line grid and paper are movable together in horizontal increments.