US2607268A - Method for photographically varying one dimension of an object with respect to another - Google Patents

Description

Aug. 19, 1952 F. H. BARTZ METHOD FOR PHOTOGRAPHICALLY VARYING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER Filed July 25, 1947 6 Sheets-Sheet 1 i @i b;

mmvrm Frederzck l1. Bartz M,$M aziomeys Aug. 19, 1952 F. H. BARTZ 2,607,268

METHOD FOR PHOTOGRAPHICALLY VARYING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER Filed July 2:5, 1947 6 Sheets-Sheet 2 '7 C INVENTOR.

Frederick l7. Bariz J 6 5 ditor eys lllili 19, 19.52 F. H. BARTZ 2,607,268

METHOD FOR PHOTOGRAPHICALLY VARYING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER Filed July 25, 1947 6 Sheets-Sheet 3 INVENTOR. fi'edzv'lck h. Bartz aiiorrzagzs A g- 19, 1952 F. H. BARTZ METHOD FOR PHOTOGRAPHICALLY VARYING oNE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER 6 Sheets-Sheet 4 Filed July 25, 1947 INVENTOR.

Frederick H. Bariz M BY 614 216 62 Z Zorrzeys Aug. 19, 1952 F H BARTZ 2,607,268

METHOD FOR PHOTOGRAEHIEALLY VARYING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER 6 Sheets-Sheet 5 Filed July 23, 1947 IN V EN TOR.

BY Frederick H.5ariz X/MQM (sa /16 (I i iorlze ys Aug. 19, 1952 BARTZ 2,607,268

METHOD FOR PHOTOGRAPHICALLY VARYING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER Filed July 25. 1947 6 Sheets-Sheet 6 INVENTOR.

Frederick li Bqnfz Patented Aug. 19, 1952 UNITED STATES PATENT'OFFICE g aemy'zce I A ING ONE DIMENSION OF AN OBJECT WITH RESPECT TO ANOTHER 4 Claims. 1

This invention relates to a method for photographically enlarging or reducing one dimension of a two-dimensional object with respect to the other.

An object of this invention is the provision of a method for photographically reducing the width of a drawing, sheet of printed material, or the like, in any predetermined amount up to 50% or even more without changing the length or height; and similarly, for reducing the length or height without changing the width.

- Another object of this invention is the provision of a method for photographically increasing the widthof a drawing, sheet of printed material, or the like, without changing the length; and similarly, for increasing the length without changing the width.

Another object is the provision of a method for photographically reducing both the width and length of an object in selected, diiierent amounts.

A further object is the provision of a method for photogra-phically enlarging both the width and length of an object in selected, difierent amounts. v

A still further object is the provision of a method for photographically reproducing an object whereby one dimension may be enlarged by a selected amount and another dimension may be reduced by a selected amount.

One practical application, whereby invention may be applied with considerable advantage both as to convenience in use and in economy, is in photographically varying the width, or height, or' both, of advertising copy so that it will fit the difierent space requirements for different magazines and newspapers without manually setting up a separate out for each required variation in copy size.

For example a two-column out set up originally for a newspaper, and having a width of centimeters,'would not fit properly in a magazine where the standard width of a two-column space is, say, 11 /2 centimeters. Since it is rare in suchthe cut for every magazine or newspaper using a different column width and it can readily be seen that these duplications of costs may amount to a sizable item in a large-scale advertising program where a particular ad is inserted in a number of difierent publications, each using a column width difiering from the others.

The present invention may be readily applied to the above-mentioned example to produce a photographic reproduction of the newspaper ad with the width increased to 11 /2 centimeters and the height held constant. A new cut, for the magazine, can then be made from this reproduction in the usual way. Other cuts, in different column widths required by different publications maybe similarly produced photographically by my method eliminating all of the tedious duplications of hand-settin required by conventional methods. 7

Certain trick photographic arrangements, using cylindrical lenses, prisms and the like have been applied in a limited way to photographically reproducing objects with one dimension enlarged or reduced more than the other, but these arrangements have not had any measure of success and their use has been limited to extremely small work and enlargements or reductions of only a few per cent. I

Accordingly, it is another object of the present invention to provide a method, employing an ordinarys-pherical lens, for photographically reproducing even large objects, which may have dimensions up to several feet, with one dimension being varied even as much as or more with respect to the other.

Other objects and advantages will be apparent from the following description taken in connec tion with the drawings in which:

Figure 1 is a side view of one form of photographic apparatus with which the present invention may be carried out Fig. 2 is a top view of Fig. 1;

Fig. 3 is an enlarged perspective view of the tiltable copyholder shown in Figs. 1 and 2;

.Fig. 4 is a vertical sectional view of Fig. 3 taken through the axis c-c;

Fig. 5 is a fragmentary, enlarged View of Fig. 1, showing a side View of the camera lens;

Fig. 6 is a view of Fig. 5 as seen from the right;

Fig. '7 is a top view of Fig. 5, with a superposed, broken-line view of the lens in tilted positio with respect to the camera axis c-e;

Fig. 8 is a diagrammatic view of the object and negative image illustrating the negative-making step of the present invention;

Fig. 9 is a view similar to Fig. 8 illustrating the succeeding, positive-making, step;

Fig. 10 illustrates, in orthographic projection, the comparative sizes and shapes of a negative and positive made from an object in accordance with the method of the present invention;

Fig. 11 is a diagrammatic view of the apparatus showing an optimum relationship between the copyholder and lens angles relative to the camera axis;

Fig. 12 is a view showing an object containing printed material or the like as disposed on the copyholder for the negative-making step;

Fig. 13 is a view showing the negative disposed on the copyholder during the rephotographing or positive-making step;

Fig. 14 is a view of the positive image projected on the plate holder in the camera during the rephotographin step; and

Fig. 15 is a perspective view of a further embodiment of my apparatus.

One form and arrangement of apparatus for carrying out the objects of the present invention is shown in the drawing, and includes a camera 2| and a copyholder 22 supported on a pair of fixed rails 23.

The camera 2| has a bellows portion comprising spaced frame members 24, 25 and 26 with flexible, accordion-like members 21 and 21a therebetween. The front frame member 26 is substantially closed on its forward face and carries a plate 28 secured thereto by screws 28a (Fig. 6). This plate is formed with a central opening surrounded by a tubular, forwardly extending section 28b within which a lens mounting tube 29 is journaled for rotation about the camera axis cc by the selector knob 3|, the latter being operably engaged with said mounting tube by gear means (not shown). A lens 32 is pivotally mounted within the rotatable tube 29 On trunnion pins 33 and 33a which are pivotally journaled within the tube 29. A rod 34, an extension of trunnion 33, carries an arcuately movable pointer 36 and an operating knob 31 which may be employed to change the disposition of the lens axis bb with respect to the camera axis cc as shown in Fig. '7. An index plate 38, mounted on the forward end surface of the rotatable mounting tube 29 beneath the pointer 36, is marked in degrees, radians or other suitable units to indicate tilt of the lens with respect to the photographic axis cc.

The rear portion of the frame member 24 is adapted to alternatively retain a ground glass member and a photo-sensitive plate holder in the position indicated by the numeral 39; spring clips 4| are provided to maintain the ground glass or plate holder in place.

Means for moving the ground glass (or plate holder) back and forth with respect to the lens comprises a shaft 42 rotatably journaled in rearwardly extended portions 43 of the frame member 24. One end of the shaft 42 carries an operating Wheel 44 and the portion between the extensions 43 carry a pair of pinions 46 and 46a engaged respectively with a pair of racks 41 and 41a which are mounted on the supporting member 48.

The supporting member 48 is slidably carried by the truck 49 having rollers 5| and 5m engaged with the rails 23 for major movements of the whole camera assembly relative to the copyholder. Normally the truck 49 will be locked in position by a suitable rail-gripping means shown diagrammatically here and havin shown in Fig. 7.

an operating wheel '52. The rollers 5l-5la are peripherally grooved or beveled as shown to facilitate tracking on the rails 23. The rollers '51 are connected by a shaft 53 having an operating wheel 54 which may be turned to drive the assembly forward or backward for a major adjustment with respect to the copyholder. For minor adjustments, a crank 56 is provided for rotating a rod 51 having a threaded section (not shown) engageable with a threaded bushing (not shown) secured to the truck 49. Since the shaft 5'! is rotatably journaled on the bellows supporting member '49, it will thus be seen that rotation of the crank 56 will be effective to move the supporting member relative to the copyholder without changing the distance between the lens and ground glass.

Summarizing now the operation of the working parts of the camera assembly, turning the lens knob 3! is effective to rotate the lens mounting tube, and hence the lens itself, about the camera axis cc. Turning the lens knob 31 is effective to tilt the lens, within its mounting tube 29, with respect to the camera axis, as Turning the operating wheel 44 varies the distance between the lens 32 and ground glass (or plate holder) 39. And turning the crank 56 or the wheel 54, depending on whether a minor or major adjustment is required, is effective to move the entire bellows assembly toward or away from the copyholder.

The copyholder assembly, already generally designated 22, includes a copyholder or board 51' having horizontal and vertical ruled lines on the side facing the camera. The top of this ruled surface is covered by a glass 58 carried in frame 59 which is latched in place by hook members 6i secured to one side edgeof the board, the glass-supporting frame 59 having its opposedside edge hingedly supported on the peripheral frame 68 carried by the board. This construction facilitates the rapid insertion beneath the glass of an object to be photographed and the clearance between the glass and the board will preferably be small in order that a sheet of copy, negative or other object interposed therebetween will be pressed quite flat for the best photographic reproduction.

In the present instance, theboard 51 is mounted for pivotal movement about both horizontal and vertical axes by structure now to be described. A pair of horizontal pivot pins or trunnions 62 are mounted at the center of the side edges of the peripheral frame 60 and, for best results, the. axis of these trunnions should lie in the plane of the ruled surface of the board (see Fig. 4) so that pivotal movement of the board about the pins 62 will not displace the horizontal centerline 63 either upward or downward. The pins '62 are journaled at the upper end portions of the" arms of a U-member com prising a. base- 64 :and the upstanding arms 66 and 66a. The pivot pins 62 are threaded for engagement by locknuts 6! which function to maintain the copyholder at any adjusted arr-- gularity about the horizontal axis which in this case preferably coincides with the ruled hori zontal line 63 as above-stated. Means for de-- termining' this angularity include a stationary pointer 68 mounted on the upright 66 and a' protractbr 69 having an arcuate scale under the The base 64 of the U-member described in a previous paragraph has secured to its underside, as by welding, a pivot stud 12 (Fig. 4). This stud is vertically mounted in alignment with the center 65 of the board. That is, when the board is vertical, as shown in Fig. 4, the axis of stud 12 lies in the plane of the ruled surface coincident with the ruled centerline II. The stud '12 extends downwardly through the transverse angle members 13 and 15 (to be described), through the bushing 14, and terminates in a threaded portion having a wing nut 16 for locking the board where desired.

The copyholder is supported on a framework comprising the transverse disposed angle member 13 spaced above a similar but longer member 11 which is joined thereto as by welding to diagonally disposed members 18 and 18a. Spaced backward therefrom along the rails 23 is another transversely disposed angle member 8| connected to member '11 by longitudinal straps or bars 82 and 82a which are riveted or otherwise suitably secured to the respective members. The diagonal strut 15 connects the members 13 and 8! to impart rigidity to the entire supporting structure. A pair of semitubular shoes 83 are longitudinally secured, as by welding, across the bottom members H and 8| and engage the tubular rails 23. The copyholder assembly may be locked at a preferred position by means of a transverse bar 84 engaging the underside of the rails, this bar being held upwardly thereagainst by bolts 86 and locknuts 81 carried by the members 82.

To facilitate disposing the copyholder at a particular angle about the vertical axis, an arcuate index plate 88, suitably graduated in degrees or other units, is secured to the underside of the U base member 64 for movement therewith. Cooperating with this movable scale is a fixed pointer 89, carried by the stationary plate 9| which is secured atop the strut 15.

Since the horizontal and vertical pivotal axes of the copyholder, in the embodiment just decribed, are coextensive respectively with centerlines 63 and 1 I) when the copyholder is vertically disposed as in Fig. 4), the center point 65 of the copyholder will remain fixed with respect to the camera, irrespective of pivotal movement of the copyholder and this fixed point thereby provides a valuable and convenient point for measuring the distance from the copyholder to the camera.

A number of lights 92, 92a, 92b, and 920 will generally be advantageous with this equipment to properly illuminate the object on the copyholder.

The method used to photographically distort an object in accordance with this invention comprises a first step of photographing the object to produce a negative having perspective, and a second or rephotographing step in which the negative is photographed to simultaneously eliminate said perspective and to produce a positive of the desired configuration. For simplicity in description, the examples presented herein will relate to cases where the height of the object is reproduced on a larger or smaller scale than the width. It will be understood, however, that the width may be similarly varied with respect to the height; or, by diagonally disposing the object, and subsequently the negative, on the copyholder, as will be seen, any diagonal dimension may be varied with respect to another.

The geometrical principles involved in the present invention may be most easily understood by first considering a procedurein which the photographing and rephotographing are carried out by using focusing means consisting of a pinhole aperture instead of a lens and by assuming that camera projections concerned in this procedure are true central (conical) projections. By means of this assumption the explanation of the principles underlying the invention will be greatly simplified. After the general principles have been explained in this way, certain refinements of procedure for use with a lens instead of a pinhole will be explained, particularly the optimum relationship between the angle of tilt of the lens and that of the copyholder. Following the description of these geometrical principles, certain specific, practical examples of methods of applying them will be described.

Figs. 8 and 9 are diagrammatic isometric representations, respectively, of the first and second steps employed in the method of the present invention. In the first step, a rectangular object WXYZ, carried by the copyholder, centered at D on the camera axis cc and tilted an angle d1 relative to said axis, is projected, through a pinhole 0, as a vertical image W1X1Y1Zi on the negative plate holder. From that image, a negative WzXzYzZz is made and rephotographed, tilted at an angle d2, on the same equipment, with its optical center D2 on the axis cc, as shown in Fig. 9, to produce a positive image WsXsYaZa having a predetermined reduction of height with respect to width. Relative sizes and shapes of the object, negative and positive are shown in Fig. 10 where it can be seen that perspective is introduced into the negative and is then removed in rephotographing to make the positive.

In both steps shown in Figs. 8 and 9, a line (PQ in the object) is carried through to represent the vertical centerline and, as will be seen, is helpful in the derivation of formulas as well as facilitating a visual comparison between positions the object, negative, and positive.

During the first, or negative-making step, as shown in Fig. 8, dimensions and angles are indicated by the following symbols:

Z1=DO=distance between pinhole at O and the non-movable centerpoint D (placed over point 65 on the copyholder) M=D1O=distance between pinhole at O and the optical center D1 of the negative image d1=angle of tilt of object on copyholder relative to camera axis cc w=PW=PX=half width of object p=DP=DQ=half height of object During the second, rephotographing, or positive-making step, as shown in Fig. 9, dimensions and angles are indicated by the following symbols:

lz=DzO=distance between pinhole O and the non-movable centerpoint D (placed over point 65 on the copyholder) A2=D3O=distance between pinhole O- and optical center m of the positive image d2=angle of tilt of negative on copyholder relative to camera axis cc in addition, a general term R will be employed to denote the foreshortenment ratio, this being' defined as 3 BQPQ E1321 Solving for DsPs,

Solving for B2P2-2 d B P' D P cos d202 2=D P fffi Therefore,

k p cos d1 00's (22 Solving for B2D2:

sin d1 Now substituting: 3) and (4) in 2),

Solving for n+1; sin d Solving for A 13 Nowsubstituting (7) and (aim (6),

sin (12 l i-"psin d1 Nomsubstitiiting s), (9'), and (12) in (1'); the

1 sin d 1 A p cos d sin (1 Width at P 2 2 z t s 7 Mp cos, d' s'ind (12 5 tan d1 And, using com'montrigcnometric relationships; this-may be rewritten as (19) 05s d= 1 mea Now substituting 13 and (19a in (143-, we ob:-

12 0'05 03 eas d, V

9 tain a general formula for R in terms independent of d2: 7

l 2 cos d 1 tan d Mi -p Sill d p COS tan d1 2 cos d 1 tan d;

This simplifies to 3 (2o R=cos a 1 tand,

Procedure I .Reducing one dimension while holding the other constant Considering now a specific, practical example where the width of the object is to be reproduced in a one-to-one ratio and the height only is to be foreshortened, this may be carried out by adjusting the distances of the copyholder and ground glass from the pinhole so that Similarly for such case the relationship between di and (12 as expressed by Equation 18 simplifies to Sill d1 (22) sin dz=tan (11 Considering now a practical case, assume the object WXYZ is high and 10" wide and that it is to be photographically reproduced in accordance with the principles set forth above so that the positive WsXsYaZs is 8" high and 10" wide. The quantity R, therefore, will be .8, and substituting this value in Equation 21, it will be seen that the copyholder angle d1 for making the negative should be 25.1". Then, substituting this value of di in Equation 22, it will be seen that the copyholder angle d2, for making the positive, should be 27.9",

For much commercial work a pinhole will be too slow and a tiltable lens, such as that shown in the drawings, will be more advantageously employed. I have found, that when using a lens instead of a pinhole, the lens should be tilted onehalf the amount of, and in the same direction as the copyholder to properly focus the image on the vertical ground glass or photosensitive plate holder in position 39, as shown diagrammatically in Fig. 11. Where the plate holder is not disposed at right angles to the camera axis cc, the lens angle will, of course, have to be varied to compensate for such disposition. Using a plate holder at right angles to the camera axis, as shown, the lens angle should be half the copyholder angle in both the negativeand positive-making steps. In other words, in the first step, lens angle 51: /2 copyholder angle d1; and in the second step, 52: /2 copyholder angle d2. Thus, for the case considered in.the preceding paragraph, the optimum lens angle for making the negative will be (25.l) =l2.55 and for making the positive will be (2'I.9")=l3.95".

Using the relationships expressed by Equations 31 and 22,, and calculating the lens angle (where a lens instead of a pinhole is employed) as onehalf of the copyholder angle in each case, a table such as the following may be prepared, showing the optimum copyholder and lens angles:

,i Angles for Making Angles for Making deduction Negative Positive of Height H l C h 1d 0 h ld e onopy 0 er opy 0 er Smut) I Angle, Lens Angle, Angle, LensAngle,

R $1 I d2 52 Degree Degree Degree Degree .95 12.8 6.4 13.1 6.55 18.0 i 9.0 18. 9 9. 45' 85 21. 9 10. 23. 7 11. 85 .80 25.1 I2. 55 27. 9 13. 95" .75 27.9 13. 95 32.0 16.00 7O 30. 3 15.15 35. 8 17. 9 65 32. 6' 16.3 39. 8 19. 9 .60 34.5 17.25 43.4 21.7 55 36. 3 18.15 47. 2 23. 6 a 50 37. 8 l8. 9 50. 9 25. 45

It will be appreciated by those skilled in the photographic art that these optimum figures may be varied suitably in one direction or the other to compensate for practical variations from theoretically exact procedure, due, for example, to contractionor expansion of emulsion sheets during developing and drying. Stretch or shrinkage of emulsion paper can usually be controlled to a known amount by'using the same paper and developing technique in every case;

Location of the optical center of the negative is greatly facilitated by the use of aligning means such as the center lines 63 and H ruled on the copyholder. In the negative-making step the object WXYZ is disposed on the copyholder with the outer ends ofthe center lines 63 and H projecting beyond the edges of the object, as shown in Fig. 12. These projecting ends of the, center lines will be reproduced as lines 63a and Ha respectively on sheet 99 which carries the negative W2X2Y2Zz and, for the rephotographing step, this negative-carrying sheet is placed on the copyholder with its lines 63a and Ha in registration with the copyholder lines 63 and II respectively, as shown in Fig. 13. Thus, since the optical center of the negative is at the intersection of lines 63a and Ha, the use of this novel apparatus with this procedure will insure thatthe optical center is positioned at the center point 65 of the copyholder (that is, intersected by the photographic axis c-c), for the rephotographing step.

Fig. 14 shows a view of the image of the negative as projectedonto the photo-sensitive plate during the rephotographing step and illustrates how the resulting positive W3X3Y3Z3 can be projected as a completely rectified (that is, free from perspective) reproduction of the object WXYZ, with the height reduced relative to the width.

Procedure II.-Enlarging one dimension while holding the other constant Procedure will now be described for the case where the width of the object is to be reproduced in a one-to-one ratio but the height is to be increased. This may be accomplished by a first overall enlargement, in accordance with conventional photostatic enlargement practice, to produce a positive having the required height, followed by reducing the width only, to the required amount, by the method outlined in Procedure I," above.

Taking a specific example, assume a 10" x 10" object is to be reproduced with a height'of 12" and a width of 10''. The object is placed on. the copyholder 22 and the-lens (or pinhole)- axis b- -b isaligned with the copyholder axisalong the camera axis c-c; The copyholder and plate holder distances, Z and), are adjusted to project an image of 1 2" x 12" on the. emulsion sheet in the plate holder. This is developed and printed in the usual manner to. produce a 12 x 12 positive. Next, the above-described Procedure. I is followed to reduce the width from 12" to 10" while holding the height constant, where Substituting this value. of R in, Equation 21,

d1==23.1. Substituting this value of d, in Equation-22, d2=25.2. Then, the 12. x 12" positive is placed upright on the. copyholder and preferably'centered thereon with the copyholder turned aboutpins 62 into a vertical plane.

The copyholder is then turned one direction or the other about its vertical axis through pivot bolt '12 to. an angle. d1,of 23.1". (An alternate pro- .cedure at. this point would be; tdplace. the

12' x 12 positive on its si'deand tilt thecopyholder an, angle d1 about its. horizontal axis.) The lens is, tilted, in the same direction as the copyholder, an angle d2 of 11.55"; The distances of the copyholder and plate holder along the. axis o--c will beset for an'overall ne -to-one reproduction, The sensitized sheet is exposed and developed into a negative. which. is distorted in perspective-seas to have its sides parallel, spaced at a. width somewhat less than 12", one of the sides being longer than the other. The negative is then placed on the copyhol'derwith its optical center at the intersection of lines 63. and II and with itslongest side remote from the camera, as shown in Fig. 9. To make the. desired positive reproduction, the copyholder is tilted further to an angle of 2512 and the lens is also further tilted to half this, or 12.6". Rephotographing will then eliminate the perspective which was introduced into the negative, and provide a positive having a. height enlarged to 12" but retaining the original width of Procedure III .-Reducz'ng both dimensions in difierent amounts:

To photographically distort an object. so that both dimensions are. reduced, but one is reduced to a greater extent than the other, the object is first photostatically reduced overall, in accordance with conventional practice; then, as described Procedure I, one dimension is further reduced while holding the other dimension unchanged.

Taking av specific example, assume a 10 x 10" object is to be reduced to 8" x '7". The object is first reduced overall to. produce an intermediate positive having dimensions 8" x 8". Then, using Procedure I, the 8" x 8" positive is photographically distorted to 8 x '7'.

Procedure IVL-Enlarging both dimensions in difierent amounts To. photograph-ically distort an object so: that both dimensions are enlarged, but. one is enlarged tov a greater extent than the. other, the object is: first. photostatically enlarged overall, in accordancewith conventional practice; then, as described. in Procedure I, one dimension is. reduced while holding the other dimension unchanged.

Taking aspecific example, assume a 10" x 10."

object isto be changed to 11"" x 9".

object is to beenlarged to. 12"" x 11"; The/0b- J'ect is first enlarged overall, as describedunder Procedure II to. anintermediate positive having dimensions-or" 12 x12. Then, using fProcedure. 1,. one dimensionoi, thelZ x 1.2." intermediate is reduced to provide the desired 12" x 12" reproduction.

Procedure V.EnZa rging, one dimension and reducing the other To, photograph-wallyreproduce. an Obj t one dimension enlarged and the other reduced, the object is first photostatically enlarged overall, in accordance. with. conventi nal practice, to enlarge thev one dimension to. the required value; then, as described in Procedure I said other dimensionis reduced, to. its required value while retaining said onev dimension. at its enlarged value.

Taking a specific example, assume alO" x 10 The Object is first enlarged overall, using conventional photostaticpractice, to an intermediate positive having dimensions of 11" x' 11''. Then, using the method described under Procedure I," where the 11 x 11" intermediate is photostaticallydistorted to the desire 11 x 9 size.

Fig. 15 illustrates a further embodiment of my apparatus, showing schematically one arrangement whereby the copyhol der may be linked to the lens so that movement of the copyholder 57 to a particular angle d will automatically move the lens 32 to its optimum angle ,8 for focusing an image on the plate holder or ground glass at position 39. In the specific arrangement shown in Fig. 15, the lens is pivotally mounted on axially aligned rods I-IlI-Ifliw rotatably journaled in. uprights Hid-IBM which are carried on a movable platform Hit, the lens being, mounted on the rods IIll-IOId so the axis of the rods iii-- tersects the photographic axis ec, One end, or both if preferred, of the platform IE5 is mounted as by screws I on a slide member II)? which is reciprocable along the slideway formed in, channel member I09, the latter being suitably supported parallel to the photographic axis. At the end of the rod IIlI a gear 302 is mounted, rotation of which is effective to rotate or tilt the lens. Another rotatable rod I03 is similarly engaged to tilt copyholder 5.1 in response to rotation of a relatively smallergear I03 mounted on the end 0 rod I93.

A rotatable shaft H0 having an operating crank III carries a worm Illfixed thereon, said worm being in mesh with the smaller gear I 03. Suitable thrust bearing means (not shown) are provided to permit the shaft IIEI to rotate but not reciprocate in either direction.

A portion II 3 of shaft H0 is provided with a non-circular cross-section (in this case, square) and a worm I I4, splined thereto, is provided with an internal bore of like, non-circular cross-section so as to fit on the shaft portion I I3 and be reciprocable but not rotatable with respect thereto. Upstanding thrust plates IIS-IISa, apertured for rotation of the shaft III! therewithin, are carried by the. platform I05 on opposite ends of the worm. H4. The structure just described provides for the translation of the lens along the axis c-c, toward or away from the copyholder, while maintaining a preferred relationship between the tilt of the copyholder and lens.

the gear and Worm means described will be constructed so the lens will be tilted only half as much as the copyholder. Where the thread pitches of the two worms ll2-l H are identical, this means that the diameter of gear I02 will be selected as exactly twice the diameter of gear I03.

With the arrangement shown in Fig. 15, the operator need not concern himself with the lens angle, since this well be automatically adjusted when he turns the handle I H to tilt the copyholder to a desired angle. The photographic distortion method of the present invention may be carried out merely by turning the handle III to set the copyholder at a desired angle, making the negative, then turning the handle to set the copyholder at the corresponding angle for making the positive, and rephotographing.

While I have described in detail certain preferred procedures to be followed in practicing my invention which I have found to be convenient and practicable, and while I have illustrated and described in detail certain forms of apparatus which I have found well adapted to carrying out the required operations, I do not wish to be understood as limiting myself to the performance of the process by the exact steps or the following of the particular sequences of operations, or by the use of the particular apparatus as herein set forth, as I realize that changes both in pro cedure and in the apparatus are possible. I therefore intend to claim my invention broadly in whatever manner its principle may be made use of.

I claim:

1. A method 01' making a photographic reproduction of a two-dimensioned subject comprising: arranging said subject in alignment with the lens and plate holder of a camera along a photographic axis thereof which is perpendicular to said plate holder; further arranging said subject to define a preselected angle of tilt between an axis perpendicular thereto and said photographic axis; arranging said lens with its axis tilted relative to the photographic axis in the same direction as said subject in an amount sufficient for focusing an image of said subject on said plate holder; photographing to produce a negative; arranging the face of said negative opposite that corresponding to said subject in the negative-making step mentioned hereinabove; further arranging the negative at a predetermined angle of tilt dz calculated from the relationship sin dzztan (11 where d1 and dz are angles of tilt of said subject and negative, respectively, relative to the photographic axis; arranging said lens with its axis tilted relative to the photographic axis in the same direction as said negative an amount sufficient for focusing an image of said negative on said plate holder; and photographing to produce a positive.

2. A method of making a photographic re production of a two-dimensioned subject com.- prising: arranging said subject in alignment with the lens and plate holder of a camera along a photographic axis thereof which is perpendicular to said plate holder; further arranging said subject tilted about a first axis intersecting the photographic axis to define a preselected angle of tilt between an axis perpendicular thereto and said photographic axis; arranging said lens with 14 its axis tilted about a second axis, parallel to'the first, intersecting the photographic axis, in the same direction assaid subject, in an amount sufficient for focusing an image of saidsubject on said plate holder; photographing to produce a negative; arranging the face of said negative reversed about said photographic axis relative to said subject in the negative-making step mentioned hereinabove and at substantially the same distance from said lens; further arranging the negative tilted about the first, axis in the same direction as said subject during the negativemakingstep but at a predetermined angle of tilt dz calculated from the relationship sin dzztan d1 where d1 and dz are angles of tilt of said subject and negative, respectively, relative to the photographic axis; arranging said lens with its axis tilted about the second axis relative to the photographic axis in the same direction as said negative an amount sufiicient for focusing an image of said negative on said plate holder; and photographing to produce a positive.

3. A method of making a photographic reproduction of a two-dimensioned subject comprising: arranging said subject in alignment with the lens and plate holder of a camera along a photographic axis thereof which is perpendicular to said plate holder; further arranging said subject to define a preselected angle of tilt between an axis perpendicular thereto and said photographic axis; arranging said lens with its axis tilted relative to the photographic axis in the same direction as said subject in an amount suificient to define an angle between the lens and photographic axes substantially equal to half said preselected angle of tilt for focusing an image of said subject on said plate holder; photographing to produce a negative; arranging the face of said negative opposite that corresponding to said subject in the negative-making step mentioned hereinabove; further arranging the negative at a predetermined angle of tilt dz calculated from the relationship sin d2=tan (11 where (11 and (12 are angles of tilt of said subject and negative, respectively, relative to the photographic axis; arranging said lens with its axis tilted relative to the photographic axis in the same direction as said negative an amount sufficient to define an angle between the lens and photographic axes substantially equal to half said predetermined angle of tilt for focusing an image of said negative on said plate holder; and photographing to produce a positive.

4. A method of making a photographic reproduction of a two-dimensioned subject comprising: arranging said subject in alignment with the lens and plate holder of a camera along a photographic axis thereof which is perpendicular to said plate holder; further arranging said subject to define a preselected angle of tilt d1 between an axis perpendicular thereto and said photographic axis; arranging said lens with its axis tilted relative to the photographic axis in the same direction as said subject in an amount sufficient to define an angle di z between the lens and photographic axes for focusing an image of said subject on said plate holder; photographing to produce a negative; arranging the face of said negative reversed corresponding to that of said subject in the negative-making step mentioned hereinabove; further arranging the negative in the position of the subject at a predetermined angle of tilt d2 calculated from the relationship sin dz tan air where (11 and dz are 15 .16 angles of tilt defined between the Photographic v UNITED STATES PATENTS axis and an axis perpendicular to the subject and Number Name Date negative respectively; arranging said lens with 1365638 Hastings V Jan 13,1921 its axis tilted relativeto the photographic axis in 1410 127 Roussuhe Man 21 1922 the same direction as said negative an amount 5 l713498 Cooke May 14 1929 Liz 2 for focusing an image of said negative on Aldis 1931 said plate holder; and photographing to produce 1910425 Cahm May 1933 a positive. n

- FOREIGN PATENTS R R C BARTZ- 10 Number Country Date 14,798 r Great Britain of 1902 REFERENCES CITED 448,166 Germany Aug. 12, 1927 V The following references are of recordin the ,7 Great Britain O 2 1 2 at this Pa-tent: 15 OTHER REFERENCES Clerc: Photography: Theory and Practice," 1937, pages 470-472.

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