US1545590A - Process for removing shadows from stereoscopic pictures - Google Patents

Description

. Patented July 14, 1925.

UNITED' STATES 1,545,590 PATENT oFFlcE.

ALFRED J'. IACY, OF CHICAGO, ILLINOIS, ASSIGNOB TO IACY ART PROCESS COB- PORATION, `A CORPORATION OI' ILLINOIS.

PROCESS FOB BEIIOVING SHADOWS FBOI BTEBEOSCOPIC PICTURES.

Application med April 11, 1921.

To all whom tt may concern:

Be it known that I, ALFRED J. MACY,

a citizen of the United States, and a resident scopic Pictures; an

from each eye\of the observer.

of the city of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in a Process for Removin I do herebydeclare that the following is a full, clear, and exact description of the same, reference being had to the .accompanying drawings, and to the numerals of reference marked thereon, which form a part of this s eciication.

This invention re at'es to a process for removing shadows from stereoscopic pictures and particularly to a process whereby pho` tographic negatives or positives, or plates from which stereoscopic ictures are to be printed, may be so treate that no shadows or similar eiects along sharp lines of demarcation between contrasting portions will be evident when the picture is viewed stereographically.

The process disclosed herein is especially applica le in connection with the production of two-color stereoscopziuc pictures such as are 'described in my atent 1,326,720 granted August 9, 1921. This method of stereoscopic portrayal consists of printing the right and left eye views of the stereoscopic picture in complementary colors in vsuperimposed relation, and in viewing the resultant picture throu h suitable color screens which are adapte to shut oif a different one of said complementary colors The complemental views 'of any given stereoscopic picture do not exactly coincide when superimposed and it is evident that when a lshadowon one of the views overlaps or is adjacent to a high light on the complemental view, the complementary colors will not be entirely faded out but one of them will predominate and a sharp line ofl demarcation of the predominating color will be visible v where high lights and shadows are contignous along the overlapping portions.

The above effect may in certain instances bepartially overcome by printing the picture in colors which. arel not of thev same complementary value, but this matter involveslthe obJectionable feature of the appearance of the entire picture in the redominating color due to the incomplete ading of thecolors and consequently renders Shadows from Stereo-A Serial No. 460,432.

impossible the production of. true black and white plctures. If color screens of suiciently heavy colors to fade out the objectlonable shadows are used, the picture is apt to appear indistinct when viewed therethrough.

It is an object therefore of this invention to provlde a process for the production of superlmposed two color stereoscopic pictures whereln adjacent contrasting portions will not produce a noticeable line of demarcation when the picture is viewed stereoscopically.

It is also an important object of this invention to provide a process whereb stereoscopic pictures comprising comp emental views, which are printed m superimposed relation in complementary colors may be produced in such a manner that the resulting picture, when viewed stereoscopically through proper color screens, appears in black and white.

Other and further important objects of this invention will be apparent from the disclosures in the drawings and the accompanying specification.

The process of this invention is diagrammatically illustrated on the drawings and hereinafter more fully described.

On the drawings:

Fig. 1 is a diagrammatic representation of the first step in preparing the left eye component of the picture.

Fig. 2 is a similar representation for the right eye component.

- Fig. 3 is a diagrammatic representation of the second step in the process of preparing` the left `eye component of the picture.

ig. 4 is a similar representation for the ri ht eye.

ig. 5 is a diagrammatic representation of the united components forming the complete picture. '1 The object chosen for illustration is a light disk at a distance in front of a dark background. Fi 1 represents the first step in the prepaatlon of the left eye component of the picture. This may be a printed impression .'on paper, an image on a screen, a photographic negative, a lantern slide, a printing.I block or other means of reproducing, the view. No attempt therefore is made -to show' the article itself, but it is represented: by showing diagrammatically the component 4of the view which can be madel therefrom. Similar remarks apply concerning each of the figures from Fig. 1 to Fig. 4 inclusive. Figure 5, on the other hand, because it represents the components as united after all the steps in the process are completed, shows the actual picture.

A s shown on the drawings:

The reference numeral 1 indicates a photographed object which is positioned forwardly of the background 2 in such a manner that hi h lights prevail on the object and consequently the shaded portions 3 and 4 where the dark colors representing the background 2 overlap the light area represent ing the object 1 when the two component views are combined into the stereographic picture. It is these overlapping portionsY that if the process described herein is not followed, give use to shadows when the picture is viewed stereographically. This 1s due to the line of demarkationbetween the predominating color and the background, or between said color and the object, as the case may be. .In other words, the colors along said overlapping portions are not completely faded out by their complementary color, and the rocess 'of this invention provides means w ereby this line of demarcationwmay be eliminated.

As a specific illustration of this invention consider the case where a light colored disk y at a distance in front of a dark colored background is to be stereographically represented. Assume that thegoggles used are reen in front of the ri ht eye and red in ont of the left eye. gIhen the left eye component of the stereogram, shownv in Figure 1 will be printed in green. According to the prior art it would consist of only a dark-green background 2 and a white or light-green vdisk 1.

The ri ht eye component would be printed in red. ccording to the prior art it would consist of only a dark red background 2 in Fig. 2 and a white or light-red disk 1 in that figure. If these two components are superposed, the two disks 1 will not register. AInstead the disk 1 from Fig. 2 will overlapthe background 2 of Fig. 1. This overla area is represented at 3. Following the prior art there would be no diference between the area 3 and the rest of the background 2. According to my invention I make a difference by giving to area 3 a lighter character than the rest of the background. In the same way I give to the corresponding area 4 in Fig. 2 a lighter red color than the dark red color forming the rest of the background 2 in Fig. 2.

The goggles used in viewing stereograms are never of exactly complementary colors and the inks used in printing them are not exactly complementary nor do they exactly correspond to the colors of the goggles.

Consequently, it is possible to see some of the red ink through the red side of the goggles and to see some of the een ink through the green side. If this mvention were not employed the eiect of these defects would be that the observer looking through the goggles would see in the background to the right of the disk 1 a faint band of reddish color separated from the rest of the background by a line, which, because it is sharp, is quite noticeable. For the same reason he would be likel to see a faint greenish color to the left o the disk 1 separated from the rest of the background by a sharp line. Since the ink now available can be much more nearly tted to the color of one goggle than the other, the observer will not ordinarily see such lines on both margins of the high lights. With very dark inks in close roximityl to very light spaces, these imper ections give rise to undesirable shadows or ghosts bounded by the aforementioned sharp lines when the picture is' viewed through the goggles. With lighter inks such shadows do not a pear, but the parts of the picture that oug t to be dark will not be if the are completely printed in light inks. invention removes the dark ink in those places where it will mar the stereoscopic elect, but leaves it undisturbed elsewhere.

Usually the stereogram is printed from two plates, one for each component. These plates are most commonly prepared from a pair of photographs. The change in color in the overlap regions V(correspondin to the areas 3 and 4 in the specific illustration) may be brought about in a variet of ways. For example,.the photographs, i positives, may be reduced sli htly over the desired -areasif negatives, t ey may be slightly intensified thereover or darkened there with a retouching pencil. If the invention is applied directly to the printing plates, they may be slightly etched to cause the selected areas to deliver less ink.

It is apparent that by the use of the process of this invention it is possible to print the pictures in inks of the proper complementary colors to completely fade out when viewed through color screens, and consequently the stereoscczpi'c picture may be made to appear in the esired black and white with no colored lines of demarcation at those portions where any shadows overlap( adjacent to high lights.

am aware that many details may be varied in effecting the process of this linvention without departing from the spirit thereof, and I therefore do not p ose limiting the patent granted otherwise than necessitated by the prior art.' I claim as my invention: 1. The process of producing stereoscopic pictures, comprising making a stereoscopic negatlve, making a photoengraving from' each View of the ne ative, eroding certain portions of the potoengravings Where shadows are adjacent high lights, and printing the views from the photoengravings in superimposed relation 1n complementary colors.

2. The process of producing stereoscopic pictures, comprising makin a stereoscopic negative, producing means rom which each view of the negative may be printed i11- complementary colors in superimposed relation, and softening certaln contrasting portions of the pictures as originally photographed prior to printing.

l3. The process of producing stereoscopic pictures, comprising reducing certain extreme contrasting portions of the component stereoscopic images and printin said im- `es in superimposed relationshlp in comementary colrs.

4. The process of producing stereoscopic pictures comprising photographing an object to produce stereoscopic images thereof,v making a photo engraving from each of the negatives, softening certain extreme contrasting portions of the separate images,

yand printing the images from the photo- ALFRED J. MACY. Witnesses:

CARIzroN HILL, JAMEs M. OBRmN.

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