US1225246A - Color photography. - Google Patents

Description

H. HESS.

COLOR PHOTOGRAPHY.

APPucATmN man MAR. 26. 1914.

19%59246@ .Patented May 8,191?.

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ree77/ 3L Grg/. BZacf/ n as la oro HENRY HESS, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR '.llO HESS-IVES COJE POBATION, 03F PHILADELPHIA, PENNSYLVANIA, A CORPORATION 0F VIRGINIA.

coton Pno'roeaar.

Specication of Letters Patent.

Patented May 8j, 519i?.

Applicationled March 26, 1914. Serial No. SRASB.

Photography, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to color photography and more particularly to the multipllcation of color photographic prints. t

The main purpose of the present improvement is to enable the production of an 1ndeiinite number of color photographs or positives, which. may be on paper, from a single color transparency which will usually be a positive, of the true colors, rather than a negative having complementary colors.

In accordance with this purpose it may be possible, for example, to take any color photographic transparencysuch as a lumire autochrome or other positive transparency et `ly made up of minute patterned areas of the primary colors, and reproduce therefrom an indefinite number of colored positives on paper. Heretofore it has been impractical because highly diiiicult and unsatisfactory to produce, in any manner, colored positives on a reflecting back or paper by the use of color photography systems involving composing colors by variously proportioned aggregations of minute color areas.

Other objects and advantages of the pres- -ent invention will be referred to in the hereinafter following description, and other advantages not mentioned will be apparenttov those acquainted with the art.

l will first describe onemode in which the present invention may be carried out and will thereafter set forth thenovel features in the claims. u

A transparency may be employed by whatever process produced, but for the purposes of illustration a transparency will be assumed which constitutes a diapositive composed of minute aggregated dots or lines of the primary colors which will be assumed to be red, blue and green.

As is well recognized, the association of these three colors in various depths or proportions can be made to approximate the whole range of natural colors. For examle, green is produced by excluding or locking out the red and blue rays, and so with the other primary colors; while yellow is produced by association of red and green, the blue being blocked out, and so with the other secondaries.

Broadly speaking, the present process comprises the steps of'first producing from the multi-color transparency a set of, in this case three, separate -monochrome prints and thereafter combining the monochrome images into a single multi-color positive or print which may be upon paper. l will preferably produce each of the three positive prints by the use of a light lter or col-or screen beneath'which the transparency is placed during printing. Thus a green lter used in combination with the transparency will yield a print representing the green element of the subject. In some cases the positive may be secured only indirectly by rst making a negative from exposure beneath the transparency and screen, and thereafter producing the positive from ,the negative. In any case the member which is printed beneath the transparency may be selectively sensitized to aid the color selection. rlfhe red and the blue will be similarly treated. rlhus three positives are yielded. In some cases the positives may be colored or stained in the complementary colors in a manner well understood so that' in the nished print there will be a yellow component 1representative of the blue-selection negative, etc. The final combiningof the three monochrome color images may be effected in any desired manner, for example, by imbibition of the images into a single gelatin coated paper print, or'by direct superposition of the three images upon a single opaque base.

Specifically ,the process hereof may be carried out as follows. Ccmmencing with the lumire multi-color diapositive we may place a sensitive plate beneath that, a green'lilter above it-and then expose for a sufcient' time,

thereafter developing the plate and so producing a black and white-negative representing the green elements of the picture. l do the same with the red and blue thus securing will be effected by a bichromated gelatin film on-a Celluloid base, the same printed through its transparent base from the green selection negative. Upon Washingv out in .'warm Water the gelatin is partly removed but is retained Where affected by light, thus producing a positive in the nature of a gelatin relief. In preference to employing colored gelatin, I stain the relief after washing out and in this first case the relief will be stained magenta or the complementary of green. The same Will be repeated for the red-selection and blue-selection negatives,

the former giving a blue-green positive and paper back. 0f course', the three components must be carefully registered and, when properly registeredmay be-secured at the edge so as to permit opening and the introduction of a colorless cement so that,upon closing the components together and spread- .ing the cement, a color photograph on paper is obtained in a permanent and durable form.

In some cases the process might be varied by dispensing with the intermediate production of negatives and directly producing the gelatin or other positives from the transparency. The sensitive gelatin exposed behind the transparency with a green screen over the latter may be colored with green,l

either by washing out the unaffected. gelatin and staining the relief or by first saturating l with color and then soaking the color out of the unaffected parts, the color becoming mordanted in the affected parts; thus yielding a green monochrome which may be combined with similarly produced blue and red monochromes.

The process may be varied by suitably simultaneously exposing behind the transparency for the three colors. For example, parallel or other( light rays such as sunlight may be projected through the transparency and the beam of light separated by means of a transparent reflector, one part passing through a green filter, a second partv through a red filter and a third part through a blue filter in the general manner indicated in Patent No. 1,153,229; or two of these, for example, the green and the blue, mightbe produced upon plates arranged face to face, the foremost plate temporarily dyedto serve 4 as a screen for the rearmost in a manner analogous to prior Patent No. 980,961; or by a proper arrangement of plates and color layers, the three might be employed combined in a single plate packin amanner green, that is pink or magenta.

menace similar to prior Fatent No. 927,244, thus dispensing with transparent reflectors.

Although the invention above describedis not capable of full illustration by drawingsnthe successivesteps or changes involved in carryingv out the process may be conveniently shown by a drawing, and to this end a drawing is annexed in which the figures may be described as follows.

Figure 1 represents a supposed transparency in colors. Instead of a picture I have, for convenience, shown a geometrical. pattern containing `the three primaryand the three secondaryvcolors, together with white or clear, gray and black.

Fig. 2 represents a green selection negative made by printing through the transparency by the use of green light or with a green Aglass Lscreen interposed. Similarly, Fig. 3 represents a red selection negative and Fig. 4 a blue selection negative. These negatives are, of course, mere black and white negatives, for example, of silver.

Fig. 5- represents a positive made from the green selection negative of Fig. 2. rIhis positive will be of a color complementary to Similarly Fig. 6 is ablue-green positive made from the red selection negative of Fig.-3, and Fig. 7 is a yellow positive made from the blue selection'negative of Fig. 4. v

Fig. 8 represents the three positives of Figs. 5, 6 and 7 combined or blended in a suitable manner. Fig. 9 is a chart showing the conventional shading representing .the

different colors indicated'on the drawings.-

' The transparency 10, in Fig. 1, is shown as containing a red area or portion 11, a green area 12, a blue area 13, a yellow areax 14, a magenta area 15, a peacock area 16, a

black or'opaque area 19. y

When printing is effected through this transparency by the aid of green' light, we

secure the green selection negative 21, Fig. 2. The green screen permits the light to act photographically upon only those areas which admit the passage of green light, namely, the areas colored green 12, yellow 14, and peacock or blue-green 16, and, of course, clear area 17 and the half clear or gray area 18. This action gives the negative pattern seen in Fig. 2.

A precisely similar action occurs in making the red selection negative 22, Fig.` 3, the red light passing through only the area portions 11, 14, 15, 17 and 18. So also in making the blue-selection negative 23, Fig. 4, the blue light acts only through the area portions 13, 15, 16, 17, and 18.

In making the complementary positives we, of course, secure the reverse of the several negatives. rI`he green selection negative 21, Fig. 2, yields the positive 3 1, Fig. 5, which will be colored magenta or pink, the

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' white or clear] area 17, agray area 18, and a naaaaae complement of green. So also the positive 32, Fig. 6, made from the red selection negative will be colored peacock or blue-green, and the positive 33 Fig. 7, made from the blue-selection negative 23 will be colored yellow or complementary to blue.

On superposing or otherwise blending the positives 31, 32, 33, we secure'the final print 34, Fig. 8. In this print the areal corresponding with 11 consists of magenta and yellow superposed, and, since the only color capable of passing' through strata of magenta and yellow is the primary red, this red color is reproduced at this area, similarly with the other primary areas 12 and 13. rlhe area 14, in the final print, is built up merely of the yellow color in the positive 33, Fig. 7, the other two positives being clear at this area. We thereforeobtain yellow for the area 14. Similar results occur with the other secondary areas 15 and 16. The clear area 17 is clear in each of the monochrome positives and, therefore, is clear or white in the final print. The area 19 is colored in all three of the monochrome positives and, as each one of them subtracts its fraction of the light, the sum of them subtracts all of the light, giving black or opaque. 'llhus the final print is a duplicate of the original transparency throughout every portion thereof.

1t will thus be seen that 1 have described different embodiments of the present invention, attainingthe objects and advantages above set forth. Since various of the features may be modified without departing from the general principles, no limitations to such features are intended excepting so far as speciedin the appended claims.

What is claimed is:

.1. In the art of color photography, the method of producing multi -color prints from a multi-color dia ositive comprising preparing a plurality o separate negatives by exposing through the diapositive to lights respectively corresponding to the different primary oolors of the diapositive, preparing from said negatives a plurality of corresponding monochrome positives each having the complementary color of the light with which the correspondin negative was produced, and thereafter com ining the resulting monochrome images to form a multi-color print.`

2. In the art of color photography, the method of producing multi-color prints from a multi-color diapositive, comprising preparing a plurality of separate negatives by exposing through the diapositive to light-s respectively corresponding to the different primary colors of the diapositive, printing from each of said negatives a corresponding positive, each positive consisting of acolloid relief, printed through its base and washed, and staining each positive to correspond in color to the complement of the color With which the corresponding negative was produced, and thereafter combining such monochrome images to form the multi-color print.

3. ln the lart of color'photography, the method of producing multi-color prints from a multi-color transparency comprising preparing a plurality of separate monochrome positives from the transparency by the exposure therethrough of sensitized members to li hts respectively corresponding to the di erent primary colors of the transparency, giving each positive a color complementary of the light to which it was exposed by the incorporation therein of suitable coloring matter, and thereafter combining such monochrome images to form the multi-color print.

4. ln the art of color photography, the

'method of producing multi-color prints from a multi-color transparency comprising preparing a plurality ;of separate colloid relief positives from the transparency by exposure therethrough and through their bases of sensitized colloid members to lights respectively corresponding 4to the different primary colors of the transparency, washing and staining each positive a color complementary to the light to which it was exposed, and thereafter combining such monochrome images to form the multi-color print.

In testimony whereof I afix my signature in presence of two Witnesses.

HENRY HESS.

Witnesses: n

vBELLE KENNEDY,

MARY M. CALLA.

Images