US1766426A - Poration - Google Patents

Description

June 24, 1930. L V. cAsTo PROCESS FOR THE REPRODUCTION OF THE NATURAL APPEARANCES OF ARTICLES ON OTHER SURFACES Filed NOV. 23, 1927 F'I err 2 Patented June 24, 193% -ZI'LILOYID V. CASTO, OF DETROIT, MICHIGAN ASSIGNOR PORATION, OF DETROIT, MICHIGAl\T,-A CORPORATION OF MICHIGAN PROCESS FOR THE REPRODUCTION OF THE NATURAL ARIPEARANCES OF ARTICLES 011' i OTHER SURFACES Application filed November as, 1927. Serial No. 235,196.

This invention is concerned with the art of reproducing or-simulating the natural surfaces or appearances of articles such as wood, marble, etc., and has for its general object, the provision of a method .of reproducing in accurate tonal detail the contrasting contours and shades of the surfaces of natural bodies upon the surfaces of bodies which-are formed of dissimilar'materials,the invention being in the nature of an improvementin the photogravure process now being utilized for the reproduction of wood graining upon flat metallic surfaces.

More specifically, my invention is con-- cerned with the production of photogravure rolls or platesin such manner as to obtain practically all of the tonal contrasts of the surface appearance to be reproduced. Other objects of my invention will hereinafter be-' come apparent from the following description of my method of producing such plates or rolls. The essential characteristics are summarized in the claim. I

In the drawings, Fig. 1 represents the first stage of producing a master drawing; Fig. 2 represents the second stage of producing such a drawing, and Fig. 3 represents acompleted master drawing.

In order to more clearly set forth my presentmethod of engraving photogravure plates and "rolls for the purposes hereinabove set I forth, I will first briefly describe the method hereinabove utilized in engraving photogravure plates and rolls for the reproduction of wood grain on smooth hard surfaces of me tallic sheets. When it is desired tov obtain or reproduce the grain effect or appearance of a-"quarter oak panel, butt walnut, etc., a

- wooden panel is first made, the grain of which has been carefully selected for proper grain contrasts and the panel surface is stained with a liquid stain, the color of which has been carefully predetermined to bring'about the desired accentuation ofthe panel grain.

The panel is preferably of the same size or dimension as the surface dimension which is to have the grain reproduction effected thereon, and commercial requirements are such that the panels and correspondingly the engraved plates or roll surfaces are usually adhering not less than 30 K 60 and frequently as extensive in area as 38 x 80". The wooden panel or master panel is then surfaced with TO THE oxronn VARN'ISH cona selected varnish to tone the stain previousof the stained surface of the panel.

An unusually large photographic appa-' ratus is'then used to obtain a photographic negative film or plateof the same dimensions ,as the master panel. A positive is then made from the negative, and from the positive, a

carbon resist is made by the interposition of r a photographic screen, and the photogravure roll or plate is then etched through the carbon resist in the usual roll thus made is utilized by applying ink or pigment to the engraved surfaces thereof, the surface ink being removed by the use of a doctor blade, thus leaving ink in the minute pockets of the engraved surface. The .pattern is removed from the'plateby the use of a gum roll; each minuteportion of pigment to the roll surface in conformity with the arrangement of engraving on the plate. The roll is then passed over the surface to be finished or grained, and the prearranged pattern is thus transferred thereto. Some striking simulations of natural grains have been reproduced by the foregoing described process, but extreme care must betaken in all of the various steps from the selection of the wood of the master panel manner. The plate or to the final operation of transferring the pattern to the surface to be finished. Particular study has been given to the composition of. the stain applied to the master board, the.

glossing of the surface thereof, the preparation of the photographic films or plates be fore exposure, the functioning of'the photographic apparatus, the reproduction of the positive carbon resist, and the character of the etching 'acids:

Despite all of this effort, some of the quarter tones and half tones present'in the original'rnlaster board are lost due primarily to i the lack of light contrast between the back or ground colors of the master board .and the full tones accentuated in the ground lights or colors of the stained board, thus necessitating slow tedious hand-engraving or retouching under a magnifying glass of the minute and relatively shallow pockets which should be present'in the final etched plate result, and which are thus lost.

I propose, therefore, to first prepare the panel in the manner described, and while using this panel as a subject to prepare a drawing thereof on parchment or paper, the color of which, relative to'the grain tones, will rovide a marked over-contrast, and then I p otograph the drawing and produce the plate by the subsequent steps of the process described, during which the over-contrast is slightly diminished in each of said steps of the process, and in the final etching step, all of the details of engraving will be properly produced on the plate or roll surface to effect the final reproduction of the several fractional tones present in the original master board.

In Fig.1 of the drawings I show the beginning of a master drawing with full tone or outstanding lines 10, which may be elfected thereon by manual effort or through photo- I ing being of the same dimensions as the masgraphic means, the coloring of the paper being preferably of a li hter shade than the back or ground color of the master board. I then carefully draw upon this master drawing half tone lines 12, (see Fig. 2) and next carefully produce quarter tone-lines 14 and finally lesser contrasting tones 16, this drawter board. It is to be understood that if desired the board may be ruled into guiding squares or zones, preferably inch squares, and the paper or parchment drawing correspondingly lightly ruled.

I then place the drawing on a mounting means in the illuminating gallery and produce therefrom in the manner described, a full size negative fromwhich positive and carbon resist are made as hereinabove set forth. Each succeeding step gradually decreases the over-contrast and then the etching is effected by the artist upon the plate or roll, and the entire surface is simultaneously etched without necessitating acceleration and retardation of the etching action of the acids over various zones of the surface being etched.

A photogravure plate or roll made in the manner described will have screen pockets reproduced thereon which have been heretofore unobtainable regardless of the degree of care exercised in the various operations of producing the plate or roll and in the selection of the various materials used in carrying out the process. For example, in reproducing a butt Walnut I may obtain as high as five distinct tonal contrasts in one transferring operation of the pigment from the plate 1,7ee,42e I to the surface to be grained which tonal contrast heretofore has either been lost or so nearly completely subdued in the ground color that the optical e'ifect has been lacking.

I claim:

The process of reproducing photogravure plates and rolls which includes the steps of preparing-a master drawing of the surface appearance of an article which surface appearance is to be simulated on other articles and forms of dissimilar materials by filling in on the master drawing over-emphasized full tone, half tone, quarter tone and under tone shades corresponding to and in configuration with the full tones, half tones, quarter tones and under tones of the configurations of the surface of the subject whereby said drawing may be utilized to produce a full sized carbon resist by the photographic process and the signature.

LLOYD V. CASTO.

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