US2276718A - Method for producing half-tone reproductions - Google Patents

Description

March 17, 1942. H. M. CROSBY METHOD FOR PRODUCING HALF- TONE REPRODUCTIONS Filed March 31. 1941 Patented Mar. 17, 1942 METHOD FOR PRODUCING HALF-TONE nEPaopUo'rroNs Harold M. Crosby, Flushing,-N. Y., assignor to News Syndicate Co. Inc., NewYork, N. Y., a corporation of New York Application March'31, 1941, Serial No. 386,002

' .4 Claims. (01. 41-41 Myinvention relates to-a new and improved method for producing half-tone reproductions.

One of the objects of the invention is to provide improved means for preparing the copy in chromatic color, so as to make it unnecessary to use dyes or pigments for this purpose.

Another object of my invention is to provide a new'and improved method for producing the copy for making a half-tone negative which is known in the art as a highlight drop-out.

Another object of the invention is to provide an improved method of preparing the copy for use in the processes which are set forth in my application Serial No. 344,845, filed July 11, 1940, and in my application Serial No. 368,186, filed on December2, 1940. a 7

Other objects of the invention are set forth in the annexed description and drawing.

Heretofore, advertising copy of the art work type has been supplied to a: newspaper or other According to the first method, I impregnate the sheetof paper or board on which the copy is prepared with an aqueous solution of para-nitrophenol. This solution is prepared by dissolving 100 grains (avoirdupois weight) of para-nitrophenol in 2 quarts of water. I also preferably dissolve grains (avoirdupois weight) of citric acid in the water. Since one pound avoirdupois is equal to 7,000 grains, and since the weight of a gallon of water is 8.3359pounds, said solution contains substantially of the para-nitrophenol by weight. The citric acid is used in order to stabilize the solution of the para-nitropublication, in the form of a drawing in black or gray color, on white copy paper or copy board.

Said drawing almost invariably has areas to i which little or no coloring matter has been applied. These areas are designated asthe extreme highlights."

In the aforesaid applications Serial No., 344,- 845, and Serial No. 368,186, I have disclosed the idea of producing the. color tones of the copy,

save in the very dark tones, in a chromatic color,

such as yellow, yellow-green, etc; I have also disclosed the use of pigments or the use of watercolors.

The drawing illustrates a subject which has been reproduced by printing with a half-tone phenol and to maintain the same colorless. Otherwise, the solution assumes a yellow color, upon standing. The citric acid is used in suflicient proportion to maintain the pH of the solution slightly below '7.

After the copy paper or copy board has been thoroughly saturated with this solution, the

water is preferably evaporated so that dry copyv paper or copy board is supplied to the artist. It is unnecessary, although it is preferable, to evaporate the water from the copy paper or copy board.

A yellow color can then be developed by reacting the para-nitro-phenol or its aqueous solution, with an aqueous solution of a suitable alkali,

dyes, including such as sodium hydroxide or potassium hydroxide or the like. This solution can be'made by dissolving 50 grains (avoirdupois weight) of sodium hydroxide in two parts of water. 2 ounces of sodium carbonate can also be dissolved in the water, although the sodium carbonate can be omitted. If the entire surface of the copy paper or copy board is first impregnated with the solution of the para-nitro-phenol, the paper can be printed subject consist s er areas 4 which are' printed in middle or intermediate tone. The printed subject also has areas 5, which are printed in'blacktone. Instead of producing these tones for the original copy or subject in black and white, or in gray and white, said tones are produced in said original copy or subject in a suitable chromatic color, such as yellow, save for the very dark tones, which may be produced in black. The original copy therefore has no black or grey, save in the very dark lines or areas 5,

' which are drawn in black, and save for the outline of said original copy I According to this invention, the copy can be prepared according several methods.

thoroughly dried, and the artist can make his outline drawing thereon. If desired, the outline drawing can be made before the copy paper or copy board is treated with the para-nitro-phenol. The aqueous solution of the alkali can then be applied by means of a brush or in any other convenient manner, to all the areas of the copy, except the highlight areas. This produces a uniform yellow color tone in all the areas of the copy, save for the highlight areas. This color tone is of suitable brightness and density, due to the proper proportioning of the para-iiitro-phenol and the sodium hydroxide or the like. After the paper has been dried, or before it has dried, the darker tones can be produced in the respective areas-of the copy. by using black or dark pigments in varying proportion. I can use lamp black or any suitable grey or black pigment.-

pension, such as the well-known water' colors. The areas 2 of the copy which correspond to the light half-tone areas are not treated with the darkening pigment or pigments. Such darkening pigment or pigments are fapplied in increasing proportion to the areas of the copy which correspond to the middle or intermediate tone, the dark-half-tone, and the dark tone. The color tones of the respective areas of the copy thus correspond to the color tones which are to be produced by half-tone printing.

If desired, the artist can first prepare a line copy, which will indicate the various areas thereof and the outline of the copy, and the copy board or copy paper can then be treated so as to develop the yellow color, save in the highlight areas of the copy.

The above method may be reversed, by initially treating the copy paper or copy board with the solution of the alkali, and then subsequently using the solution of the para-nitro-phenol. The solution which is first applied to the copy paper orcopy board may be designated as the initial solution, and the second solution may be designated as the developing solution.

As another alternative, the solution of the alkali may be intermixed in varying proportion with lamp black and other dark pigments, so as to form a number of batches of the alkali solution of varying darkness. These batches can then be 2,276,718 These pigments are preferably in aqueous susmuch more even and fia't in tone, than if a p ment or dye is utilized. Likewise, 'the time and expense of producing the original copy in chro-' matic color is greatly diminished.

For convenience, the areas of the original subject or copy which correspond .to the highlight areas of the printed reproduction may be designated as the highlight areas of the original subject, and the respective areas of said original subject or copy may also be designated as light, intermediate, dark and black.

Whenever -I referto copy paper in a claim or claims, I include any suitable absorbent material on which the original copy is prepared.

It is well known that numerous color eifects can be secured with the use of various indicators, such as phenol phthalein and the like, but the development of a bright yellow color by the reaction above described is much superior for the specific purpose herein stated.

I can use meta-nitrophenol, as an equivalent for para-nitrophenol.

I have shown preferredembodiments of my, invention, but it is clear that-numerous changes and omissions can be made without departing from its spirit.

I claim:

- 1. A method of preparing original copy on paper for use in making a highlight drop-out, which consists in producing a'yellowchromatic tone in selected areas of said original copy, with the exception of the highlight areas of said original copy, "by reacting para-nitro-phenol and the solution of an alkali in the selected areas of the The copy Paper or copy board is thus free of the initial solution, save at the respective nonhlight areas thereof. The developing solution, free from darkening pigment, can then be sprayed or otherwise applied over the entire surface of the'copy paper or copy board, since the yellow color will not be developed save in the predetermined areas of the copy. This is preferable, because it eliminate the danger of overrunning of the color, and this method is more convenient.

After the original copy has thus been prepared by any of the alternative methods above mentioned, the subsequent steps of producing the half-tone negatives are the same as those stated in either of the aforesaid applications Serial No. 344,845 and Serial No. 368.186.

Whenever I referto the use of darkening pigment, I include the use of any coloring matter, including a dye or dyes.

Since the areas of th copy which correspond to the printed black areas 5 are in deep black tone, it is unnecessary to develop the yellow color in said respective areas. ofthe original copy or subject.

- The use of a developed yellow color, as, above mentioned, is much superior to the use of a yellow dye or yellow pigment. The developed color ispaper.

2. In the art of preparing original copy on paper for use in making a highlight drop-out, said original copy haying highlight areas and having other selected areas which are darker than said highlight areas, that step which consists in producing a yellow color in said selected areas by first applying an initial solution only to said selected areas of the copy and then applyin a second solution to all the areas of the copy, said first and second solutions being respectively selected from a class which consists of a solution of para-nitro-phenol and a solution of an alkali.

3. In the art of preparing original copy for use in making a highlight drop-out, said original copy having highlight areas and having other selected areas which are darker than the highlight areas, that step which consists in producing a yellow color tone in said selectedareas by reacting para-nitro-phenol and an alkali in said selected areas.

4. A method of producing original copy on paper for use in making a, highlight negative, said original copy having highlight areas and having a plurality of series of selected areas of successively darker color tone, which consists in producing a yellow color tone in said selected areas by reacting para-nitro-phenol and an aldesired color tones thereof by coloring matter' whose tone is darker than said yellow color.

HAROLD M. CROSBY.

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