US1162162A - Process of producing printing-plates. - Google Patents

Description

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" mn'nn'n i1. arr, or'BRIoo KLYN, new "rank.

To allw homit mag concern:

Be it known that I, MaBEL HA'r'r, a' citizen of the United. States, residing at Brooklyn, in the countyof Kings and State of New York, have invented certain new and useful Improvements, in" Processes of .Producing Printing PlateS, ,of which the following is a specification. z a

The inventionrelates to a process of making printing plates photo mechanically, and more especially to a process for producing photo-mechanically printing plates for three color. work, and the invention has for its objects the production photosmechanic'ally of 'color plates which are substantially correct a in their color representations or color values,

and which do not require, a large amount of the usual after treatment-or hand work which is ordinarily necessary in preparing are complementary to theprintingcolor Also, but in a lesser degree there is an excess of the color 'inwhich the plate is to be printed in those parts of the picture which may be called partially complementary to the printing coloru As an example, in the plate which is used to print the magenta color, it will be found that by pure photographythere is a very great excess of the magenta 1n the greens and "that there. is'also an excess of the magenta, although ina lesser degree, in the greenish blues and the yellows. In other "words, the plate which is made for the magentacolor is too full infthe green of the picture in a. comparatively marked degree, It is 'likewisejtoo full,- although in a lesser degree, in thejpeacock blue and allied colors of the picture,"'and this is likewise true with respect to-"the yellows of the picture, although in a still lesser degree with regard to theselatterI The plate for printing the blue may begotten very nearly correct by the use of the red, color. filter and maybe regarded as correct within practical boundsor limits,'and

from hand work on the plate. P

rnocnss' or PRODUCING PRINTING-PLATES.

' Specification of Letters Patent. Patented-NOV. 30, 1915 Application filed May a, 19 13." SerialNo. "266,543. I p I j where this plate is out at all it will be found too full in the reds.

The plate for printing the yellows as made photo-mechanically with the violet glflor. filter is usually not as correct as the 4 ue.

This yellow plate is "too full in the violets, thepurples and the blues, that is, as made by the color filter it will impart too much yellow in the print to the violet tint and the purple tints and the blue tints which are built up by superimposition of one, printing upon the other, and which may be considered as the secondary colors of the printings. The greatest excessi'n theplate for the yellow will be found in the violet.

In accordance with the present invention there is provided a corrective to the light in connection with the creation of the screen figure upon the negative, whereby the excess -.or objectionable fullness is eliminated from the negative, instead of from the printing plate itself, and furthermore, this is done in the case of the presentinvent-ion by the process photo-mechanically as distinguished Thus not only is expensive corrective work on the plate avoided, but the correction is made once for all in the negative and is thus ef fected and completed for any desired number of printing plates which may be made from that negative, whereas in the old form I the corrective work in addition to being done expensively by hand has to be done for each successive plate made from thenegative.

In carrying out the process of my invenw tion, the subject to be reproduced is positioned or posed before the camera in the usual manner. The color filterfor the complementary color to that in which the plate is to be printed is employed to cut out the other colors which are not desired in the particular plate for which the negative is being made. By way of example, if V the plate to be made is the plate for printing the magenta, the green color filter will be used.

Before thesensiti zed plate in the camera a half tone screen is inserted, the rulings or tintings of which are partially light transmitting for certain light rays but impervious to other light rays. That is, the tintin s or rulings are'translucent'and of 'a 00 or which is corrective of the errors oraberrations of the plate already described.

Referring again to the making of the ma Tgenta plate, a half tonescreen would be used having its lines and rulings of a greenish color and having the differentareas thereof of different degrees of light transmitting power. This screen will have the effect ofexaggerating the light action of the greens,

blues and yellows in the magenta negative.

It willbe understood that I thus secure a differential action at. the plate and change the ratio of the various light rays which have passed the color filter so as to emphasize the greens and blues and yellows in the plate and thus correct the fullness. of this plate in these colors.

Inmaking the half tone negative, I prefer the employment of a direct method of color photography, either with collodion emulsion or on color sensitive. gelatin dry plates. The surfaceof the copper or other printing plate to be made from the negative may be "sensitized in any of the well known ways, and the various steps of making the plate proceeded with in the usual manner only that the corrective hand work necessary use such a half tone screen as I have already for reducing the fullness of the plate, and especially the. magenta plate, as heretofore described, is obviated;

' In carrying-"out the invention I prefer to described having also the features of the Hatt highlight screen patented to J. A. H. Hatt July 8, 1913, by United States Patent By the use of a medium, such as the half tone screens with the translucent colored the printing plate.

tintings or rulings, I am enabled to get the desired modified action on the surface of That is, the-full light which is passed by the color filter, taking for instance the green color filter, is permitted to act on separate, small and closely contiguous areas of the sensitized plate or negative represented by the clear glass transparent portion of the screen figures, and the green light, or a portion thereof, is permitted to ass more easily in the areas or portions of the screen which are of a greenish color and which will give the necessary eifect in the greens, blues and yellows as printed from the magenta plate. The oiiice or effect of the greenish half tone screen in the case of the negative for the magentaplate would be equivalent, so-far as its effeet on the final picture is concerned, to

make the greens, blues and yellows of the copy or original, brighter and give them more actinic value on the negative and thus by photo-mechanical means bring the printed picture into truer relation to the copy.

Where it'is desired only to correct the -magenta plate, the corrected half tone screen for this color may be also employed for the other colors, as it will have no effect upon the blue or yellow negatives, for the reason that the green screen is practically opaque to the violet light used for the yellow negative and the red light used for the blue negative. It will be understood therefore that. by my process I modify the plate photo-mechanically to compensate, for variation from the ideal colors of the actualinks obtainable for and workable in printing.

The printing plate is then madefrom the sensitized plate in the usual manner and the various printings are made upon the im pression receiving material to constitute the complete picture, as hereinbefore indicated. It will be understood that while I have described the preferred manner of carrying out my process. ofv my invention, that changes. may be made therein within the scope of the accompanying claims without departing from the principles of the invention.

What I do claim as my inventiomand desire to secure by Letters Patent, is:

1. The process of producing-a photo-mechanical printing plate for printing in colors which comprises photographing the original through a suitable color filter onto a sensitized plate which is. to constitute the half tone negative for the desired color and interposing before said negative an instrumentality which will change the relative action upon the plate. ofthe various component rays of colors of the light which has passed through the color filter, and making a printing plate from said sensitized plate after it has been so exposed.

2. The process of producing a photo-mechanical printing plate for printing in colors which comprises photographingthe original through a suitable color filter onto a sensitized plate and interposing before said negative an ins'trumentality which will change the relative action upon the plate of the various component rays or colors of the lightv which has passed through the color filter, and making a. printing plate from said sensitized plate after it has been. so exposed.

4. The process of producing a photo-mechani'cal printing plate for printing in colors, which process comprises photographing an original through a suitable color filter on to a sensitized plate and interposing be tween said color filter and said sensitized plate a half tone screen having rules or tintings which permit a part of the filtered light to pass and prevent other parts thereof from passing, and making a printing plate from said sensitized plate after it has been so exposed.

5. The process of producing a photo-mechanical printing plate for printing in colors which process comprises photographing an original through a suitable color filter on to a sensitized plate and acting on the filtered light between'said color filter and said sensitized plate to render some of its component colors brighter with respect to the other component colors thereof, and making a printing plate from said sensitized plate after it has been so exposed.

6. The process of producing a photo-mechanical printing plate for printing in colors which process comprises photographing an original through a suitable color filter on to a sensitized plate and interposing between a said color filter and said sensitized plate a screen having translucent rulings or-tintings which rulings or tintings transmit to the sensitized plate certain thereon of the filtered light rays and arrest other of the filtered lightrays falling thereon and making a printing plate from said sensitized plate after it has been so exposed.

7. The process of producing a photo-mechanical printing plate for printing in colors which process comprises photographing an original through a suitable color filter on' to a sensitized plate and interposing between said color filter and said sensitized plate a screen having translucent rulings or tintings which rulings-or tintings transmit to the sensitized plate certain thereon of the filtered light rays and arrest other of the filtered light rays falling thereon, the open spaces of. the screen between the rulings or tintings transmitting all the filtered light falling thereon on to the sensitized plate, and making a printing plate from said sensitized plate after it has been so exposed.

8. The process of producing a photo-mechanical printing plate for printing the magenta color in a multi-color picture, which process comprises photographing a colored original through a green color filter on to a sensitized plate and interposing a screen between'said filter and sensitized plate which has greenish translucent rulings or tintings and clear or open spaces therebetween, and

7 making a printing plate from said sensitized tized plate, and making a printing plate 7 I from said sensitized plate.

10. The process of producing a photo-mechanical printing plate for printing incolors, which process comprisesfiltering out one of the colors of the original, and modifying the actinic action of another of thecolors upon a sensitized plate. I

I 11. The process of producing a photo-mechanical printing plate for printing in colors, which process comprises making a plurality of printing plates for the various colors by filtering out other colors, and varying or modifying the actinic effect of the various colors in making the various printing plates.

12. The process of producing a set of mechanical printing plates for printing in superimposition in colors, which process comprises making a printing plate for each of the colors to be printed in superimposition by filtering out for each plate all but the particular color for said plate, and modifying the actinic efiect of each of the said colors upon its particular plate.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

MABEL K. HATT.

lVitnesses JOHN D. MORGAN, Boss MENK.