US2339481A - Process of producing dropout halftone positives - Google Patents

Description

Jan. 18, 1944. A. L. HUT TKAY 2,339,431

PROCESS OF PRODUCING DROP-OUT HALF-TONE POSITIVES Filed March 6, 1942 INVENTOR 7 Patented Jan. 18, 1944 PROCESS OF PRODUCING DROPOUT HALFTONE POSITIVES Arthur L. Huttkay, Newark: J. Application March 6, 1942, S erial No. 433,531; 17 .Claims. (01. 95-5) This application is a continuation in part of the U. S. patent application Serial No. 378,221, filed February 10, 1941.

This invention relates to new and improved processes of preparing printing plates, and more particularly relates to processes of producing drop-out half-tone positives and negatives by eliminating all half-tone screening dots in the background or highlight sections of half-tone positives and negatives. These processes are particularly adaptable for the type of photo-engraving and illustration commonly used for newspaper advertising.

the line sections entirely transparent or white. In the sameway the term positive? designates photographic reproduction on any. kind of photographic materialfl. e on photographic-paper, film or plate, in which the highlight sections of the original drawing are substantially whit or transparent, the tone values of the tone sections An object of this invention is to provide simple processes of highlighting which are free from the prevailing lengthy and inexpe'dient methods,

such as laborious hand-painting or hand-opaquing, or photographing with ultraviolet light, which methods are in many instances impractical and depend upon delicately balanced exposure relationships, and are mostly limited to certain types of drawings.

Another object of this invention is to provide processes which will greatly diminish the necessity of using skilled labor and which will facilitate the necessary manipulation preliminary to making the printing plate.

Still another object of this invention is to provide processes in which substantially no retouching or finishing operations are performed by hand, thus eliminating the necessity of manipulating wet films and of retouching or finishing operations upon the printing plates, and also eliminating the necessity of making a series of exposures upon these plates.

It should be noted that throughout this specification and claims the term highlight sections is used to designate those sections of an illustration or drawing which are required to be print ed in reproduction as pure white. i. e.. free from screen pattern. and is usually used as referring to background or "white" sections of an illustration. The term tone sections refers to the shaded or dark sections of the original illustration or drawing to be' printed in reproduction as hall-tones. The term line sections refers to the continuous opaque lines appearing on the original drawin Furthermore. it should be noted that the term "negative" is used throughout the specification and claims to designate photographic reproductions on any type of photographic material in which the highlight sections of the original illustrations or drawing appear opaque. th tone sections more or less trans-parent or white. and i combined with a white background. ,also be noted, that the term fentire surface as substantially the same as on the original drawing, and the line sections entirely opaque. It is evident that if in the specification and claims superimposed negatives are mentioned, these negatives must, consistof a photographic lightsensitive layer on a transparent base, as for instance, photographic films or plates.

Finally, it should benoted that the term drawing as used throughout the specification and claims should not b limited to the exact meaning of the word drawing, but that this term should also comprehend other illustrations, e. g.. photographic or like illustrations if these are It should used in some; of the claims indicates that not only the tone sections but also at least the adjacent portions of the highlight sections of the drawing are chemically treated by. a reduceror otherwise, this term entire surface should not limit the claims to treatments where the entire highlight s'ection of a continuous tone negative is equally treated, since it is possible to treat certain portions of the highlight sections spaced from the tone sections in another way or not to treat them atall. v

The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, together with additional objects and advantages thereoflwill be best un derstood from the following description of specific embodiments, when read in connection with the accompanyingdrawing in which: q v

Fig. 1 illustrates a type of original drawing having tone and highlight sections; 7

Fig. 2 represents a half-tone negative made from the original drawing shown in Figure 1.

having highlight andtone sections; Fig. 3"represents a continuou tone negative made from the original drawing shown in Figure 1;

Fig. 4 shows a half-tone mask negative made from the continuous tone negative shown in Fi:;- ure 3;

Fig. 5 hows a drop-out half-tone positive made with'the aid of the mask shown in Figure 4 from the original drawing shown in Figure l Fig. 6 illustrates a type of original drawing having highlight, tone and line sections;

Fig. '7 is a half-tone negative of the original drawing shown in Figure 6 having highlight. tone and line sections;

Fig. 8 represents a continuous tone negative made from the original drawing shown in Fig. 6; Fig. 9 shows a half-tone and line'mask negative made from the continuous tone negative shown in Figure 8;

Fig. 10-shows a drop-out half-tone and line positive made preferably with the aid of the mask shown in Figure 9 from the original drawing shown in Figure 6; v

Fig. 11 is a partly-opaque continuous tone negative according to Figure 8 having opaque areas corresponding to the line sections of the mask negative according to Figure 9 having opaque areas-' 'corresponding to the line sections of the original drawing shownin Figure 6;

Fig. 14 is a partly-opaque half-tone and line mask negative according; to Figure 9 having 7 opaque areas corresponding to the tone sections of the original drawing shown in Figure 6;

Fig. 15 is a partly-opaque half-tone negative according to Figure 7 having opaque areas corresponding to the line sections of the original drawing shown in Figure 6;

Fig. 16 is a combined half-tone and line negative having transparent areas corresponding to the line sections of the original drawing shown in Figure 6; and

Fig. 17 represents a half-tone screen of usual type used in connection with the processes described below in detail.

In order to facilitate understanding of the above-enumerated figures, it should be noted that figures by diagonal shading represent tone sections of the original drawings and corresponding areas of the negatives and positives; all dotted areas in the figures represent half-tone areas of the negatives and positives; and finally all areas indicated by horizontal shading represent areas of the positive and negatives made opaque by painting out,,i. e., coating with an opaque substance. I

The above explanation will make'the drawings of the present application so clear and easily understandable for everybody skilled in this art, that further elaborate description of each figure in detail may be omitted.

It should only be mentioned that the half-tone mask negative 4 should have such a distribution of density, that (1) the completely white, i. e.. highlight sections of the original drawing shown in Figure 1 correspond to a very high density in the mask shown in Figure 4 while all tone sections of the original drawing should correspond to substantially transparent mask areas and that (2) there be substantially no difi'erence of tone in the transparent areas of the mask;

in order-to produce a half-tone mask negative meeting these requirements, this negative is produced in the specific embodiment described below by making first a continuous tone negative 3 of the original drawing i, and then treating this continuous tone negative 3 with a preferably subtractive photographic reducer until the tones in tive 5 in the way described below in detail. This reducer treatment is preferably carried out while the continuous tone negative 3 is still wet. For reducing purposes, any reducer of the subtractive type may be used; such reducers have the characteristic feature that they reduce all densities of the developed image by about the same density step regardless of the amount of density. Reducers of this type are, for instance, ferricyanide combined with hypo, a ferricyanide bleaching solution, an acid quinone solution, and ammonium persulfate in solutions free from halogen ions and others.

Although very satisfactory results were obtained by this new reducing process, sometimes the opaque areas of the half-tone mask negative 4 became somewhat translucent; in order to avoid this, it is herewith proposed to treat the continuous tone negative 3 before or after the reducing step with a photographic intensifier. This photographic intensifying is preferably carried out after reducing and results in an intensification, 1. e., darkening of the opaque areas of the half-tone mask negative 4 without influencing the transparency of the transparent negative areas. For this intensifying step, any known type of photographic intensifier may be used, as. for instance, sulphide intensifiers, uranium intensifiers, methol silver intensifiers, silver hydroquinone intensifiers and silver nitrate solutions having a slowly-working reducing agent incorporated therein.

The intensifying step described above may be combined with a bleaching step resulting in a change of' color of the intensified opaque areas of the half-tone mask negative; thus, for instance, by using certain combinations of bleaching and intensifying solutions, it is possible to change the color of the intensified opaque areas from dark grey to a dark brownish red having a density which, from the photographic point of view, is about twice that of a dark grey negative.

In accordance with a preferred embodiment of the present invention, the above-described process oi producing the half-tone mask negative of the type shown in Figure 4 is carried out in the following way:

First, from the original drawing I a continuous tone negative 3 is produced by photographing in the usual way. Then the developed continuous tone negative 3 is treated while still wet,

with a fairly strong solution of potassium ferricyanide. This treatment is continued until all areas of the negative which correspond to tone sections of the original drawing are substantially transparent. The thus produced half-tone mask negative 4 is then removed from the potassium ferricyanide reducer-bath, washed and finally placed in a mild hypo, e. g, tion. After repeated washing and drying the half-tone mask negative is ready for use. A]-

though-it is possible to attain with a thus produced half-tone mask negative satisfactory results, it has been found that intensifying of the thiosulphite, soluopaque mask areas is of advantage. i1 and the white sheet ried out by again placing the half-tone mask negative produced in the above described way in a reducer, .i. e., potassium ferricyanide bath and bleaching the opaque negative areas until they appear almost transparent; at this moment a slight image can be seen=when the negative is held against a black background. Thereafter, without subjecting the thus reduced half-tone mask negative to a hypo treatment, it is put into an intensifier bath, e. g., sodium sulphide solution. This intensifier intensifies the previously dark grey opaque areas of the half-tone mask negativeand gives these areas. a brownish red color having twice the photographic density of the dark grey areas before intensifying. After washing and drying the thus intensified halftone mask negative 4 is ready for use.

In some cases it proved advantageous to retouch the original drawing before making the continuous tone negative, e. g., by darkeningthe,

lightest tones of the tone sections and/or making its highlight sections pure white, so as to have a definite separation between the lightest tones of the tone section and the highlight sections of the drawing.

It would seem probable that a half-tone and line mask negative 9 may be produced from the original drawing 6 having highlight, tone and line sections without any 'difiiculty in the abovedescribed way. However, it has been found that during reducing the edges of the line areas of the continuous tone negative 8 are attacked bythereby broadening the lines. In

the reducer order to avoid this reducer action, it is herewith proposed to make first the continuous tone negative 8, then to coat those areas of this negative which correspond to the line sections and ad.- jacent highlight sections of the original drawing 6 with a transparent reducer resistant substance, e. g., shellac, and thereafter subject the thus partly coated continuous tone negative 8 to the reducer treatment described above in detail. This shellac or other coating dries and prevent the reducer from attacking ihe edges of the line areas, resulting in half-tone and line mask negative 9, with line areas having a width equal to that of the original lines in drawing 6.

For producing the finished drop-out positives of the type shown in Figures and 10, other intermediate negatives are also needed.v In order not to crowd the-detailed description of theprocesses of producing the finished drop-out positives with unnecessary details, the methods of producing the intermediate negatives needed for these processes will be described below briefly before further proceeding with this description:

The methods of producing the continuous tone negatives 3 and 8 and the mask negatives 4 and 9 have been described above.

The half-tone negatives 2 and 1 are made in the usual way, i. e., by photographing on lightsensitive photographic material the original drawings l and 6 respectively through the half tone screen I1, and 'fiashingf i. e., photographing a white sheet of paper through the same screen on the same photographic material. The Combined half-tone and line negative I6 is made in the same way as the half-tone negative 1, with the sole difierence being that during flashing a transparent sheet of Celluloid or like material, having opaque areas corresponding to 'the line sections of the original drawing, is

placed between the superimposed half -tone screen areas of the drop-out half-tone duced by superimposing upon an unexposed of paper arranged behind the same. a

Figures 11 to I5 show negatives being'partly opaque, i. e., partly painted out, for the purposes of the present invention. .Thus Figure 11 shows a partly opaque continuous tone negative according-to Figure 8 having opaque areas corresponding to the line sections of the original drawing 6; this negative is made by painting out the line areas of the continuous tone negative 8. Figure 12 shows a partly opaque continuous .tone negative according to Figure 8 having opaque areas corresponding to the tone sections of the original drawing 6 and produced by painting out the tone continuous tone negative 8.. The

partly opaque half-tone and line mask negatives "I3 and M, the first having opaque areas corresponding to the line sections and the latter having opaque areas corresponding to the tone sections of the original drawing 6. are made by painting out the half-tone and line mask negative 9, in the way described in connection with negatives 'l l and |2.- The partly opaque halftone negative I5 is produced by painting out the lineareas of the half-tone negative I. '1

Having thus explained the methods of mak-' 'ingall intermediate negatives, the new processes I of producing the finished drop-out positives will be described in the following in detail:

A drop-out half-tone positive of the" type shown in Figure 5 is produced in accordance with the present invention by making fromthe the half-tone negative 2 and the half-tone mask negative 4, superimposing original drawing I,

these negatives upon an unexposed; photographic, light-sensitive material, and exposing this unexposed photographic material through the superimposed negatives 2 and 4; therea'fterfithc thus produced drop-out half-tone positive is'developed, fixedwashedeand finally dried. This positive 5 may also be prolight-sensitive material, the continuous tone "negative 3 and ,the half-tone mask negative 4 and exposing the unexposed light-sensitive material through these superimposed negatives 3 and 4 and thehalf-tone screen ll arranged at a certain distance from these negativesobtaining thereby the required drop-out half-tone positive 5.

It is evident that in this case and in all cases described below in which an original drawing is photo-graphed, or an unexposed photographic material exposed throughhalf-tonescreen l1, this screen has to be'arranged at a certain distance from the light sensitive material unto which the photograph or print is made; this distance varies in accordance with the screen used and the method of its computation is well-known to everybody skilled in this artland therefore does not have to be explained in detail.

One of the methods of producing a drop-out half-tone and line positive of the type shown in Figure 10 comprises the steps of making from the original drawing 6 a partly opaque continuous negative |2,'a partly opaque half-tone negative l5, and ahalf-tone mask negative of the type shown in Figure 4, superimposed on an unexposed light-sensitive material the negatives 4 and I5 andexposing the photographic material through these superini'posed negatives, removing these negatives, superimposing on the thus partly exposed photographic material the nega-' tive l2 and then exposing the photographic material through this negative; the drop-out halftone and line positive I 0 obtained by this method is then developed, fixed, washed, and finally dried.

Instead of the partly opaque half-tone negative l5, the partly opaque continuous tone negative ll maybe used; in this case, however, in

. drawing 6' two negatives, namely, a combined half-tone and line negative I6 and a half-tone and line mask negative 9 in the way described above in detail, superimposing said negatives 9 and I6 on'an unexposed light-sensitive photographic material, exposing said photographic material through said superimposed negatives 9 and I6, fixing, washing, and finally drying the thus 1 produced drop-out half-tone and line positive l0.

Various modifications of the'above described processes and combinations of the same with other well-known methods are possible. Thus, for instance, it is sometimes necessary, particularly when the tone sections of the original drawing contain very dark portions, to perform in combination with the step of making a half-tone negative another operation which is universally used andis called flashing. Without this flashing, therewould be no screening in the darker portions of the half-tone areas of the negatives because the corresponding sections, of the original drawing reflect little or no light. The purpose of the flashing is to create this screening in the lighter, half-tone areas of the negative. If this flashing operation is used for producing combined half-tone and line negatives of the type shown in Fig. 16, it cannot be performed in the usual way as the screening would appear not only in the half-tone areas but also in the line areas of the negative; the continuity and transparency of these line areas would thereby be broken up and the object of the present invention defeated.

Therefore, when the combined half-tone and line negative IB is produced by photographing the.

between this sheet of paper andscreen I! a 'transparent sheet of. Celluloid or like material which is opaqued, i.

e., painted out, at those areas which correspond to the line sections of the original drawing 6. In this way, in the line areas of the combined negative l6 and in the corresponding areas of the finished drop-out half-tone and line positive l0, screening dots caused by flashing may be avoided.

Although the above-described embodiments are the preferred ones, modifications of the new processes within the limits of the present invention are possible. Thus, for instance, it is possible to reverse the photographic steps in all processes where the drawing isphotographed consecutively through two masks or mask combinations. posures may be reversed when, in one of the above-described processes, a light-sensitive photographic material is exposed consecutively through two masks or mask combinations. Fur- In the same way the sequence of ex-' photographic fixing,

thermore, it should also be mentioned that the 7 term original drawing having highlight and tone sections does not preclude that this drawing has also other sections. It is also self-evident that instead of exposing light-sensitive material through a half-tone and line mask negative of the type shown in Fig. 11 it is always possible to .use a half-tone mask negative of the type shown printing plates, but in general for any purposes whatsoever.

What is claimed as new is:

1. A process of producing a drop-out half-tone positive comprising the steps of making from an original drawing having highlight and tone sections 9. half-tone negative in the usual way, making from the original drawing a continuous tone nega'tiveftreating said continuous tone negative with a photographic reducer until the tones in those areas of the negative which correspond to the'tone sections of the original drawing substantially disappear, fixing the thus produced half-tone mask negative, superimposing said half-tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate, or paper, and making a drop-out half-tone positive by exposing'said unexposed photographic light sensitive material through said superimposed negatives.

2. A process of producing a drop-out halftone positive comprising the steps of making from an original drawing having highlight and tone sections a half-tone negative in the usual way. making from the original drawing a continuous tone negative, treating said continuous tone negative with a reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus treated negative, bleaching it thereafter, intensifying the thus produced half-tone mask negative without intermediate thereafter superimposing said half-tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. film, plate, or paper, exposing said unexposed photographic light sensitive material through said superimposed megatives, developing. fixing, washing, and finally drying the thus produced drop-out half-tone positive.

3. A process of producin a drop-out half-tone positive comprising the steps of making from an original drawing havinghighlight and tone sections a first continuous tone negative in the usual way. making from said original drawing a second continuous tone negative, treating said ,3 second continuous tone negative with a subtractive photographic reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus produced half-tone mask negative, superimposing said first continuous tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate,.or paper, and exposing said unexposed light sensitive material through said superimposed negatives and a halftone screen arranged at a certain distance from said negatives, obtaining thereby the required drop-out half-tone positive.

4. A process of producing a. drop-out half-tone positive comprising the steps 01' making from an original drawing having highlight and tone sections a first continuous tone negative in the usual way, making from the original drawing a second continuous tone negative, treating said second continuous tone negative witha subtractive reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus treated negative, bleaching it thereafter, intensifying the thus produced half-tone mask negative without intermediate photographic fixing, thereafter superimposing said first continuous tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate, or paper, exposing said unexposed light sensitive material through said superimposed negatives and a. half-tone screen arranged at a certatin distance from said negatives between the exposing light source and said negatives, developing, fixing, washing, and finally drying the thus produced drop-out halttone positive.

5. A process of producing a drop-out half-tone and line positive comprising the steps of making from an original drawing having highlight, tone, and line sections a partly opaque half-tone negative having opaque areas corresponding to the line sections of the original drawing, making from said original drawing a partly opaque continuous tone negative having opaque areas corresponding ,to the tone sections of the original drawing, making from said original drawing, a

' half-tone and line mask negative having opaque portions corresponding to the high-light sections and transparent portions corersponding to the tone sections of the original drawing, exposing an unexposed light sensitive photographic material as for instance, photographic film, plate, or paper in desired sequence through said half-tone and line mask negative and said partlyopaque half-tone negative and then through said partly opaque continuous tone negative, developing, fixing, washing, and finally drying the thus produced drop-out half-tone and line positive.

6. A process of producing a drop-out half-tone and line positive, comprising the steps of making from an original drawing having highlight, tone, and line sections a half-tone negative, opaquing on said half -tone negative all areas corresponding to the line sections of the original drawing, making from the original drawing a continuous tone negative, opaquing on said continuous tone negative all areas corresponding to the tone sections of the original drawing, making from said original drawing, a half-tone and line mask negative having opaque portions corresponding to the high-light sections and transparent portion corresponding to the tone sections of the original drawing, superimposing on an unexposed light sensitive photographic material as, for instance, photographic film, plate, or paper, said partly opaque half-tone negative and said half-tone and line mask negative, exposing said unexposed photographic material through said superimposed negatives, removing said negatives, superimposing said partly opaque continuous tone negative on said partly exposed photographic material, exposing said partly exposed photographic material through said negative, developing, fixing, washing, and finally drying the thus produced drop-out half-tone and line positive.

'7. A process of producing a drop-out half-tone and line positive from an original drawing having highlight, tone, and line sections comprising the steps of making from the original drawing a partly opaque continuous tone negative having opaque areas corresponding to the line sections of the original drawing, making from the original drawing a partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing, making from said original drawing, a half-tone and line mask negative having opaque portions corresponding to the half-light sections and transparent portions corresponding to the tone sections of the original drawing, exposing an unexposed light sensitive photographic material as, for instance, photographic film, plate, or paper-in desired sequence through said partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing superimposed upon said photographic material and then through said partly opaque continuous tone negative having opaque areas corresponding to the line sections of the original drawing and said half-tone and line mask negative superimposed on said photographic material and a half-tone screen arranged at a certain distance from said negatives, developing, fixing, washing, and finally drying the thus produced drop-out halftone and line positive.

8. A process of producing a drop-out half-tone and line positive comprising the steps of making from an original drawing having highlight, tone, and line sections a continuous tone negative,

areas corersponding to the line sections of the.

original drawing, making from the original drawing a second continuous tone negative, opaquing on said latter continuous tone negative all areas corresponding to the tone sections of the original drawing, making from said original drawing a half-tone and line mask negative having opaque portions corresponding to the high-light sections and transparent portions corresponding to the tone sections of the original drawing, superimposing on an unexposed light sensitive photographic material as; for instance, photographic film, plate, or paper in desired sequence said partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing, exposing said, unexposed photographic material through said superimposed negative, removing said negative, superimposing on said partly exposed photographic material said half- I tone and line mask negative and said partly opaque continuous tone negative having opaque areas corresponding to the line sections of the original drawing, exposing said partly exposed photographic material through said negatives and a half-tone screen arranged at a certain distance from the same, developing, fixing, washing, and finally drying the thus produced drop-out halftone and line positive.

9. A process of producing a drop-out half-tone and line positive from an original drawing having highlight, tone, and line sections comprising the step of making from the original drawing a. continuous tone negative, coating those portions of said continuous tone negative which correspond to line sections of the original drawing with a transparent reducer-resistant coating material, photographically reducing the thus treated continuous tone negative until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear and these areas-are becoming substantially transparent, fixing the thus produced half-tone and line mask negative, making from the original drawing a combined half-tone and.

line negative being screened within those areas which correspond to the tone sections of the original drawing and being transparent within those areas which correspond to the line sections of the original drawing, superimposing said halftone and line mask negative and said combined half -tone and line negative on an unexposed light sensitive photographic material, exposing said photographic material through said superimposed negatives, developing, fixing, washing, and finally drying the thus produced drop-out half-tone and line positive.

10. A process of producinga drop-out halftone positive comprising the steps of making from an original drawing having highlight and tone sections a continuous tone negative in the usual way, making from said original drawing a halftone mask negative having opaque portions corresponding to the high-light sections and transparent portions corresponding to the tone sectins of the original drawing, superimposing said continuous tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g. film, plate, or paper, and exposing said unexposed light sensitive material through said superimposed negatives and a halfto'ne screen arranged at a certain distance from said negatives, obtaining thereby the required drop-out half-tone positive.

11. A process of producing a drop-out halftone positive comprising the steps of making from an original drawing having highlight and tone sections a continuous tone negative in the usual way, making from the original drawing a halftone mask negative having opaque portions corduced ,drop-out half-tone and linepos material as for-inst @fifiptb or paper in de'tired eq tone mask negative-and 5 tone negative and then through opaque continuous tone negativefdev oping; ing, washing, and finally drying th 13. A process of producing a drop-outhalf tone and line positive, comprising the steps of making from an original drawing having highlight, tone,-

same consecutively without intermediate photoresponding to the highlight sections and transparent portions corresponding to the tone sections of the original drawing, thereafter superimposing said continuous tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate, or paper, exposing said unexposed light sensitive material through said superimposed negatives and a half-tone screen arranged at a certain distance from said negatives between the exposing light source and said negatives, developing, fixing, washing, and finally drying the thus produced drop-out half-tone positive.

12. A process of producing a drop-out halftone and line positive comprising the steps of making from an original drawing having highlight, tone and line sections a partly opaque half,- tone negative having opaque areas corresponding to the line sections of the original drawing, making from said original a partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing, making from said original drawing a continuous tone negative, treating said latter continuous tone negative with a photographic reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus produced half-tone and line mask negative thereafter, exposing an unexposed light sensitive photographic graphic fixing, said bleaching and consecutive intensifying being carried out before or after said photographic reducing and fixing of said negative and resulting in increase of the opacity of those areas of the negative which correspond to the highlight sections of the original drawing, thereafter superimposing on an unexposed light sensitivephotographic material, as for instance photographic film, plate or paper, said partly opaque half-tone negative and said half-tone and line mask negative, exposing said unexposed photographic material through said superimposed negatives, removing said negatives, superimposing said partly opaque continuous tone negative on said partly exposed photographic material, ex-

- posing said partly exposed. photographic material through said negative, developing, fixing, washing, and finally drying the thus produced dropout half-tone and line positive.

14. A process of producing a drop-out halftone and line positive from an original drawing having highlight, tone and line sections comprising the stepsof making from the original drawing a partly opaque continuous tone negative having opaque areas corresponding to the line sections of the original drawing, making from the original drawing a partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing, making from said original drawing a continuous tone negative, treating said latter continuous tone negative with a photographic reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus produced half-tone and line mask negative thereafter, exposing an unexposed light sensitive photographic material as for instance photographic film, plate'or paper in desired sequence through said partly opaque continuous tone negative having opaque areas corresponding to the tone sections of the original drawing superimposed upon said photographic material and then through said partly opaque continuous tone negative having opaque areas corresponding to the line sections of the original drawing and said half-tone and line mask negative superimposed on said photographic mate} rial and a half-tone screen arrangedfatlalcertain distance from said negatives, developing, fixing,'washin'g, and finally, drying the jthus"proj duced drop-out; half-tone "and; line positive. f r5'. A -processof producing a drop-Out half tone and line positive comprising the steps of making from an original drawing having highlight, tone and line sections a continuous tone negative, opaquing on said continuous tone neg ative all areas corresponding to the line sections of the original drawing, making from the original drawing a second continuous tone negative, opaquing on said latter continuous tone negative all areas corresponding to the tone sections of the original drawing, making from said original drawing a continuous tone negative, treating said latter continuous tone negative with a subtractive photographic reducer until the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus produced half-tone and line mask negative, bleaching said negative, and intensifying the same consecutively without intermediate photographic fixing, said bleaching and consecutive intensifying being carried out before or after said photographic reducing and fixing of said negative and resulting in increase ofthe opacity of those areas of the negative which correspond to the highlight sections of the original drawing, thereafter superimposing on an unexposed light sensitive photographic material as for instance photo-- graphic film, plate or paper in desired sequence the partly opaque continuous tone negative hav-.

ing opaque areas corresponding to the tone sections of the original drawing, exposing said unexposed photographic material through said superimposed negative, removing said negative, superimposing on said partly exposed photographic material said half-tone and line mask negative developing, fixing, washing, and finallydrying the thus produced drop-out half-tone and line positive. I

16. A process of producing a drop-out half tone positive comprising the steps of making from an original drawing having highlight and tone sections ahalf-tone negative in the usual way, making from the original drawing a continuous tone negative and chemically treating the entire surface of the same in such a manner that the tones in those areas of the negative which correspond to the tone sections of the 'original drawing substantially disappear, fixing the thus produced half-tone mask negative, su-

perimposing said half-tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate or paper, and making a drop-out half-tone positive by exposing said unexposed photographic light sensitive material through said superimposed negatives.

17. A proces of producing a drop-out halftone positive comprising the steps of making from an original drawing having highlight and tone sections a half-tone negative in the usual way, making from the original drawing a continuous tone negative and chemically treating the entire surface of the same in such a manner that the tones in those areas of the negative which correspond to the tone sections of the original drawing substantially disappear, fixing the thus treated negative, bleaching it thereafter, intensifying the thus produced half-tone mask negative without intermediate photographic fixing, thereafter superimposing said half-tone negative and said half-tone mask negative upon an unexposed photographic light sensitive material, e. g., film, plate or paper, exposing said unexposed photographic light sensitive material through said superimposed negatives, developing, fixing, washing, and finally drying the thus produced drop-out half-tone positive.

' ARTHUR L. HUTTKAY.

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