US1928181A - Method of making photographic prints - Google Patents

Description

Sept. 26, 1933. o I l,928,18'1

METHOD OF MAKING PHOTOGRAPHIG PRINTS Filed March 24. 1932 aemh W mmz Patented Sept. 26, 1933 UNITED' STATES METHOD OF MKING' PHOTOGRAPHIC PRINTS Erich Loening, Berlin-Neutempelhof,

. Germany March 24;

in German 9 Claims.

Application r and My invention relates to a method of making photographic prints from printing forms showing illustrations, type matter, or both.

It is an object of my invention to provide a method by which better photographic prints are obtained than heretofore.

To this end, I apply to the background and to the surface of a printing form coloring matter of distinct actinic properties.

For instance, I may apply a non-actinic or less actinic color 'to the background, and an'actinic or more actinic color to the surface of the form, or vice versa.

It has already been proposed to coatthe form throughout with an inactinic layer and to wipe the layer away'from its surface, but it has been found that the contrast between the type or the like at the surface, and the background, is not strong enough, particularly if the form has already been printed from and has lost some of .its brightness at the surface.

As it is diflicult toapply the layer of coloring matter to the form without partly filling'in the interstices between its types or lines, if mechanical means such as a brush or the like, are used, I prefer to spray the color to the form.

In most of the existing printing methods,- and particularly for offset and photogravure printing, a reproduction is first made by book printing, usually on transparent or translucent material, such as the material known as cellophane", thin paper or the like, and the type etc. on this reproduction is made opaque by powdering it with black lead,

bronze powder, or the like. This reproduction is then copied on stone, Zinc, pigment paper, or the like.

The more transparent the bearer, and the more deflned and uniformly opaque the reproduction on the bearer, the better will be the prints from the bearer. a i

However, it is rather dimcult to obtain a clear and uniformly opaque reproduction on such thin material. Particularly if the bearer is perfectly V transparent, such as cellophane or the like, and the print does not readily adhere 'to it, as is the case ifillustrations and type are etched together as in stereotype printing, great care and skill are required. All the same, it is always necessary to treat the reproduction with opaque' powder which results in a perceptibleblurring of contours.

It has been suggested in view of these difliculties nototo print on transparent or translucent material at all, but to make a print on art paper, which is less difficult, to make a photographic neg- 5 ative from the print and a diapositive from the 1932, Serial No. 6oo,993,

y April 1, 1931 negative. This method results in a satisfactory reproduction, with opaque and clearly defined lines, but is obviously rather complicated.

According to my method, all complications are eliminated and in particular it is not necessary to powder the reproduction while at the same time clear denition and uniform opacity are obtained to an extent which was hardly practicable with the existing and much more complicated methods.

Inthe accompanying drawing, the manner in which my method may be performed, is illustrated by way of example.

In the drawing i Figs. 1 and 2 show two methods of coloring the background and the surface of a form in plan,

Fig. 3 is a cross section of a form.

As explained, the surface and the background must be colored in such manner that the actinic properties of the surface are as different as possible from those of the background.

This may be effected in two ways:

(a) The form is coated throughout with a very inactinic color, preferably black or red, and white color is appliedto the surface by a roller;

(b) The form is coated throughout with white, with reflecting aluminium bronze, or with some other very actinic color, and black color is applied to the surface.

case (a) is illustrated in Fig. 1, and case (b) in Fig. 2. It will appear that the type 2 in Fig. 1 and 4 in Fig. 2, is very markedly contrasted with the background of the form l in Fig. 1 and 3 in Fig. 2.

As mentioned, it is difficult to apply the color to the form with a brush or other mechanical means without blurring thin lines by the color entering the interstices 5 and 6 between the types, as shown in Fig.`3. This is entirely eliminated by spraying the color.

C'oating the form with an inactinic layer of varnish or the like, and exposing the type, as mentioned above, is not enough. The contrast obtained in this manner between the surface and the background is not so marked as to yield a clearly defined and uniformly opaque reproduction. Conditions are still less favorable if the type has been used ar'i its surface has become dull, or if lins of brass or etchings in Zinc or copper are in the form. 105

The influence of properties ofthe material is eliminated in my method of double coloring the form, and a uniform and very marked contrast of surface and background is obtained.

has been coated Assumng that the form the known. reflex methods.

- effected by materials throughout with an inactinic color, say black, highly actinic properties are imparted to its surface by applying thereto' a color such as white or silver, etc. In order not to be compelled to employ a color of very high covering properties, the black or other inactinic color may be removed from the surface by a wipercr the like, but this is not indispensable. If the form is coated with an actinic color, such as white, the surface is coated with an inactinic color, such as black.

From the form which has been colored as described, a negative is made on very hard" plates or the like by a camera, or preferably by one of Obviously the negative may be made not only on transparent bearers, such as plates or films, but on bearers of any other material, for instance, paper.

It will be understood that the object of my method is to increase the contrasts of the original, i. e. the form, so that a well-contrasted negative will be obtained. 'It has been found that with the is not dark enough.

In order to obtain full-tone negatives, in which the type or the background, as the case may be, is as opaque as required, the transparent portions of the negative are removed `altogether and a washed-out relievo is obtained. This may be and methods which are old in photography.

such methods are, for instance, as follows:

1. Developing with tanning developers and removing the unexposed portions;

2. Developing with non-tanning developers and removing of the exposed portions with hydrogen peroxide or other agents.

With these methods, particularly for films or glass plates, the unremoved portions of the sensiof the sensitized layer and developed with pyrocatecholwithout sulfite. The non-hardened portions of the condition, are or sodium sulfate and intensified, if required. The result is a positive copy with glassy background and clearly defined opaque type.

reduced by any suitable developer i I claim:

1. The method of making photographic' fulltone prints from printing forms, comprising spraying on to the background, and applying to the surface, of a printing form coloring matter of contrasted actinic properties, and photographing the form.

2. The method of making photographic fulltone prints from letterpress printing forms, comprising spraying the form with inactinic coloring matter throughout, applying to the surface of the form actinic coloring matter, and photographing the form.

3. The method of making photographic fulltone prints from letterpress printing forms; comprising spraying the form with actinic coloring matter throughout, applying to the surface of the form inactinic coloring matter, and photographing the form.

4. The method of making photographic fulltone prints from letterpress printing forms, comprising applying to the background and to the surface of a printing form coloring matter of contrasted actinic-properties, photographing the form, and removing the light portions of the photograph.

5. The method of making photographic fulltone prints from letterpress printing forms, comprising applying to the background and to the surface of a printing form coloring' matter of contrasted actinic properties, photographing the formand forming a relief by removing the parts not exposed to light by dissolving with a nontanning developer.

6. The method of'making photographic fulltone prints from letterpressprinting forms, comprising applying to the background and to the surface of a printing form coloring matter of contrasted actinic properties, photographing the form and forming a relief by developing the negative with non-tanning developers and by dissolving the exposed portions with hydrogen peroxide'. 7. The method of making photographic fulltone prints from letterpress printing forms, comprising applying to the background and to the surface of a printing form coloring matter of contrasted actinic properties, photographing the form and forming a' relief by treating the exposed film with developers and dissolving agents, and making the sensitized layer as opaque as required by repeated developing of the nonremoved portions.

8. The method of making photographic fulltone prints from letterpress printing forms, comprising applying' to the background and to the surface of a printing form coloring matter of contrasted actinic properties, photographing the form and forming a relief by treating the exposed film with developers and dissolving agents. and making the sensitized layer as opaque as required by coloring the nonremoved portions.

9. The method of making photographic fulltone prints from letterpress printing forms, comprising applying to the background and to the surface of a printing form coloring matter of contrasted actinic properties, photographing the form and forming a. relief ,by treating the exposed film with developers and dissolving agents, and making the sensitized layer as opaque as required by intensifying the nonremoved portions,

ERICH LOENING.

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