US1581012A - Obtaining by alpha single operation alpha correct exposure of plates and culinders comprising half-tones accompanied by test or line drawings for helio engraving - Google Patents

Description

L. l.. PHILIPPE E'r Al.

AprilKls 192e.

'45 In the meth s Patented Apr. y13, 1926.

'UNITED STATES PATENT OFFICE.

.\ LUIEN LON PHILIPPE AND HANS LUGINBUEL, 0F PARIS', FRANCE.

OBTAINING BY A. SINGLE QPEBATION .A CORRECT EXPOSURE OF PLATES AND CY LIN- DERS COMPRIBING HALF-TONES ACCOMPAN IED BY TEXT R LINE DRAWINGS FOR HELIO ENGRAVING.

Application illed Hay 7, v19245. Serial No. 28,728.

To all whom z't may concern:

Be it known that we, LUomN LoN PHILIPPE, a citizen of the French Republic, residing at Rue des Lyonnais, Paris, 5 France, and HANS LUGINBUHL, a citizen of the Swiss Confederation, residing at 8 Rue Boucicaut, Paris, France, have invented certain new and useful improvements for obtaining by a single operation a correct ex- 10 posure of plates and cylinders comprising half tones accompanied by text or line drawings for helio engraving, of 'which the following is a specification.

This invention relates to a heliographic process principally applicable for plates or cylinders comprising photographs in half tone, surrounded wholly or partially by text or by line drawings.A

The object of the process is to enableia simultaneous and correctexposure of the .half tones and the text, assembled together on the same plate, to be obtained at a single operation, in other words to enable, during a single exposure, the text-or the like to be over exposed to any desired extent and in an automatically controllable manner, as compared with the neighbourin half tones.- By the 'use of the process, t ere can be obtained, with very great facility, and without an excessiye expenditurel of time or labour, that is to say with great economy as compared with theknown recesses, a plate or cylinder which is immediately read for etchin `or treatment in the acld/y bat and on w ich there ,can be produced or etched at a single operation all graduations of tintl from intense blacks to absolutely pure whites. j The results obt ined in practice show that all the interm iate tones are v always. produced very clearly and correctly in value without hardness, and that the intense whites of the images can be strongly etched without the riskof engraving the ground orback ound ofthe text. ,l

0F actually employedfor obtaining plates or cylinders by helio engraving, half toneV elements or transparencies and text elements are assembled, and in order to show the features and economy of the.

new process, the usual methods will now be summarized under four principal heads or,

procees each necessitating numerous and long. operatlons. These processes moreover g1ve very irregular or uncertain resulte.

' exposure.

In the usual way, the positive printing elements-for instance on plates with a gelatine and silver bromide coating-are pref pared by regulating the intensity of each transparency by intensifying or reducing, so that a homogeneous whole is produced for The preparatory stages before etching include framing or masking, re-

moval ofthe gelatine by scraping laround the frame to obtain absolute transparency which is necessary for the production of pure whites constitutin the background for the text and preparation of the said text for instance on celluloid film, after which l exposure of the carbon paper takes place, the gelatine film of' which is to be transferred to the metal preparatory to the etchin bath..

met method-The half tones and the textare Vproduced each onwa separate element, Y

then exposed and each engraved separately.

lIn this way two complete operations have to be -gone throu h and it is necessary Ato cover by means o an insoluble varnish the nish or b black paper, during the second ex-v posure. y varying the time of the respective exposures, over exposure. of the text is produced. With this `method the etching treatment of the plate or cylinder is effected asa single operatlon.

Thad mama- The half 'toiles and he text are produced on the same plate and the text is over exposed by covering at a suitable time, masklng for instance by means of black paper, the part occupied by the half d tone photograph. The masks must corre-y spoml yvery exactly to the contour of these photogra hs. The masking may also -be eiected y the use of an opaque varnish.

With these masks however it 1s necessary for the operator to leave a rather considerable gap between the text and the illustration to avoid fogged or veiled portions.

Fou/rtlz. method-The half tones and the text are produced on the same plate, andthe whole exposed during the sameexposure i' period.l Then the portionof the plate or cylinder with the half v tone picture is covered with a soluble varnish, which follows exactly the contour of the picture and which is put on very carefullyas a coating of uniform thickness. The plate or cylinder thus varnished, when perfectly dry, is plunged into the etching bath, which at once attacks the portion not varnished, comprising the text. The Varnish only dissolves at the end of some minutes, then leaving the part comprising the half tones to be attacked. In this way, "a dilerence in the times of .treatment in. the etching bath is obtained, but this last process requires great attention and experience on the part' of a specialcraftsman, to avoid thewhitebackground of the text being attacked in its turn, and especially to obtain correct etching of the picture,

which, nevertheless, is nearly always Without detail in the intermediate tones.

Agccording to the new process, now about to be described, the exposure and the etching treatment of the plate or cylinder can each be effected at one single operation, and in a f very precise manner, giving regular and uniform results. i-

The positive transparencies or the like, in half tone, prepared in the usual manner, are, preferably before drying, uniformly dyed or tinted over ytheir whole surface, by immersion in a bath of dilute colour, preferably roseor yellow.

After drying and 5 scraping' vthe gelatine,

film or` in any other manner, is stuck or iixed in place on the same plate. The whole vis then given a single exposure to the light, whereu on the text becomes over exposed.

40 The di erential duration of e osure canbe regulated once for all,'by the \de ee `ot intensity of the colouring of the hal tone portion. The said colourmg delays the normal to any desired degree. The sin le o eration necessary is therefore slight y to ye or tint the positive printing element to the desired intensity. This' tive 'of our invention, Figs. 1, 2, 3, and 4, are plan views of the textwhich may be printed'on celluloid exposure of the half tone portion lexactly `the half tone image, on a elatine film -formly dyed or stained, an the text printed .newprocess-'possesses a further adth'ehalfrtones, even so as to touch them, without causing, fogged or veiled portions. In `the accompanying drawings, illustra-j a photographic plate under different conditions of treatment.

Fig. 5 is a sectional view showing the different element's of a photographic plate assembled for the last operation, i. e., for exposure of the carbon paper etching film.

In Figs. 1 to 4, the parts covered with points or dots, are those which have a stratum of sensitized gelatine; ,the close oblique hatching lines, indicate, schematically, the image in half tone, with a contour diversified in many ways, while the oblique oppositely directed and spaced hatching lines represent the .coloration of the gelatine stratum (Figs. 2, 3, 4).

The horizontal lines shown in Fi'g. 4, indicate .the text'printed on. Celluloid. As is tobe understood, the positive' of the image is produced from a negative which has not been retouched, cleaned or otherwise treated, and immediately after its production, and without being dried, is wholly immersed in a bath containinA a dilute solution of coloring matterwhictints or dyes the whole stratum, as indicated in Fig. 2 by the spaced, oblique hatching lines.

Afterdrying the dyed positive, the stratum or layer of gelatine is scraped away in tine film showing stains, fogs and undesirable features, are removed so, as to leave the positive plate in the condition indicated by Fig. l3.

The text, printed on this sheet of suitable transparent material, such as celluloid, cellophane, etc., is arranged upon the glass plate around the image as indlcated by the horizontally hatched parts in Fig. 4, the text kbearing sheets being of the same thickness as the gelatine film, so as to present an even surface therewith. i -1 This completes the preparation of the dia-I positive from which the etching sheet is to Y e 1prepared.l

t comprises, upon the one plate of glass,

on transparent sheets, and applied to the clean glass. I

The diapositive being thus complete, reuires no further treatment and may be t en used for the ex osure of the carbon paper etching sheet. ut one such exposure is required, as the tinting of the gelatine bearing the half-tone image prevents over ex osure of the latter.

ig. '5 illustrates the assemblage of the different elements for this exposure, b representing the glass plate, b1 the elatine film having the half tone image or 1 lustration, 0, the celluloid sheet having the text 13 printed thereon, a the carbon paper sheet, with its sensitized gelatine coating a?.

lt may be remarked that as a rule the positive printing elements are dyed or tinted the heliographic process,

before drying, but this is simply to obtain economy in time as compared with drying twice. Obviously. the results would be identical if the elements are dyed or tinted after a previous drying; or they may be treated with an alcoholic solution to favour drying. The restraining or retarding dye or colour may be obtained in any appropriate manner without departing from the principles of the invention. The coating may be of a chemical nature, obtained by dipping, by the use of vapours or it may be of a mechanical nature, obtained by pulvenizing, grinding or powdering the material, and it may be applied after or even before development.

What we claim and desire to secure by Letters Patent of the United States of 1. A photographic diapositive for use in consisting of a glass plate, part of the surface which is coated with a elatine lm bearing a half tone image an with such film, and has attached to it a illustration in half tone,

part of which is uncoated sheet of transparent material having text s graphic plates or cylinders of the type specified, which comprises the Yproduction of a photographic plate of a diapositive of the and without previous drying; the immersion of said diapositive in a dyeing solution; the drying of said.

diapositive; the removal of the gelatine coating from all the parts of the plate surrounding `the illustration; the printing of the text upon a transparent support; the att-aching the latter to the parts of the dia- Eositive from which the gelatine iilm has een removed; the production from saiddiapositive, by a single exposure, of a negative photograph on gelatinized carbon paper; the transfer of the gelatine layer of the carbon-paper to a plate or cylinder and the etching vof the latter.

In witness whereof we aiiix tures.

LUGINBUiiL HANS. PHILIPPE LUCIEN LEON.

our signa-

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