US992898A - Preparation of surfaces suitable for photo-engraving or photo-etching. - Google Patents

Description

A. PAYNE. PREPARATION 0F SURFAGES SUITABLE POR PHOTO BNGRAVING 0R PHOTO BTGHING. APPLICATION FILED MAE. 5, 1909.

992,898. Patented May 23, 1911.

U ZZ MVM ARTHUR PAYNE,V 0F WHITLEY BAY, EN'GIJAND.

PREPARATION 0F SUBFACES SUITABLE FOR PHOTO-ENGRAVING 0R PHOTO-ETCHING.

Specification of Letters Patent.

Patented Muy 23, 1911.

Application led March 5, 1909. Serial No. 481,292.

To all 'u1/wm 'it may concern:

Be it known that I, -Alrrimn PAYNE, a subject of the King of England, and residing at Whitley Bay, in the county of Northtimberland, in England, have invented certain new and useful Improvements in the Preparation of Surfaces Suitable for Photo- Engraving or- Photo-IJtching, of which the following is a specification.

My invention comprises improvements in and relating to the preparation of surfaces suitable for photo-engraving or photo-etching. and the object is to provide an improved surface or plate of that class which may be placed in the camera and the required image obtained direct upon the surface to be engraved. In prior methods in this art it has been previously proposed to use an emulsion coated upon a flexible support such as metal yfrom which the sensitized film may be separated by an intermediate layer of albumen or some silicate productiw of adhesion merely for the purpose of preventmg the film from blistering; also to use a co per plate covered with a graininflr film or etching ground which is coated with emulsion and finally to use a metal plate coated direct with the emulsion.

According to the present invention I interpose between the metal base and the outer film of sensitized emulsion an intermediate substratum of collodion or other homogeneous substance. this substratum acting to prevent chemical action between said sensitized emulsion and the metal plate and servy ing also as a resist for the` etching fiuid,

which is necessary by the present day rapid methods of etching, for example with a strong spray of acid.

In the accompanying drawings, Figure 1 shows the plate developed with glycerin and immersed iny potassium bichromate and rinsed. Fig. 2 shows the plate developed in hot water. Fig. 3 shows the plate with the resist film removed (as by spirit) and ready for etching as an intaglio plate. Fig. 4 shows the plate with electrolytically deposited metal and the emulsiontilm cleaned off the plate. Fig. 5 shows a plate as shown in Fig. 4 after the resist film has been removed, the plate being now ready for etching.

In above ti res A indicates the metal plate, B the'iesist and insulating film, C the any of the well known methods at present in use. The polished or grained surface of the metal plate is then coated with a. substratum for which purpose I may use a 2 per cent. collodion such as is made by dissolving pyroxylin in a mixture of equal parts of methylated ether .720 and ethyl alcohol .90% and I prefer to slightly color this collodion by the addition of a small quantity of a strong solution of the anilin dye known as brilliant green in ethyl alcohol. I 'do not, however, restrict myself to the use of this particular dye and itis notan essential part of the invention' that any dye should be used for it is only used as a convenience and the plain undycd collodion serves as an efficient substratum. Though I refer to the use of a collodion substratumyet I do not restrict myself to this in particular for other substrata that prevent chemical action between the emulsion and the metal and act as a resist to the etching fluid may be used such as bitumen. gum dammar, celluloid, dragons blood or gum shellac either singly or in cornbination. for instance a more suitable substratum or resist is made by dissolving 3 ozs. gum dammar in 15 fluid ounces of benzol and mixing it with a solution of 150 grains of pyroxylin dissolved in 15 fluid ounces of amy] acetate, this solution being suitably colored with a solution of an anilin dye in alcohol or other suitable solvent. I next proceed to coat the surface to which the substratum has been applied with a very thin film of fine grained gelatine-bromoiodid silver emulsion prepared with aY hard gelatin preferably without the addition of chrome alum or other hardening agent, and if required the emulsion may be made color sensitive by any of the usual methods. This thin film of emulsion must allow the light to penetrate through the film to the substratum so that when the plate is exposed in the camera and afterward devel oped .th'esilver image will have-penetrated 1t into a positive imagcor vice versa, the

right throughI the vvfilm tothe s'ubstratum. Though I specify the kind of emulsion I prefer to use yet I do not limit Amyself to this because emulsions may be used" prepared with other silver haloids or different combinations ofithe' saine or other haloids of 'sil-l with'gelatins ofyarying degrees of ver and hardness,

The abovedescription describes the manner in which the plates are' prepared and theyare used in the following manner. The prepared plate is exposed in the camera in lthe u sual manner eitherwith the use of a half tone screen when'such is required for the production of half tone printingvbloeks, or without the half tone screen when line blocks are being made. It is thenl developed by the timing system of development either with an acid developer such as ferrous oxalate, or an alkaline developer such as glycin. I prefer'to develop the plate for three minglycin developer used at a temperatureof 65 F.

Sodium sulite cryst 1i ounces. Glycin ounce. Potassium carbonate comlzanhyd :2% ounces. Potassium bromid grains. Distilled Water 30 fluid ounces.

\ f But other times of development, other temperatures, .and'differently compounded developers may be used so long as the image f is sufficiently- Vdeveloped that it penetrates thefilm; though for'someispecial applica-Al 'tions of the'inv'ention'this penetration is not always-essential. The plate is then washed with running water for halfa minute. From 'this point onward the'manipulations vary according to the particular work for which the process vis being used.

If the object is to obtain a positive image AAf -from a-negative originalfsuch .as in the l, a .45. making of a positive halftone relief block 'I i' intaglio line or half toneblock is being madef from' a positive original, then afterv the 'from a ,continuous tone negative;l .or van I photographic image is' prepared as s'tated' in' dissolving '4c' l General manipulations it` is fixedby immersing the plate in' a fixing bath (made by ouncesof hypo in 20' fluid ounces of water) for yabout halfa minute which 'is usually'suffi'cient lto' thoroughly x' the thin film of emulsion. The filmin then washed with Water, about -oneminut'es washing usuallyl vbeingy sufficient with running l f water, and the plate 'is then ready for im- '-jmersion in the ghardeningf bichromate so- .501 plate may be sufficiently rinsed with water-7 f plate is again washed withrunnin 1 and then `it is cleared lays-means yof the lThis plate is'then :washedwith water forl about one minute.

upon the plate audit is required to` convert washed negative (or positive) described in., treated for a suitable time, usually half la minute, with a reducer such as the well known reducer made by 'dissolving p manganate of potash`-I 15 grains,l sulfurr acid minims, -distilled water 20 flui ounces, which dissoLvesall the developed silver image out of the film and leaves they? undeveloped silver haloids in the film. The plate is then washed with running water foy I about half a'minute and exposed to daylight o r other suitable actinie light, for a few sa` tive' seconds, and the plate again developet? preferably in daylight or` strong actinic light, with ferrous oxalate developer, or the before mentioned glycin developer, or any of the well known developerswhich do not prepared as u render the gelatin insoluble so aspto prevent subsequent development withk hot water. The plate must be developed with ythe* glycin or other developer until the image is developed right through the film, and three to Ifive minutes is usually sufficient when developing in daylight with the glycin developer Aat a temperature ofy 65 F., but a slightly prolonged development is not harmful. The l water for half a minute and then fixed in the manner alreadydescribed, the plate again being washed with running water u ntil free from hypo, usually for about one minute,

well known hypo and ferricyanid reducer 'or by a Avery weak solution of the before mentioned acidified permanganate yfre ducer, the object of the clearing being to'remove' all traces of thepreviously de- 105 veloped silver that mayhave been left onl those portions'of the image or resist which Will be subsequently dissolved away with hot water; for the presence of any slight `:veil orfogin the clearr portionspf ,110 the image would-harden the gelatinwhendt is immersed iii. the bi'cliromate solution and --preventthe resist being properly developed.

runningv Assuming that a good clear tainedlay"eithervof the. above mentioned.` methodsl as yalready gdes'eribed and that the lines or clearspaees are quite "freefrom fog it is immersed-forthree' minutes ina 120 '5% solution of potassium Abichromate dis sol-ved inlwater vwith or without the addition'fof a sm'allfquantity 1 of potash alum. n This-solution has the well-known'pr'operty i of-Ihardening the gelatin inthe presence of the metallic image, fQ3: other solutions that have a similar catalytic actinfmy'also-'be- "i used for this purpose. The plate is then rinsed with water and developed like a carbon print in hot water of a temperature of General manipulations is about 120 F., first allowing the film to remain in the water for a minute or two and then assisting `the removal of the soluble rtions of the film by agitating the plate 1n the water, or by gently brushing the surface of the film with a soft camel hair brush o1' similar soft material while the film is immersed in the hot water.

When all the soluble gelatin has been removed, the plate is fastened to a whirler such as is used h process workers) and t e surplus water riven off by centrlfugal force, then the plate is dried at a gentle heat by revolving it face downward over a hot plate or a fiat Bunsen burner. The film rapid] dries and when dry is cooled and the co lodion or other substratum removed from those portions of the plate that are not protected by the gelatin reslst b y gently wiplng the surface of the film with a pad of cotton wool moistened with a solvent of the substratum, or by immersing the plate in the solvent and then immediately washing it with water and removing the scum, if neces sary, by gentle rubbing with a pledget of Wet cotton wool. A mixture of equal parts of Meth: ether .TQO-l-ethyl alcohol 90% ma be used for collodion and for celluloi Meth: ether .720 for gum dammar, benzol for bitumen and alcohol for dravons blood and Rgum shellac. When the collodion substratum is used, itis advisable to finally wipe the plate' with la pad of cotton wool moistened with ethyl alcohol after the collodion has been removed with the mixture of ether and alcohol.

- If it is required to convert the negative image into a` positive image or vice versa the prepared plate is immersed into a bath such as is` used in the electro-de osition of metals and a coating of a suitab e metal is deposited either by means of, or without, an electric current, upon the face of the metal plate to be etched, (the particular metal deposited would be one that is not affected by the etching solution used and so protects the metal plate where it is deposited,) the gelatin or substratum resist preventing the metal being deposited except where the metal is exposed. When a suitable thickness of metal resist has been deposited upon the plate, it is removed from the bath and washed, the gelatin and substratum resist being then removed from the plate, leaving the metal resist on the plate. The plate is then etched in the usual manner.

As an example A negative image is prepared upon a zinc plate from a line drawing in such a manner that Vif this plate were placed in the etching bath an intaglio plate would be obtained, but in the preparation of a positiveimage the plate receives a coating of copper by immersing it in a cop er cyanid bath with the prepared surface accurrent through the solution in the usual manner. The gelatin and substratum 'resist is then removed'and the plate etched in an etchingbath of nitric acid of about 5% to 10% strength as usual. Other suitable metals than copper may obviously also be used. The copper is deposited from a hot or cold solution of co per cyanid or such as is usually used for thls purpose, the follow ing solution being a suitable formula:

Water 80 fluid ounces. Soda bisulfite. 1 ounce. Potassium' cyanid 30% 35 ounces. Copper acetate 11 Ammonia .880", #1 fiuid ounce.

Dissolve the bisulfite and cyanid separately in small quantities of the water, place the copper acetate in a mortar and moisten with a little of the water, rub it into a thin aste and add the cyanid solution. Add t e'bisulfite solution to the bulk of water, then add the acetate solution, and lastly add the ammonia. Any of the usual electroplating solutions of copper cyanid may be used 1n lieu of above.

I deposit the silver from a solution of silver cyanid used in the usual manner.

By first etching the metal plate and then electrically' deposlting a metal upon the late before removmgythe resistz metallic p ates may easily befprepared with pictures and designs ininlai metal.

This process may also be used for the production of engraved metallic plates for ornamentation, such as illuminated or memorial brasses, or for ornamental metallic fittings of any description, or for name plates, engraved dials, etc., either in intaglio or relief made in the manner already described, and if required the hollows may be filled in with coloredV wax or other suitable material. y

and adapted for use directly in the camera, 1

consisting in coating a metal late with a homogeneous substratum, app ying to the surface of the latter a film of light-sensitive emulsion compound of metallic haloids and gelatin, the aforesaid substratum being of such a nature as to prevent chemical action between the emulsion film and metallic base, and to act as a resist to etching fluidz exposing the plate in a camera, developing the 65 ing a copper plate and passing an electric image taken, immersing theplate in a solution adapted to harden the emulsion in the In witness whereof I have signed this presence of the metallic image, removing specification in the presence of two wit- 10 'soluble portions of the emulsion, removing nesses. f the substratum from the platel'where not 5- protected :by the emulsion, depositing a l metallic coating upon unprotected parts of Witnesses: l the base and finally removing the remaining CUTHBERT EvnRAT'r,

substratum and emulsion. K I i CHARLES STEPHEN GRDINER.

' ARTHUR PAYNE.

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