FR2595992A1 - Photoengraving on silvered mirrors - Google Patents

Abstract

The invention relates more especially to the reproduction of photographic prints on silvered mirrors and more generally on any glass substrates having previously been given a metallic coating by the various known methods. The method involves the use of photoengraving to extract the metal film 2 (silvering) chemically deposited on the glass substrate until it has completely disappeared from the places not covered by the positive or negative photo-resist mask 3. The object thus achieved enables facsimiles of all documents and all reproductions for artistic purposes to be faithfully reproduced with the same precision as the original, the duplicate 4 acting as an all-or-nothing filter.

Description

 The present invention relates more particularly to the reproduction of photographic images on silver mirrors and more generally, on all glass substrates, having previously received the metal layer by various known methods.

 The process consists in extracting by photogravure, the metal flow (2) (silvering) deposited on glass substrate (1) by chemical way, until its total disappearance in the places not reserved by the mask in photo-resist (3) pozitive or negative.

 The aim thus achieved allows the faithful reproduction of facsimiles of all documents and all reproductions for artistic purposes, with the same precision as the original; The. counter-type (4) acting as an all-or-nothing filter.

 The prototypes were produced on mirrors, the protective layer of which was previously stripped with solvents from the aromatic canine. which act by dissolving all grease stains, r,; ee, traces of oxides are removed, so that only the purely metallic silver layer remains.

 the silver layer (2) whose thickness is of the order of a few micrometers, receives a controlled atmosphere, a uniform film (3) and which, after heat treatment becomes photo-sonic With ultra-violet nayons. This is obtained by spraying a liquid in an aerosol can, but any other process can be envisaged.

 The nature of the positive or negative photo-sensitive layer depends on the bite used, in order to resist chemical attack and to preserve the old contours formed by a multitude of lines and dots with the greatest possible precision. .

 To preserve the axin.a detail and preserve the quality of the reproduction, it is obvious that the woven or non-woven counter-type is placed on the gelatin side on the photo-sensitive layer to be treated by a rigorous vacuum coating, to avoid diffusion inevitable contours of the mask, in particular, due to the thickness n, even of its substrate which is not negligible.

 In a second order, the choice relating to positive or negative photo-r4sists (3) is different depending on whether they react by destruction or by reinforcement under the action of ultraviolet radiation.

The action of the treatment baths will be decisive and will act by discovering future areas of chemical extraction.

 After the action of the solvent made up by the developer and followed by its ionic neutralization, the reserves (fig. 1 D) remain which protect the argentare from the subsequent chemical attack of the following compounds: iron perclhoride, am persulfate, z, onium, nitric acid, potassium cyanide ...

 The actual etching operation consists in bathing the mirror with the chemical solution constituting the mordant.

The reaction ends at the precise moment when there is no more metal in the previously desired places (fig. 1 E) and thus allows the operator to appreciate the extraction work by the perfect transparency of the original substrate ( glass)
The reserved parts on the rectoconcervoir side the metallized appearance of the original mirror by enhancing its initial reflective properties.

The photo-etching operations being finished, the useful parts (fig. 1 F) which are spared can receive a setallisaticn (7) by polishing baths reinforcing the slopes caused by chemical attack, to contribute to their good mechanical properties and protect the assembly from possible oxidation if the transparency of the glass substrate is desired; (decorations of door panes, windows etc ...)
Likewise, protection by resistant epoxy paint (8) can also contribute to enhancing the reproduction, by its contrast and color: (diploma, etc ...)
Ordinarily, for making mirrors, the metallic silver layer (2) deposited on the glass substrate (1) is very fragile and oxidizes quickly in the ambient environment if none of the protective measures are taken at 1 time.

 In addition, the various mechanical operations which consist of the various manipulations require certain precautions in order to prevent possible risks of scratches or peels.

 To remedy the defects explained above, several consecutive layers of silver have been deposited, to obtain better mechanical strength of the overall deposit thus generated and resist different phases of photo-etching.

 The different baths constituting the logical sequence of photo-etching operations must act quickly under the action of piezo-electric agitators: o-electric (ultrasound).

 The speed of execution of the different phases of development thus carried out is essential and contributes to significantly increasing the quality of the reproductions, on the delicate layer of metallic silver, thereby avoiding the inevitable parasitic reactions due to the products and : employed, if the operations were to extend temporally outside the limits at "-ises.

The present invention will be better understood using the following description, of a preferred but non-limiting embodiment, shown in the accompanying drawings in which
- Figure 1 shows the different phases of the operations of
photo-engraving S
- Figures 2, 3, 4 show the different applications
of this process
- Figure 5 shows the logical extension by extension of the
pre serves process for reproduction by photo-pyro-etching
- Figure 6 shows a variant on different substrates1
other than glass, especially on multilayer metals.

 n Figure 1, the silver layer (2) free of grease and traces of oxides, is covered with a photo-resist film (3) with high resolution extended by vaporization in a thin and uniform layer.

After thermal treatment, the reproduction formed by the counter-type (4) is placed on the gelatin side on the pnoto-resist tick (3) by vacuum plating inside the ultraviolet printer. (5
The photographic transfer is carried out by ultraviolet radiation at source (5) through the counter-type (4) playing the role of mask for a determined time.

The revelation of the photo-resist (3) leaves only the useful particles (fig. 1 D) to reproduce, releasing by dissolution, the parts or fields of action (6) of the bite, which after action constitutes the final phase photo-etching,
In FIG. 2C, a metal layer (7) by deposit, protects the useful silver reserves (2) in order to make them unalterable (cui true), in the case where the transparency of the glass substrate (1) is desired; case of door panes, windows, stained glass ...

 The silver layer (2) can receive a layer of paint (8) over the entire surface, if the transparency of the original substrate is not necessary and ensures the protection of the silver reserves while giving the desired contrast ( reproduction of diplomas ....

 A second mirror (9-10) glued to the reserved side allows a more or less marked relief effect to be obtained, depending on the angle of the observer relative to normal.

 Definition of tirasses by lines and dots (ig. 3) or by screened counter-type (fig. 4) on u-colored glass substrates frosted by the action of fluororyric acid.

flaturely the invention is not limited to the examples of embodiments described, but it also relates to other possibilities of applications which are easy to conceive for those skilled in the art, such as the use of the method according to invention relating more particularly to different substrates, other than glass, in particular on multi-layer metals (FIG. 6) in the simplest case "Zinc-
Steel "where you can depending on the bite used; exploit one layer among others by selective attack with extension to metallic plastics.

An apolication by extension of this process according to ir.vention (fig. 5) to photographic transfer by means of infrared radiation (12) on all substrates (13) such as: p- = piers, cartons, wood. ... by the interposition of the obtained flange; Operating by local burning of their surface
This method advantageously allows photographic transfer, without prior preparation of the surfaces of the receiving substrate, in a
Industrial marking process by photo-pyro-etching.

 As it goes without saying and co:. As a result already from the above, the invention is in no way limited to that of its modes of application, no more than those of the odes of making its various parts, having been more particularly envisaged, it embraces, on the contrary, all the variants.

Claims (10)

 1) Photo-etching process on silvery laughs, characterized in that it consists in chemically extracting the metal film (2) in silver deposited on its glass substrate (1) until it completely disappears (6 ) at the places not reserved by the mask in photo resist (3) positive or negative, the extraction work, consisting of the chemical attack of the mordant, and being finished precisely only insofar as no metal remains in the desired locations (6) beforehand, thereby revealing the perfect transparency of the original glass substrate (1), the parts reserved on the front side retaining the metallic appearance of the original mirror, while retaining its initial reflective properties.  2) A method of photo-etching on silver mirrors, according to claim 1, characterized in that it consists in that the metal layer league in silver (2 d is covered with a resin, in the form of a film in photo-etching (3) sensitive to ultraviolet radiation from the source (5) operating in photographic transfer through the mask formed by the counter-type (4) whose definition is formed by a multitude of lines and dots (fig. 3) or screened (fig. 4) the counter-type operating as an all-or-nothing passive filter.  3) Photo-etching process on silver mirrors, according to claims 1 and 2, characterized in that the glass substrate (1) forming the mirror, receives on one of its faces, one with several consecutive layers of metallic silver ( 2) thus contributing by the thickness of the overall deposit, to better mechanical strength, and to resist without alterations to the various manipulations and to the various treatment baths.  4) Photo-etching process on silver mirrors, according to any one of claims 1, 2 and 3, characterized in that the choice relating to photo-resist (3) in positive or negative resin differ according to whether they react by destruction or by reiforcernnt by the action of ultra-violet radiations thus allowing the determining action of the treatment baths, by acting by discovery of the future domains of extraction by chemical way.  REVS {DICATIONS  5) A method of photo-etching on silver mirrors, according to any one of claims 1, 2, 3 and 4, characterized in that the silver layer (2), following the chemical extraction work, is reinforced by covering a copper deposit (7) with an appropriate bath in the case where the transparency of the glass substrate (1) is desired (fig. 2C), a layer of epoxy paint (8) helps protect the silver reserves while by ensuring the desired artistic effect with the different colors.  6) depoto-etching process on silver mirrors, according to any one of claims 1, 2, 3, 4 and 5, characterized in that the first mirror (1) cbté argentique C 2) receives a second mirror (9 - 10 ) glued to the reserved side, allowing a more or less marked relief effect to be obtained, depending on the angle of the observer relative to normal.  7) A method of photo-etching on silver mirrors, according to any one of claims 1, 2, 3, 4, 5 and 6, characterized in that the present method applies to the various glass substrates (1) can undergo a hydrofluoric acid etching treatment before silvering, ie a color in the bundle at the time of manufacture in order to increase the artistic effect sought.  8) Product obtained by the photo-etching process on silver mirrors, according to any one of claims 1, 2, 3, 4, 5, 6 and 7, characterized in that it can receive a frame in rival maté of any type.  9) Use of the product, obtained by the photo-etching process on silver mirrors, according to any one of claims 1, 2, 3, 4, 5, 6, 7 and 8, characterized in that it consists of a transfer. photographic by means of a source (12) of infrared radiation on all substrates (13) such as: paper, cardboard, wood, by the interposition of the new mask obtained. Infrared radiation passing through the glass substrate at places not reserved by the metallic silver film and thus operating by selective local burning of the irradiated surfaces.  10) Photo-etching process on silver mirrors, according to all of the preceding claims 1, 2, 3, 4, 5, 6, 7, s and 9, characterized in that the present process also applies to different substrates other than glass, in the example of multilayer metals (fig. 6), where, depending on the mordant used, one layer among others can be exploited by selective attack.