Hi everybody
I know that these forums are not made to talk about fakes, but I think that some topics could be treated to help collectors without helping counterfeiters. Yesterday I saw a Russian icon, visibly fake and also sold as an imitation, but I was surprised by the riza.
The outer surface of the riza looked finely chased, and just by looking at the inside you could tell that it wasn't made by hand.
I think it was made by electrodeposition, but is a mere guess, since I do not know much about this technique, especially in this type of application.
Is there anyone who can tell where to find more information about this technique and how to recognize a forgery made with this technique?
Thanks
Amena
Electrodeposition
Re: Electrodeposition
There should be any number of books of it, and I know it is often included in more general jewelry making books post 1985. I learned about it a long time ago when in university, when we had to make our own electro-conductive lacquer from finely powdered copper and shellac. Untracht's Concepts and Techniques covered it in one of the early editions. (My copy is at the so I would have to check what edition is is.) .
Re: Electrodeposition
Making An Electrotype
The first step in the production of an electrotype plate consists in the preparation of an impression in wax of the type form. The molding wax usually consists of ozokerite, to which various substances have been added to produce the desired consistency. The molten wax is poured upon one side of a metallic plate or “case,” either lead or copper. After taking the impression of the type form at a slightly elevated temperature by the use of suitable pressure, usually by means of a hydraulic press, the resultant “form” is "trimmed" and “built up” to produce the desired degree of relief in the finished plate.
The form is then coated with graphite, applied either by a wet or a dry process. After washing out the excess of graphite, the form is either introduced directly into the depositing bath, or in some cases is given a preliminary treatment (so-called “oxidizing”) with copper sulphate and iron filings, whereby a thin film of copper is deposited upon the graphite. The baths are usually contained in lead-lined wooden tanks, with copper crossbars, from which the anodes and cathodes are suspended. Electrical connection to the graphited cathode surface is made by means of the suspending hook by either of two methods. In the first, known as the “case connection," the hook is in direct contact with the metallic case, portions of the wax being removed in order to bring the case and the graphite surface in contact, while the back of the case is insulated with wax. In the second method, known as the “face connection,” the hook is in contact with a small copper plate inserted in the wax near the top of the form and in contact with the graphite surface. In the latter method the metallic case itself is not in the circuit, and there is less tendency for copper to deposit upon any accidentally exposed portions of the case.
After the copper is deposited to the desired thickness (usually 0.15 to 0.25 mm., or 0.006 to 0.010 in.) the form is taken from the bath and the copper “shell” is loosened by means of hot water. After trimming, the back of the shell is treated with soldering fluid (usually zinc chloride) and coated with tin foil, after which it is laid face downward upon a heated pan. After the tin foil is melted upon the back of the shells, molten electrotype metal (usually containing from 3 to 4 per cent each of tin and antimony and from 92 to 94 per cent lead) is poured over them The electrotype plates thus produced are cleaned, cut, and trimmed to the desired size and thickness and “finished” to a plane surface, which may be subsequently curved if desired.
Source: The Brass World and Platers Guide - December 1919
Trev.
The first step in the production of an electrotype plate consists in the preparation of an impression in wax of the type form. The molding wax usually consists of ozokerite, to which various substances have been added to produce the desired consistency. The molten wax is poured upon one side of a metallic plate or “case,” either lead or copper. After taking the impression of the type form at a slightly elevated temperature by the use of suitable pressure, usually by means of a hydraulic press, the resultant “form” is "trimmed" and “built up” to produce the desired degree of relief in the finished plate.
The form is then coated with graphite, applied either by a wet or a dry process. After washing out the excess of graphite, the form is either introduced directly into the depositing bath, or in some cases is given a preliminary treatment (so-called “oxidizing”) with copper sulphate and iron filings, whereby a thin film of copper is deposited upon the graphite. The baths are usually contained in lead-lined wooden tanks, with copper crossbars, from which the anodes and cathodes are suspended. Electrical connection to the graphited cathode surface is made by means of the suspending hook by either of two methods. In the first, known as the “case connection," the hook is in direct contact with the metallic case, portions of the wax being removed in order to bring the case and the graphite surface in contact, while the back of the case is insulated with wax. In the second method, known as the “face connection,” the hook is in contact with a small copper plate inserted in the wax near the top of the form and in contact with the graphite surface. In the latter method the metallic case itself is not in the circuit, and there is less tendency for copper to deposit upon any accidentally exposed portions of the case.
After the copper is deposited to the desired thickness (usually 0.15 to 0.25 mm., or 0.006 to 0.010 in.) the form is taken from the bath and the copper “shell” is loosened by means of hot water. After trimming, the back of the shell is treated with soldering fluid (usually zinc chloride) and coated with tin foil, after which it is laid face downward upon a heated pan. After the tin foil is melted upon the back of the shells, molten electrotype metal (usually containing from 3 to 4 per cent each of tin and antimony and from 92 to 94 per cent lead) is poured over them The electrotype plates thus produced are cleaned, cut, and trimmed to the desired size and thickness and “finished” to a plane surface, which may be subsequently curved if desired.
Source: The Brass World and Platers Guide - December 1919
Trev.
Re: Electrodeposition
I continued the investigation and I have some news.
There is actually a company that produces icons with the technique of electrodeposition.
http://www.a-artistico.com/a.artistico/ ... one.html#4
I tried to get details about the processing cycle but I was given only brief information.
They told me they do a "mold" in a special kind of silicone, from which they obtain the riza, which is then hand finished. Sometimes it is made of solid silver, sometimes of copper subsequently silver-plated. The rizas of this company do not have any hallmark that is likely to mislead, but it is clear that a forger could strike these hallmarks later.
At a cursory examination the riza may look handmade,
but at a closer look you can see here and there small bubbles, probably due to defects of the mold.
So be careful
Regards
Amena
There is actually a company that produces icons with the technique of electrodeposition.
http://www.a-artistico.com/a.artistico/ ... one.html#4
I tried to get details about the processing cycle but I was given only brief information.
They told me they do a "mold" in a special kind of silicone, from which they obtain the riza, which is then hand finished. Sometimes it is made of solid silver, sometimes of copper subsequently silver-plated. The rizas of this company do not have any hallmark that is likely to mislead, but it is clear that a forger could strike these hallmarks later.
At a cursory examination the riza may look handmade,
but at a closer look you can see here and there small bubbles, probably due to defects of the mold.
So be careful
Regards
Amena