|T O P I C R E V I E W
|Posted - May 14 2009 : 4:04:59 PM
Detail of the seal is magnificent! Whoever modified this one was a true master.
|5 L A T E S T R E P L I E S (Newest First)
|Posted - May 14 2009 : 7:53:58 PM
Luiz, I have a camera (FED Leninets) that I suspect was made with the same method. I'll take photos today and post and you tell me if it is. There is a very detailed portait of Lenin engraved on it.
|Posted - May 14 2009 : 7:52:59 PM
The detail is so fine because the logo is not engraved, it is acid-etched into the surface of the brass. So the acid etching process goes something like this:
(1) Polish the surface smooth.
(2) Take a high contrast black and white photo of an image of the seal or logo, in this case, probably from a document or high-quality printing of the USSR Seal. Make a positive transparency of it, actual size needed.
(3) Coat the metal with a photo-resist chemical which can be sprayed or brush-painted onto the metal.
(4) Put the positive transparency on the metal surface which has been coated with the photo-resist and then expose it with ultra-violet light for some specified time, probably about 20 minutes. This exposure hardens the portion of the photo-resist that it shines on.
(5) Wash the photo-resist away ... only the un-exposed areas will wash away because the ultra-violet light will harden the other areas.
(6) Put the piece in acid to etch away a bit of the surface where it is exposed, in this case the areas that would have been black in the original graphic rendition of the Seal and the black areas of the positive transparency.
(7) Wash away the hardened photo-resist that was protecting the areas from the acid.
(8) Lightly buff the surfaces overall.
This is the basic process that was likely used on this camera, so alot of work, yes ... but not hand-engraved.
I believe this camera, and have always thought most other "gold" cameras were just polished down to the brass, but I have never been sure and of course that can only be the case if the part is made of brass to begin with.
I think the way they get the chrome plating on FED and Zorki cameras etc. to be a matte finish is through using an acid bath after the piece is chrome plated. So maybe this camera was made by a former factory worker familiar with acid processes???
Here is a photo of it before I polished it (taken by the seller).
|Posted - May 14 2009 : 7:48:44 PM
It seems to be a photographical etching over the plate. At first the polished surface is treated in a basic solution of electolytic copper plating. after it is emulsified or sentized through nitrate baths followed of bromine. The copper responds to light like silver. A fine wax layer is deposited over the surface. A high contrast drawing is so copied in a strong mercury or sodium vapor lamp which makes the image over the plate. Image is developed. before fixing, a corrosive bath of ferric perclolate does the painstaking etch in the exposed lines. The operation is visually controled. after that, it is completely washed and neutralized. A very thin enamel is now applied which goes into the etched lines by capillarity. Once repolished the ink makes appear all the beautiful drawing.
|Posted - May 14 2009 : 5:35:21 PM
It's a pretty piece alright.
The engraving reminds me of the detail you see in early postage stamps.
Good find, Bill.
|Posted - May 14 2009 : 4:16:20 PM
Wow, really nice engravings. Somebody spent a lot of time to do this... By the way, I don't think that it is polished down to brass, the "gold" Leicas I have look more that they are re-galvanized with brass, the edges look more smooth and the metal feels thicker. I don't know until now how they make it look like brass. Nevertheless it's a nice camera :-)