How to get a metalic silver image (Halo-Chrome)

[Nicholas Lindan]

I am looking for a description of the chemistry used to convert a regular photographic print to a silver/chrome image.

"Halo-Chrome" from Rockland Colloid is a commercial product that achieves the same end, but as I have a whole closet full of chemicals I was looking for a mix-it-yourself solution [ha!].

I've tried Googling but I can't seem to find the 'magic search words' that will bring it up.

 

[holmburgers]

Nicholas, I'm curious too so I'm posting to subscribe to the thread.

This effect in the conservation/preservation world is called silver-sulfiding, I believe.

My favorite technique to achieve this is to make a print, wait 60 years, and if I'm lucky, there it is...

 

[eclarke]

Nick, If you have Tim Rudman's book, there's a toning method which paltes out..I'll check it later when I get home..Evan Clarke

 

[holmburgers]

bump. Surely someone can wax on this phenomenon.

I was in a used book store, and in some old photo books there were a couple prints used as bookmarks (undoubtedly from the studio of the photographer whose name was stamped in the inside cover). These prints were horribly sulfided; which actually looked very cool. It was almost as though the print was a polished mirror.

 

[Ian Grant]

I'm about to make a front silvered mirror and the chemistry involved looks promising for this application.

You need to convert the Silver to a halide, a Copper Chloride based bleach is probably the best, then a silver solvent ammonium hydroxde not too strong with additional Sodium Hydroxide, proably in a a suga solution. The idea is to dissolve the silver from the emulsion and it almost immediately plates straight back out in/on the surface of the print. In the Jewellery trade they use stripping solutions to clean up castings despite being Cyanide based the Silver/Gold doesn't remain in the solution.

It's a process that needs looking at in depth.

Ian

 

[holmburgers]

Very interesting Ian.

I've been a little interested in silvering glass ever since I started thinking about color cameras. There's all sorts of stuff you can do with partially silvered mirrors.

In Wall & Jordan's Formulas... there are some silvering instructions; it sounds tricky but doable. So you're saying that effectively these are similar things? Or am I jumping ahead?

 

[Ian Grant]

Yes in many ways the principles the same.

Here's a published formulae, I've NO idea if it works but it does use Ammonia and Hydroxide as I suggested

Silver Mirror Printing, or as Seigel calls it, Specular Silver (SS) Toning

(the “poor person’s daguerreotype”) Issue 3 pp. 28-29, 38, Issue 4 p. 43,
Issue 6 pp. 31-32, Issue 7 pp. 23, 26. Issue 3 is the one you want to buy.


BLEACH
Copper Bleach (CB)
300ml water

10g. sodium chloride (2 ¾ tsp)
10g. copper sulfate (1 ½ tsp)
At time of use, dilute bleach 1+1 water.
(and lots of other formulae)


STEP TWO: REDEVELOPER FORMULAE STOCK SOLUTIONS (mix 1 +10 at time of use)
2 g. hydrazine sulfate
1g hydroxylamine hydrochloride
50ml 25% ammonia
120ml 10% sodium hydroxide
40-200ml distilled water.
(and LOTS of other formulae).

Ian