Silver Nitrate Dying

[JOB15]

I decided to try my hand at dyeing scales with Silver Nitrate after reading an old post by the late Neil Miller.
This process was used in the past for dyeing horn scales.

I found myself with a bone scale that had a dark rot through it and in this case the razor was pristine which did not match the rotten scales. That made these scales a good candidate for dyeing.
(My techniques, methods & measurements were created by me)

Vintage Bone Scales



Silver Nitrate


5 Grams Weighed


300ml Water Mixed With The Silver Nitrate


After a 3 Day Soak The Scales Turned a Dark Grey Colour


10 Minutes Under a UV Light



After a Buff The Shine On The Scales Was Outstanding


The Colour Was a Dark Golden Brown

[RezDog]

Nice experiment. Thanks for the information. I am standing by to see where you will take this.

[Brontosaurus]

Interesting project. As I recall, Neil Miller was a photographer as well as a strop-maker. I have used silver nitrate quite a bit with old photographic procedures, and the solution strength as given (~1.5%) strikes me as being on the weak side. It might be interesting to cut the water volume in half (assuming that the scales would be immersed in the resulting solution), to see what the result is, darkening and so forth. If the only exposure to ultraviolet light has been ten minutes under artificial illumination, and no stabilizer has been added afterwards, it may darken further with exposure to natural ultraviolet light. Also, silver-nitrate embedded surfaces darken considerably when exposed to tannins, so you could also experiment with soaking the scales in a very strong solution of tea, or coffee, followed by balsamic vinegar. To bleach the scales, a strong solution of salt water could be used, which acts as reducer and mild stabilizer.

It looks like you used a metal stirring rod. In working with silver nitrate, one should only use glass (preferable) or plastic vessels and tools. Metal will contaminate everything. Distilled water is preferable to tap water so as to avoid contaminants there. Wear nitrile gloves as silver nitrate
stains the skin, and safety goggles to protect the eyes, but I suppose you know this.

Edit. As an afterthought, old accounts of salt-printing speaking of "bronzing," whereby the silver has been reduced completely by an over-exposure to ultraviolet light. I've never worked with bone; but if "bronzing" has been achieved, it might account for the dark, golden effect that you describe. And if so, then it is possible that the result will remain stable. As I recall, weaker silver-nitrate solutions are more light-sensitive than stronger ones, so that would seem to point towards a possible "bronzing." Give the scales a long exposure to natural daylight to know for sure. If there is no change, then such a state probably has been reached. Without protective coats of wax, varnish, etc., exposure to mild alkalis found in shaving soaps may lead to staining or darkening.

[JOB15]

Brontosaurus:
Excellent information thanks. I was a little worried because it is caustic but now i know it is not too caustic.
I have a long way to go with this but it is definitely they way forward.

Shaun:
Today is experiment day for me. I want translucent green horn scales. So let's see what happens.

[RayClem]

If you do this, be sure to wear gloves and old clothing. Silver nitrate will stain your skin as easily as it stains horn scales. When i was in high school chemistry class, we had to work with the chemical. The teacher inspected each of use the following day. If we had any stains on our hands, we failed the experiment for improper lab technique. The stains will go away in time, but it is best to avoid them.

[Brontosaurus]

I want translucent green horn scales. So let's see what happens.

Things look pretty good to me as shown. It's very difficult to get silver to shift to green, the results not being stable. But for blue-green shades, especially if the coloration of the horn would affect things positively, you might try a cyanotype (blue-printing) combined A & B solution, which involves light-sensitive iron instead of silver. Only problem here is that cyanotypes (blueprints) react strongly to alkalis by fading, so the result would have to be protected from direct contact with soap, and possibly even hard water. In the end, dying might be more advantageous.

I'm curious to know of the stability of your experiments as the silver nitrate has not been stabilized (or rendered insensitive to light through the use of hypo) as far as I can follow from your remarks. A blue-printing solution is stabilized very easily with running water.

[JOB15]

Today i placed the scales in direct sunlight.
Leaving for work before sunrise and returning home after sunset i was forced to wait for the weekend.

The scales turned jet black..



Concerning the green, i am looking at using "Verdigris"

[Brontosaurus]

I can't tell from the photo; it looks like a mottled or uneven result. But your description is what I would think would happen, a further darkening because it was only partially exposed. Not sure if it's possible with a weak solution like this, but what could happen is with further exposure, the silver nitrate is fully reduced by the ultraviolet light, releasing silver (known as "bronzing" in the trade), whereby it will lighten slightly with a metallic effect. This could be interesting in itself, but I'm not sure if it would remain stable at that point. (I accidentally bronzed a salt print one time many years ago and seem to recall that the reduced silver still remained on the page even after fixing.)

So, let's say that you liked the tonality as it was in the first set of pics. The way to stabilize it would have been to place in a 2% bath of sodium chloride (table salt) for a couple of minutes to remove the excess silver followed by a 5-10% bath of sodium thiosulfate ("hypo") for around ten minutes to "fix" it, ending with a running water rinse for around 30 mins. The problem here is that both the salt and the hypo would have a bleaching effect, probably lightening it more than you would want.

If the scales are not at the "bronzed" stage, but just jet black like lamp black, placing the scales in a strong salt solution (perhaps even as much as saturated) should bleach them, perhaps even back to where they were after the artificial UV application. The scales would then be nominally stabilized, or rendered not so light sensitive, but a hypo bath would still be needed to really make them no longer light-sensitive (but this shouldn't bleach too much here because the salt had already done the work). In short, in exposing like this, one seeks to over-expose somewhat (or make darker than one's goal) because the stabilizing steps involve bleaching.

[JOB15]

I'm not sure how the last photo looks to you but it is not mottled. Just solid black.
I did expose only one scale to the sunlight. The bronzed metallic scale is really nice but resembles some thing ...metallic and bronzed .It is striking.
I have purchased some sodium thiosulfate and i will follow your stabilizing instructions and tips.

Also today i was boiling horn in Alum water 50g powder in 1ltr water for a few hours. Part of the horn has turned white. I am thinking a longer boil with more Alum, although i need to inspect the pieces tomorrow when they have dried.

I found some old instructions for green horn which involve Alum Boiling / Verdigris(which i must make) & Armagnac . I will follow this recipe.
There are others for Red horn. All interesting stuff..
Cheers
Joseph

[Brontosaurus]

Seems like you are on a good path with the dying procedures too. Good luck.