Tarnishing silver leaf gilding

[framemaker]

I was wondering if any of the hand finishers/gilders on the forum had ever used chemicals such as hydrogen or sodium sulphide to treat silver leaf to give it an oxidised/tarnished appearance. I have some of these chemicals but am unsure how to mix and apply them, and also does the chemical reaction need to be neutralised somehow before the leaf is sealed?!

I am all for just having a go and seeing what happens but if anyone has done this before some tips would be appreciated. I want to try and achieve a uniformed pewter colour to the leaf, basically how it goes when left to tarnish naturally.

Thanks for any advice
Richard

[prospero]

Never done it myself, but I have heard of the use of Indian Ink (heavily diluted) dabbed on with a rag. I've used Black French Polish in a similar fashion on gold leaf.

Try a scrap bit first.

[JFeig]

Yes- you can use assorted oxidizers using various strengths and methods of application ( brush - sponge - splatter - drip - spray - etc). each method gives a different pattern. I would suggest rinsing with several applications of purified water before sealing. The assorted methods and concentrations is what makes it and"art" vs a mechanical surface treatment. Different oxidizers also give slightly different colors to the silver leaf.

[Not your average framer]

Liberon produce various patinating fluids. It might be worth phoning their help line to see if they can offer any advice.

If I remember this right, I think household bleach or ammonia will form a dark oxide on silver. If so you might need to experiment to find the correct concetration in water to get the right amount of darkening.

There is also a chemical which some members of the antique trade buy from photographic suppliers to produce the same effect. Of course very few will admit to knowing anything about it! Unfortunately a good friend in that trade who could have told me what it is, passed away earlier in the year.

A final thought - I think I am right in saying that the artist's colour "Mars black" should be a transparent pigment, (if it is the genuine thing) and therefore could be thinned before applying to acheive the desired effect. Opaque colours can also be used, but tend to give a rather dull and lifeless effect.

[Roboframer]

I use gold leaf quite a bit - mainly for calligraphy but also for mount decoration. I've never gilded a frame, bar the odd sight edge.

Because silver tarnishes I use white gold leaf instead, there is also platinum leaf but I've never used that - don't see the point!

But because real silver leaf DOES tarnish naturally, would it maybe be better to oxidise white gold leaf? Otherwise the silver leaf would tarnish naturally and you'd lose your effect? Or would sealing prevent that?

I get my stuff from W Habberley Meadows in Birmingham - one of only two gold beaters in the UK (according to them) the other one is in Cheshire - they (WHM) do a 'moon gold' which is wonderful.

I'd love a guided tour of their place - to follow on from one I've already had from the UK's only vellum/parchment manufacturer in Newport Pagnell - William Cowley.

[Not your average framer]

O.K., I've been checking up on what I thought I remembered.

Household bleach will darken and tarnish silver, wich is as I thought.

However ammonia has the opposite effect and will remove the tarnishing, but prolonged reaction between ammonia and silver is not a good idea as it can create fulminates which can be very unstable and highly explosive.

[framejunkie]

... prolonged reaction between ammonia and silver is not a good idea as it can create fulminates which can be very unstable and highly explosive.

I'd have thought Robo would have known that - he does a lot of fulminating

[Roboframer]

Fulminating - "Coming on suddenly with great severity."

Yeah, but just once a month!

[framemaker]

Thanks for all the replies and ideas
I gilded three samples last night so I will try applying some different patinations some time today and post some photos of what happens (as long as they don't go disastrously wrong!), I made a mistake in my original posting, I don't have hydrogen sulphide which is severely toxic it is potassium sulphide I have which is only moderately toxic. There is definitely a lot of different things to experiment with to add different effects to the leaf.

Liberon produce various patinating fluids. It might be worth phoning their help line to see if they can offer any advice.

If I remember this right, I think household bleach or ammonia will form a dark oxide on silver. If so you might need to experiment to find the correct concentration in water to get the right amount of darkening.

Thanks NYAF, I have ordered some of Liberons cold patination treatments for metal, I have also heard of using ammonia and also remember reading somewhere that vinegar could be used to add patina to silver...

I use gold leaf quite a bit - mainly for calligraphy but also for mount decoration. I've never gilded a frame, bar the odd sight edge.

Because silver tarnishes I use white gold leaf instead, there is also platinum leaf but I've never used that - don't see the point!

But because real silver leaf DOES tarnish naturally, would it maybe be better to oxidise white gold leaf? Otherwise the silver leaf would tarnish naturally and you'd lose your effect? Or would sealing prevent that?

I'd love a guided tour of their place - to follow on from one I've already had from the UK's only vellum/parchment manufacturer in Newport Pagnell - William Cowley.

Roboframer, a tour of Habberley Meadows would be great! I also use them for leaf, and use a fair bit of the 12ct white gold (and the moon, what a great colour!)
Once I get the silver leaf the tarnished colour I am looking for I would then seal it to stop the colour changing over time naturally, that is why I was wondering if the chemical process that I apply would need to be stopped or neutralised (thanks JFeig for suggesting rinsing with purified water) somehow before the surface is sealed.

I have never used platinum but have used palladium, I think these are the only two white metals that will not tarnish at all, but they are very expensive. Because white gold is 50:50 gold and silver it will start to change colour and tarnish eventually, although not as easily as pure silver, so when I use it I always apply some renaissance wax to slow this process down.

Will post some photos of the results soon, thanks again for the tips.

[framemaker]

Here are some photos of my experiments with chemical patination on silver gilding
first one is sodium sulphide, far too strong mix has had quite a dramatic effect on the silver, similar to the varigated dutch metal leaf you can get.
second photo is potassium sulphide, again its too strong and has caused severe tarnishing.
third image is a weak PS solution with some red oxide pigment.
fourth is a weak PS, I am quite pleased with this one, its the closest so far to the effect I want to get, the subtle colours on the leaf are lost in the photo.
fifth image is again weak PS with some pigments, again this looks much better in the flesh, honest.

I have still not managed to get the colour I want, but I think I will get it right in the end.

[prospero]

Coool.

I can't say I find any of them unpleasant. They would all look good on the right picture. The top one is a bit OTT, but maybe on a domed or reverse moulding....

I agree the fourth one is the most appealing.

Thanks for posting the piccies.

[Not your average framer]

Thanks for the pics. They are very informative. I think there's some useful lessons to be learnt here. Please keep us all informed.

[gesso]

Nice experiments. I think gassing or sawdust the silver is a better way to achieve the effects your looking for. I have a number ofgilded chevron samples that have been with me for over 14 years and it is suprising from the same initial finish just how many variants that have manifested in that time. There are so many factors that have contributed to the variations, location, base woods, handleing and even those burnished or not. When customers come in and look at the samples I always piont out that my gilded frames like wine , get better as they grow older!

There is a book on the patination of metals ....but silver is not widely covered. I got mine from Tirantys(?) in London. Ill post up the isbn later mind its about £40 but makes a great xmas day read

here you go:
http://www.tiranti.co.uk/product.asp?Co ... Product=35

[Benhen]

Brilliant posts.
I saw a Lowry at the Lowry in Manchester in a very subtle patinated frame. In a way your first photo may have been the route to achieving what looked so good in the museum. But in that case, I guess, it was a thin profile moulding where perhaps the process was less fierce and or a lot of the leaf was rubbed off and plenty of soft wax applied.
What is P5, please?

[Jamesnkr]

Potassium Sulphide is what Richard refers to; it's an S not a 5.

[Benhen]

Thanks, James. Ever helpful.
Here is the example at the Lowry. Utterly beautiful, like gun metal. Doesn’t show in the photo. But, you know, one risks life and limb running photograph prohibition at museums.

[louisesimon]

Once the desired effect has been achieved, how do you stop it going further? Do you wash it down then seal it as normal? Or will it tarnish to a certain level then stop tarnishing anymore?

[Not your average framer]

I'm probably mistaken, but are these substances connected to chemicals fertilizers. I can't find out much about this, but I keep thinking that I've heard something about these substances somewhere. As these substances are commercially available, what they used for? There's got to be morel info somewhere.

My father was a chemist and when he was alive, he mentioned sulfur candles and that they were used for furmigating buildings. Well, I was wondering what compound is produced by burning these. As far as I'm aware sulfur is normally solid in form, so in gaseous form is this a compound capable of oxiding silver. I don't know, just wondering.

[Jamesnkr]

You are probably thinking of Potassium Sulphate - K2SO4 - which is a fertiliser. Potassium Sulphide, K2S, is the chemical in question. Sulphur oxidises silver, which is why you should never eat eggs with silver cutlery (it makes them taste funny too). Eggs of course have sulphur in them, (two of the amino acids in the egg white contain sulphur) hence the Hydrogen Sulphide smell of bad eggs as the amino acids break down - or go bad.

Potassium Sulphide can be bought as a white powder. Mix it with water - the internet suggests 5 parts water to 1 part Potassium Sulphide - and then paint it on to your silver. You can also use flowers of sulphur - brimstone - in water to achieve a similar effect, but it doesn't really dissolve in water and it's a slower process.

For sale here.

https://www.sigmaaldrich.com/catalog/se ... us=product

https://www.bettsmetalsales.com/p-Potas ... hide-100g/

[Not your average framer]

Thanks for educating me. I've learnt something new today!