Nitric Acid?

[Benhen]

Hi,

Need help over how to bite into gold leaf and gesso to get that aged look. Mechanical wear is essential but it can look somewhat pretentious on its own.

Does Nitric acid work and if so at what strength. I have been reading about Aqua Regis. But again I know nothing.

Can anyone offer any assistance?

Best wishes,

Ben

[prospero]

Acetone will eat into leaf very quickly. To control it, have a wad of cotton wool dipped in White Spirit
standing by. This will neutralise the Acetone allowing you to control the effect.

Nitric Acid is a bit OTT and is harmful to bare skin.

[JFeig]

There are many tools available to a gilder in aging the surface of a gilded object. Nitric Acid can be very dangerous and uncontrollable in a setting like this. These tools can be either mechanical or applications of other products (waxes, varnishes, paints, glazes, and powders).
Object conservators could, but do not use your proposed method. They rather use layers of assorted materials, dry as well as wet, to achieve an aged finish that matches the original finish.
How have you thought of a method of neutralizing the acid on the unsealed objects surface after such a chemical to the object, and not just the surface.

[vintage frames]

I suppose the first question is - is it real gold?

If it's metal leaf (Dutch Metal) then you can age it with an antiquing fluid. Priory Polishes do one or John Penny. Just dilute it with water first so as to control the action.

If it's real gold you're talking about then nothing will tarnish or age it in by chemical reaction.
The nitric acid you talk about would just dissolve the underlying gesso somewhat. Or maybe that's what you wanted?
I'd imagine you'd have a very sloppy slurry to deal with then copious amounts of water and dilute caustic soda.

Aging gold leaf is a science in itself. There are very few who will help because anything they do know is based on years of trial and error.

A few points-
On oil gilding, use water as your solvent along with a stiff brush or very fine wire wool. Work at right angles to the moulding.
On water gilding, use white spirit and PINK rottenstone.

For a patina, use water based wood stain mixed with some earth pigmented watercolours.
Finish with a layer of RSG.

I hope this helps a bit. There's a lot more behind all that.

[Benhen]

Thank you, Dermot, Jerome and Prospero -- much appreciated.

Perhaps there are no shortcuts. In 'Practical Gilding' by Peter and Ann MacTaggart the only assistance is hidden in a short sentence to coat the areas one wants with shellac then dust rottenstone into the cracks and fissures.

Here's a photo of the sort of effect I was hoping to achieve.

[vintage frames]

The gilding there is oil-gilding on a gesso base.

What you could try is first knock out the edges of the gilding to expose the gesso. Then paint on some hot water which will begin to melt the gesso.
Use a very stiff brush to stipple into the gesso and so get that corroded look.

Don't ever use rottenstone as a finish over gilding.

[Benhen]

Thank you for sharing your hard-won experience, Dermot. Really, thank you.