Tuesday, July 28, 2020

Moving right along - size gilding and transfer leaf

Yes, it's been almost a year.


I thought I'd get back to writing about the process of learning iconography, Byzantine, Gothic and early Renaissance painting techniques. What the heck. If the world's ending, what do you want to be caught doing? Tweeting? Seriously?

Instead of an interminable post about what I've been doing for the last year, I'm going to assume that most of the readers who come back will have been keeping up on Facebook and elsewhere anyway, so I'll just dive right in where we are now.

Which is here:

It's late July, 4:45 pm GMT+1. The temperature outside is about 38C, and the windows and shutters are closed up to keep at least some of the Italian summer blaze outside. And I've just had some fun unboxing the latest order from Dal Molin.

It's always fun when you get a box of iconography goodies from Dal Molin, the Italian iconography supplier Up Norff. They never did stop working and delivering all through our Covid Crisis. The other day they sent their regular online customers an email saying, as a small family business, they were taking a couple of weeks off, most of August in fact. (This is normal in Italy).

Because I've got three more commissions, and I hope to get going on things immediately, I took the opportunity to order some stuff. Two more books of 23k leaf, a roll of imitation, some Red Oxide pigment and a bottle of oil-based gilder's size. All part of an exciting new adventure in what I think I'm going to call Less Painful Gilding.

I've learned two things in this process: 1) I hate gilding with the white hot passion of a thousand-thousand burning suns, and 2) everybody wants gilding. Gilding is glam. Gilding is Noble. It's Real. It's beautiful and lasting and deeply symbolically meaningful.

First sheet for a project in the spring. 23 3/4 carat. Somewhere between 1/8000 mm to 1/10,000 mm thick. It's so thin you can't touch it with your fingers or it will stick to the microscopic irregularities on your skin. You have to close the windows and turn off any fans. You can't breathe when you lift it (with a special brush made of very fine natural animal hairs) or your breath will twist it over on itself. Then it sticks to itself. Then you have to try to tease it apart using only brushes and get it to lie down flat again. You can't move your hands or arm too quickly close to it because the air movement will pick it up. It's incredibly fiddly to deal with and really a massive pain. But nothing else does what it does.

And doing it has, so far, made me feel like a giant balled fist with clenched teeth. I hate gilding. It makes me want to stab myself in the brain with a chopstick. I was desperate to find some other way of doing it.

So, this is going to seem a bit arcane, but with the new red pigment, Italian Red Oxide, a way opens. In the packet (they send it to you in little plastic zip lock bags) it looked almost identical to the Pozzuoli Rosso I already had. But I mixed them with a bit of water and did a test, and look at the difference. (This pic was taken in bad light with the shutters closed against the afternoon inferno. It's much redder in decent light.)

But the big difference is the grind. It's incredibly fine, as you would expect with a synthetic rather than a ground earth pigment. The Pozz. Ross. gets its colour from exactly the same substance - iron oxide - but because it's an ochre it's a kind of tinted clay, so is very grainy and much less intense - technical term: "saturated" - than the pure iron oxide pigment.

More importantly, the two textures are totally different. And this is because I'm going to use it for gilding. The Pozz. Ross. would have been really unsuitable for what I wanted to do with it, which is to create a coloured ground for gilding. You have to have something coloured underneath the leaf because the gold is so thin the colour of whatever's underneath will show through. So if you put it on a white background it will be dull. Red is best. I've also used yellow ochre, which doesn't give quite the same drama.

But to a two-molecule-thick piece of gold leaf, the graininess of the earth pigment would have been like lying over sandpaper. The little bumps of the ochre grains create little minute shadows which bring down the reflectivity of the whole thing.

Getting an extremely high shine is the point of going to all the extra work when you use bole, sanding, burnishing and polishing it incredibly smooth.

Applying the first layer of bole for an icon of St. Joseph in the spring.

Bole is just fine grain red clay and is the same colour as the red oxide pigment. It stays porous and absorbent, so the leaf will stick to it, while being capable of being polished to a very high shine. Then once you've got the gold down you can burnish it again, mashing the grains into each other with the gold on top and this, in theory, gives you the incredible Russian style mirror-shine.

 ... like this...

(Every time I've burnished gold it either rubs right off or bubbles up and creates holes. Please Lord, no more burnishing.)

 But LAWKS the amount of work you have to do to get there! and the agony of not being able to do it. The least little microscopic flaw in the bole will show through with the gold, and, short of sanding everything off and starting again, you can't fix it. It's incredibly nerve wracking.

This other method with gilding size and red oxide pigment is, reportedly, way simpler. Though you can't get that Russian mirror shine thing - which I could never do anyway.

 You paint the area to be gilded with Red Oxide pigment - no tempera medium, just mixed with distilled water or a little gum arabic watercolour medium. When it's dry, you apply the size, which is just a special chemical adhesive for gold leaf. You paint it on, and wait three hours. It'll be tacky to the touch, but not wet.


Then instead of using the loose leaf gold, you've finally wised up and bought the transfer gold, which you can cut with scissors and lift with the sort of low-friction silicone paper stuff it comes with. So you don't have to use the gilding tip (the long-hair squirrel brush that sometimes picks up a piece of leaf... and sometimes doesn't, as the mood strikes...) you just pick it up with your fingers, lay it down paper side up on the tacky size, rub the paper with your finger so it's good and stuck, peel back the paper and voy-lah! Gilding!

I'm also looking forward to doing more of this technique, which the Italians call "laghetto" - little lake or puddle - and the iconographers call a "float" because the pigment particles are suspended in a very thin solution of egg medium and water, and so float down slowly to settle on the surface of the panel, giving a very pleasing natural mottled effect, which you use as an underpainting.

 Like this:

But you can't use anything grainy, and the more finely ground the pigment the more even the finished result. So, the Red Oxide along with my Ultramarine is going to look very well, I think...