Water gilding is a labour intensive process using valuable materials, that hinges on precise execution. A small slip can undo much of the work in an instant.
Gilding is one of those crafts that is not possible to learn from books or from Youtube. (I tried). I was fortunate to have the opportunity to learn in person from someone at an arts studio that does a lot of gilding. Their teacher is a third generation gilder, and they speak of his abilities with awe. However, he no longer has enough steady work as a gilder, and now works collecting garbage for the city of Florence. Clearly this is another of the crafts in danger of extinction.
Even learning in-person is a tricky business. Those who know how to do it can’t always say how to do it. Anyone who has tried to learn to cook from an experienced chef knows that “Add enough water, not too much, until it’s just right.” Is a refrain. But getting proportions right is vital. Too much water and the gesso cracks. Not enough and its too hard to smooth and you get lumps. Burnish when it’s too wet and the gold lifts up, ruining the piece. Wait until it’s too dry and it becomes hard and it can’t be burnished and won’t take an impression from the tool.
The basic process is:
1. Make rabbit skin glue, filter out lumps
2. Make gesso by filtering chalk into some of the rabbit skin glue
3. Apply size (glue) to a wooden panel.
4. When dry, apply seven coats of gesso onto the wooden panel in one day.
5. Sand or scrape the panel, using charcoal to identify any high or low spots.
6. The next day, make fish glue
7. Mix bolle (a type of red clay) into some of the fish glue. Filter out lumps.
8. Mix water, alcohol, bolle and glue in a dilute mixture and apply to the gessoed panel as a sbolazzatura and allow to dry.
9. Apply four coats of warm bolle/glue to the panel, allowing to dry between coats. Do not allow to overheat or boil.
10. Sand if necessary (it should not be necessary if the temperature/consistency is right)
11. Allow to dry for about 8 hours.
12. Apply gold leaf using water to reactivate the fish glue.
13. Allow to dry a further 8-24 hours
14. Burnish the surface smooth using an agate and a tiny bit of wax
15. Scribe/punch decoration
16. Apply shellac if desired to protect the gold.
All of these steps are calibrated for a northern Italian summer. In a Canadian basement, the temperature is too low and the humidity is too high – in summer. In winter, the humidity is too low. These factors, combined with my lack of experience, inspired me to do some experimentation.
The initial results of my testing are summarized in an Airtable here