I will be painting over gold leaf. I’m working with 23.5k gold because I was told this doesn’t tarnish and working on canvas. Is it a good idea to varnish the gold leaf with a varnish like golden archival spray varnish then applying a layer of Gac200 to give the leaf some tooth before starting to paint over in oils? This should help with adhesion. Is there a better method for a more successful result?
We have seen issues with painting oils over both the Archival Varnish and GAC 200 in different testing. The MSA/Archival Varnish can disrupt drying in some oil colors applied over top, leaving them sticky and uncured for an extended period. And the GAC 200 was seen to cause cracking in some lean oil paint applications used in specific thickness over top. We have articles about both of these topics in JustPaint.org. Search the site forRevisiting Oils Over Acrylics andWhy Oil Painting Over MSA or Archival Varnish is not Recommended for more information.
Unfortunately, we have not tested adhesion of oil colors directly over gold leaf. Adhesion may vary depending on the oil application, if there is an alkyd medium added to the paint or if it is used lean or with solvent additions. It would be ideal if your oil application and gold leaf areas could be seperate. With the oil paints butting up against the leaf or just overlapping the edge. Perhaps there are moderators who have experience with oils directly over gold leaf? It seems to be preferable if there doesn’t need layers between the two. Perhaps a test could be done with oil paints directly onto a sacrificial gold leafed surface to determine if the adhesion is acceptable?
Greg Watson
Golden Artist Colors
The history and survival of paint over gold leaf is checkered. This was practice was very common in the early Renaissance where gold was applied, then superimposed with tempera paint and the details were scratched back through the paint to reveal gold lines, etc. This is called sgraffito. As a conservator we often see failure of this paint. Honestly, burnished gold just does not have the mechanical tooth to allow for great paint adhesion. Oil likely will survive better than aqueous paint. We see examples of this in Northern Renaissance are and later in the 19th century.
I am glad that Golden has weighed in on the varnish isolating issue. Greg’s suggestion is sound. In addition to what he stated this practice would also create a solvent sensitive interlayer which could be easily disturbed if the painting ever needed cleaning.
My guess, and it is a guess, that the addition of an alkyd medium to oil that that has not been overly thinned would be the best was to proceed if you want to paint over the gold.