That didn’t take long! The situation I was trying to simulate is one where the painted leather is kept wet for a period of time. I had this happen at Easter 2009 where we hosted a 17th century tavern that ran for four days. By the end, all the leather drinkware was soaked and the paint was just starting to bleed.
I must admit, early Summer rain in Sydney is somewhat akin to being shot-blasted, but it has accelerated the testing nicely. The oil on modern dye, which had already started to chip, suffered quite badly from this treatment. The gouache on iron black mostly washed off, on the modern dye it stood up a little better and could have been rescued by bring it in earlier and gently drying it. As you would expect, the acrylics are largely unaffected, as is the oil paint on iron black.
Remember, all samples are from the same piece of hide, and all have a coat of varnish and a heavy coat of beeswax over the paint.
Once they’ve dried out, I’ll simulate washing up.