Today I put on my other hat and did some fire engineering - starting an assessment of fire resistance of some windows.
My Unison pastels arrived about a week ago, and I have put them to use in the current painting. Like all pastels I have tried there is a bit of variability between sticks of different colours. However they do seem to be generally softer that the Winsor and Newton and Rembrandt pastels I have generally been using. About on a par with the Schminke pastels. I'll have to use them a bit more before I decide whether to invest in some more sticks.
I also received the sheets of glassine that I order a while back. The sheets were sent folder rather than rolled, as the postage was cheaper. I covered a painting with a sheet then with a sheet of plywood (an old painting that I'm not that happy with!). There was a small amount of pastel picked up by the glassine where the creases remained where it had been folded, but no obvious damage to the painting. Some other tests showed that it is possible to smudge the pastel if the glassine is rubbed across the surface.
Based on this I have concluded that:
- Glassine is a satisfactory way to cover and protect a pastel painting
- The glassine should be ordered rolled not folded to avoid creases
- The glassine needs to be fixed so that it will not move across the face of the painting.