Viewing Topic "Preparing oil primed surface for painting"
Abrasive powder or wet-dry sandpaper are good. It is not necessary to abrade a primer, especially Rublev Lead Oil Ground, because it is fairly absorbent.
How do you recommend to sand the surface, with pumice powder or sandpaper? I can get ahold of whole pumice stone (I saw a video, where pumice stone was used to sand glu-chalk gesso), or also pumice powder at Kremer, for example fine grade (0 - 150 µ) or medium grade (0 - 180 µ). However, sandpapers designed for wet sanding also exist. I suppose that the whole thing with moistened rag or felt is only to prevent the dust from swirling around.
Also, is it absolutely necessary to do this treatment? Without it, will the painting be less permanent/the bond between color layer and ground will be weaker?
Last weekend I started a painting on panel which was primed with Rublev lead oil ground approximately 1 year ago. Originally I thought I would use it sooner, but due to various reasons and circumstances it was eventually left untouched for a year. It is only at imprimatura stage now, so I guess I can wipe the color off with rag and turpentine, let it dry and then do the sanding. Should I do this, or can I proceed in painting without worries?
The information about sanding is good, but the latter part about using ammonia is not.
I found this instruction in the book by czech painter and conservator Bohuslav Slánský. The book is from 1953, I think. It is about treatment of dried oil ground before one starts painting:
Shortly before we start our own painting, we sand the surface of the oil ground with a fine pumice powder and a water-soaked and flat-folded linen cloth or a moistened piece of felt. Sanding will remove the impermeable layer of dried oil. The oil binder then penetrates better into the ground, and painting firmly joins with it. It should not be forgotten that lead white is toxic and dust would swirl when grinding with sandpaper. The oxidized surface of the substrate can also be removed in another way: for example, too oily surface of the substrate is lightly wiped with cotton wool moistened with ammonia, which saponifies the dried linoxyn. The remaining traces of saponified linoxyn must then be washed with water.
The book is more than 60 years old, so I wonder, whether this recommendation still reasonable or it is outdated. What do you think?