On Monday I was back at the gallery working on the copy of the Vase of Flowers. The day was filled with fine tuning the area around the glass vase and laying in the window reflection, the main highlight in the glass vase.
Typically when I begin the day I will rub a thin layer of linseed oil to re-wet the surface, this makes the new paint meld with the previous layers with a softer effect than painting directly onto a dry canvas.
This Monday I learned that there are times when you want a dry surface to apply paint onto, so I ended up having to wipe down the area of the window reflection where I had at first spread a the linseed oil. A dry spot is particularly important when you are starting off with a pretty wet paint, that is pigment that already has a large quantity of medium mixed into it, because once this wet paint touches the already thin layer of linseed oil the edges spread and start to diffuse. Something that is typcially a good thing but I needed a strong defining edge in this situation.
The first layer of the window reflection was a thinned zinc white with some blue and burnt sienna mixed to take the "whiteness" down some. Zinc white is the most transparent white available.
Later I switched to cremnitz white mixed with medium, it is a more opaque white and has a little more body.