This is one of my recent watercolour test cards, set up to explore some of the qualities of the four blue watercolour paints in my current collection – Prussian, Ultramarine, Cerulean and Pthalo. All of those swatches at the top were first painted with water and then colour was added; it was perhaps a bit watered down in the Pthalo Blue example, which can be much richer in tone. Once it had dried overnight, I tried lifting out colour in bands. From the top, you have regular paintbrush with water, the same again with clean tissue to blot the section and, most effectively, an old bristle brush. None of them have lifted out perfectly although the scanner makes it look a bit cleaner than the version in front of me.
It is interesting to also compare the other qualities of the colour, like the extremely granulating character of that Ultramarine. Along with the Cerulean, a fair amount can be lifted off while the Prussian and Pthalo are more staining.
Further down, you can see some other experiments. Cerulean and Prussian combined in different ways with Crimson Red Lake. I’ve also put on a bit of Schmincke Neutral Tint. That one is interesting because – perhaps unsurprisingly – you can see that paint lifts out better when you put it onto dry paper (left, square) than wet (right, rectangle – same tests as above).
Another test and a bit more learning. What I need to do now is figure out a clever way to catalogue the results to make them easier to refer back to.