Both brands come in small bottles of either 30 or 48 ml. The bottles now have droppers, which makes application easy. I had bought a small selection of Colorex colors more than five years ago and added two bottles in the meantime. I also have a few ecoline colors - fir green, forest green, siena, warm grey and indigo.
Last week I felt like switching to this medium again. As with all liquid mediums color mixing is not that easy. The Ecoline forest green is a real green green - which in my opinion is a bit too much. But add a drop of warm grey, or siena, or chartreuse and it changes to wonderful quite natural greens!