Mix as much as you like into acrylic color/medium to create the viscosity and transparency you want - the more you add, the thinner and more transparent your color will become
Can be thined by diluting with up to 25% water - distilled water will give best results
Stir gently to avoid creating foam - if bubbles appear, leave it to sit while the bubbles rise and disappear
If you're working over a long period of time, mix into color on the palette to keep it fresh and skin-free for longer
This is semi-opaque when wet, transparent when dry