Water and Gouache.

As  I prefer to use the dry brush method when using gouache I like to have 2 jars of water, one to wash the brushes and one (a small one) which I change often. I wet the brush and dab lightly to remove excess water then load the brush with gouache.  I use small amounts from the tube at a time  and reseal the lid promptly to ensure the paint itself  retains its own moisture.  The paint also goes a long way because of the covering strength. I find that the range of colours available lends itself brilliantly to layering.  If you use water with gouache you must wait until the first layer is completely dry before placing another layer over it or the paint will lift and change.    The way I build the colours using very little water means the work dries and I can continue to change the colours and tones as I go.  I know that impasto style work can lead to cracking but if you have the patience, the results of fine layering as opposed to thick paint, can bring great depth to the artwork. 

I have used gouache in the same way as watercolour and the washes are quite lovely.   It has some similar behaviours to watercolour but it is not as transparent.  Obviously the final results are effected by the quality of the paint.

Although there are a number of quality brands of gouache on the market, I prefer to use Daler-Rowney Designers Gouache.  It is a personal preference.  I have become very familiar with the rich colours and versatility.  It also does not appear to fade readily.