Hi Mike,
Hope this helps
The only medium to dissolve the grainyness of browns is Walnut oil, but it must be art oil, not the kitchen type oil. As a spirit in itself, it is very effective in cleaning brushes, especially reds.
Raw umber is a brown shade, burnt umber is a chocolate ( red ) shade, so depending on what effect I want, depends on which colour I use. Raw umber can make colours very muddy and bland, where as burnt umber can ' lift colours ' and make them ' glow '.
All transparent colours can be made opaque by mixing it with a non transparent colour.
If the base coat ( primer ) is white, then on most applications, I tend to use a matching humbrol first, otherwise you will forever be building up colour layer after layer.This is especially so with reds and blues. On saying this, sap green has a unique property to it. If used over a white base it will firstly only appear as a stain, however if every coat is left to dry, you can get at least 5 darker shades of colour out of it, the final shadow is a mix of sap green and paynes grey. I used this technique on Robin Hood so the final effect remained a pure green.
Nicholas
