Solder resist is the usually green lacquer like coating which covers the major part of most modern circuit boards.  

It is specifically designed to both protect the surface tracks and prevent solder bridges during soldering. The surface often has traces of silicones or similar to promote these properties, which can occasionally lead to strange effects and deformations in the Comp Ref. layer when it is screened on top.

All the types of Solder Resists used as best regarded as permanent and non removable. Although our tests have shown that quite a few of the normal production Resists are lacking strength to resist the new low clean fluxes. we are told that is due to the higher level of solids in the older fluxes, which used to provide some form of protection for Resist.

Although the standard colours are green, red, blue, and black should you be after a unique colour we are always happy to oblige by mixing the resists.  Results are a little unpredictable, but be guaranteed the outcome will be a unique colour!