This matt watercolour varnish from Talens makes the painting less susceptible to moisture. 
 
Dries in a few hours.
Little influence on the degree of gloss.
Does not yellow.
Water resistant when dry, making the painting less susceptible to moisture.
Ready for use, no need to thin.
Apply in one layer and in one direction.
Not suitable for extremely absorbent grounds.
Shake before use.
Clean brushes with white spirit.
Highly flammable.
Composition: colourless, non-yellowing acrylic resin, white spirit, matting agents (silica).