Lefranc and Bourgeois Liquid mat blue coloured drawing gum for masking  Product that allows you to easily create a masking effect. It can be applied on a white support as well as on a prepared support. Placed on the support before applying colours, this product will prevent the support from absorbing the colour leaving the background colour visible. After a few minutes of drying, it is enough to rub it to make the support appear again. It works with all techniques: gouache, acrylic, watercolour, ink, etc. Its blue opaque colour makes it easier to detect the mask made. Discreet smell Easy application Fast drying in less than 3 minutes Turns blue when dry: easier to detect Easy to remove on the finger It doesn't leave a trace and it doesn't tear out the paper. Brand: Lefranc and Bourgeois