OPEN Thinner contains no binders and is used to thin the consistency of paint mixes without altering open time, or to maintain and adjust the workability of colors on the palette without the use of water mist and moisturizing palettes.
OPEN Acrylics can be thinned and extended with OPEN Thinner, OPEN Medium, water, or other GOLDEN Mediums. For most painting techniques the following guidelines are recommended:
OPEN Thinner will reduce the viscosity while still preserving the optimal working time. Since OPEN Thinner contains no binders, limit additions to a maximum 3:1 ratio of 3 parts paint to 1 part OPEN Thinner to maintain film integrity. OPEN Medium is useful when a more fluid application is desired while maintaining the working properties and extended open time. Can be added in any ratio.
Water will very rapidly reduce the viscosity of the paint, but will not preserve the extended open time. To maintain film integrity limit additions to a maximum 2:1 ratio of 2 parts paint to 1 part water.
Faster drying GOLDEN Mediums can be added in any ratio to OPEN Acrylics to modify viscosity as well but will lower the open time in proportion to the ratio.
For washes and stains on porous and absorbent grounds, one may exceed the above ratios, although the resulting paint films will become increasingly fragile and water sensitive. To later preserve these works, they will need to be properly framed and protected in ways similar to watercolors, or the surface will need to be consolidated with a layer of acrylic medium or an isolation coat prior to varnishing.