The Galeria Gloss and Matt Mediums are the everyday workhorses of the Galeria acrylic medium range — straightforward, reliable, and genuinely useful for adjusting the consistency, finish, and handling of acrylic paint without compromising the paint film. Both increase the transparency of colour when mixed on the palette, making them the natural choice for glazing, layering, and any technique where translucency and depth of colour are the priority.
Both mediums share the same core function. Mixed with acrylic colour, they increase transparency and flow, extending the paint while maintaining the integrity of the paint film — unlike water, which when added in excess can break down the binder and compromise the stability of the dried paint. They dry quickly to a flexible, durable finish and are fully compatible with all Galeria Acrylic colours and mediums. The distinction between the two is purely one of finish.
Gloss Medium dries to a high-shine, reflective finish that intensifies colour depth and luminosity. It is the preferred choice for glazing techniques, where thin, transparent layers of colour are built up over a dried base to create depth, richness, and optical colour mixing. The glossy surface between layers also helps subsequent glazes flow smoothly and evenly. It can be mixed with Matt Medium to reduce the sheen to any desired level between the two extremes.
Matt Medium dries to a flat, non-reflective finish that gives colour a more understated, contemporary quality. It is well suited to painters who prefer a chalky, matte surface character, or who want to reduce the natural satin sheen of Galeria Acrylic paint. Like Gloss Medium it increases transparency when mixed with colour, making it equally useful for transparent layering — but with a flatter result on drying.
Both can also be applied to the support before painting to create a more receptive, slightly absorbent ground, or used to seal and protect areas of finished work before applying additional layers.
What is the difference between a painting medium and a varnish? A painting medium is mixed with the paint during the painting process to alter its consistency, transparency, or finish. A varnish is applied as a separate protective layer over the completely finished and dried painting. Galeria Gloss and Matt Mediums are painting mediums — they are not a substitute for a final varnish layer.
What is the difference between Gloss and Matt Medium? Both increase transparency and flow when mixed with acrylic colour. The difference is the finish on drying — Gloss dries to a high-shine reflective surface, Matt dries to a flat non-reflective surface. The two can be mixed in any proportion to achieve any sheen level in between.
How are these different from the Galeria Gloss and Matt Varnishes? The mediums are mixed into the paint during painting to alter transparency and finish. The varnishes are applied over a completely finished and dried painting as a separate protective layer. They are different products for different purposes and should not be used interchangeably.
Can Gloss and Matt Medium be mixed together? Yes — mixing them in different proportions gives complete control over the final sheen level, from fully matt through to fully glossy. This makes a single purchase of both mediums very versatile.
Is adding medium better than adding water? For glazing and transparent work, yes — medium maintains the integrity of the acrylic binder while increasing flow and transparency. Water can be used in moderate amounts but when added in excess it breaks down the binder and weakens the paint film. For most glazing and flow applications, medium gives a more reliable and durable result.
Are they compatible with other Galeria mediums? Yes — all Galeria mediums share the same acrylic binder and are fully intermixable with each other and with Galeria Acrylic paint.
