Why Use Glossy Mediums?

Deciding whether or not a painting needs a glossy finish is up to the individual artist, but surface shine is about much more than just the final, varnished appearance. Using a gloss medium is a great way to access the full range of every color on the palette while getting better control over mixtures and applications at every stage in the process.

A gloss medium keeps colors close to their wet appearance.

Paint often dries a shade or two different from how it was first mixed. In layered techniques, this can make it challenging to achieve accurate mixtures that are consistent from session to session. Even if you work alla prima, using a gloss medium can ensure that the finished, completely dry painting has an appearance that reflects what it looked like fresh on your easel.

Glossy varnish in a medium can help layering in other ways.

In oil painting mediums, resins and varnishes can help paint initially solidify on the surface. Resins can also add tackiness, which promotes adhesion between layers with less beading up. In layered acrylic techniques, adding gloss medium between applications can increase depth and allow light to penetrate and reflect through transparent colors.

Gloss mediums unify surface sheen.

In oil paints, certain colors absorb a lot of vehicle, with a thinner envelope of oil surrounding surface pigment. Even in acrylics, some colors naturally have a more chalky or eggshell surface. Applying these colors unmodified or just thinned with water or solvent can lead to dull spots. Distinctly dull, sunken passages can stand out from the rest of the painting, leaving the overall painting surface looking uneven and inconsistent. This isn’t just an issue of craft, it can be a barrier to viewers’ experience with the artwork, because if the surface calls too much attention to itself, then people have a hard time focusing on the depiction of the subject and colors. Using glossy painting medium imparts the same finish over the whole surface, letting the viewer see the artwork, not just the paint.

Image (left): Portrait of the Actress Luisa Puchol, 1917, by José Pinazo Martínez (Detail, showing sunken and shiny passages)

Gloss medium can increase apparent brightness of colors.

Gloss plays a critical role in making colors achieve maximum brightness. The amount of light that penetrates a paint film impacts how bright the colors appear. A gloss medium can open up paint, separating pigment particles and allowing light to reflect from within, and underneath.

Adding gloss medium is a great way to get off-the-charts darks and brilliant lights.

Glossy dark colors generally have a deeper appearance. The top of a glossy black paint layer is less apparent than a matte finish, revealing the deep, dark color beneath the surface. This effect can give an important advantage when it seems like the limits of your palette are preventing you from reaching the dark colors you need.

A gloss finish can also help keep lighter mixtures looking bright. Adding gloss medium to whites and light tints makes them more resistant to staining when you glaze over top. This allows you to lift or wipe away some of the glaze to restore highlights.

Image (left): Artemisia Gentileschi, “Penitent Magdalene” early 1600s, showing intense darks and brilliant whites kept clean through use of Amber Oil of Venice, a glossy medium

Acrylics and Watercolors

Most oil painting mediums add gloss, but acrylic mediums have a much wider range of matte-finish products. To impart a shiny surface to acrylics, look specifically for products that are described as “gloss finish”.

Gloss can also be important in watercolors, for some of the same reasons. Gum Arabic and Watercolor Medium can be added on the palette to add glossy depth to mixtures.

For some techniques, the amount of vehicle provided in the paint itself is sufficient, but the right medium can help realize maximum color depth and workability. If painting straight from the tube just isn’t getting you where you want to be, experimenting with gloss medium might just open up the range of possibilities your work needs.