Mix, Modify, Protect: Mastering Mediums & Varnish

Modern artists have access to an incredible range of mediums and varnishes that can change how paint behaves on your brush and canvas. These versatile additives help you adjust flow, drying time, texture, gloss, and durability — but it’s easy to feel overwhelmed by the shelves of little bottles! This guide breaks down what you really need to know to choose, use, and store them wisely.

Why Use Mediums?

Mediums are additives that mix directly into your paint to alter its properties. They can make paint flow more smoothly, dry slower or faster, become more glossy or matte, or build dramatic texture.

Oil Painting Mediums

Oil painters have long used custom-blended mediums to achieve their signature look. A traditional oil painting medium might combine:

• Damar varnish

• Stand oil

• Turpentine

• A few drops of a drier, like cobalt or Japan drier

Many artists create their own recipes in small glass jars, but pre-made oil mediums are widely available too. Experiment to see what works best for your style.

Helpful Hint: Use the minimum amount needed — straight oil paint forms the strongest, most stable paint film over time.

Acrylic Painting Mediums

Acrylics can be thinned with water, but this can weaken the color and binding. Instead, artists use acrylic mediums to maintain color strength and flexibility while changing flow and texture.

Popular acrylic mediums include:

• Flow Improvers — Thin paint for smooth application

• Gels — Thicken paint for impasto or texture

• Retarders — Slow drying time for blending

• Tinting Mediums — Alter hue or transparency

Watercolor Mediums

Most watercolorists use plain water to dilute paint, but there are useful additives:

• Gum Arabic — Increases brilliance and flow

• Acrylic Mediums — Add body or unique surface effects

• Texture Mediums — Create interesting resist or granulation effects

Varnishes: Protect and Finish Your Paintings

Varnishes are clear solutions of natural or synthetic resins in a solvent. When applied, the solvent evaporates, leaving a protective film that shields your artwork from dirt, dust, and UV rays.

Types of Varnishes for Artists

Picture Varnish

• A final coat that seals and protects a finished painting

• Dries clear and colorless; can be glossy or matte

• Some picture varnishes are removable for future conservation

Retouch Varnish

• A thinner varnish used during the painting process

• Restores the “wet look” when working in layers so colors match properly

• Helps artists judge color more accurately when adding new paint to dried sections

Mixing Varnish

• Varnish (often damar) is sometimes mixed directly into oil paint to thin it for glazing or to add gloss

• Should be used sparingly — it’s more common to add varnish to a medium than to the paint alone

Did You Know?

Many artists’ favorite mediums and varnishes are based on traditional recipes passed down for generations. Look into what your favorite painters use and adapt your own practice over time.

Final Thoughts

You don’t need every bottle in the store — start with a few basic mediums or varnishes for your paint type, read the labels carefully, and experiment with small test pieces to find what works for your unique style.