Getting Even Color

The most common problem with underglaze application is uneven coverage: streaky, patchy color that looks amateurish after firing. The fix is almost always technique and patience.

Brushes and Tools

• Flat wash brushes: Best for covering large areas evenly.
• Round detail brushes: For fine lines, dots, and detailed motifs.
• Fan brushes: For blending and soft gradients.
• Sponges: For stamped textures and soft, dappled coverage.

Use soft-bristle brushes designed for ceramics. Stiff brushes leave obvious brush marks that show after firing.

The Three-Coat Rule

One coat of underglaze is almost never enough for solid, opaque color. The clay absorbs the first coat rapidly and the color looks thin and washed out.

Apply three thin coats, letting each coat dry to touch before adding the next. This builds up consistent, opaque coverage.

• Alternate brush stroke direction with each coat (horizontal, then vertical, then diagonal) for the most even result.
• Between coats the surface will look lighter as it dries; this is normal.

Staying Inside the Lines

On greenware, underglaze bleeds slightly into the porous clay surface. To get crisp edges:

• Work quickly and do not overbrush the same area.
• Use a fine round brush with a good tip.
• Clean up edges with a damp brush or damp sponge while still wet.

What Happens in the Kiln

During bisque firing, the binders in the underglaze burn away and the color is locked into the clay. The surface will look slightly matte and dull; this is correct. The final glaze coat, applied after bisque, gives it depth and gloss.

Pro Tip

Test all your underglaze colors on a test tile before committing to a piece. Colors can shift dramatically between the raw state and the final fired result.

Coverage Control Routine

For each color field:

• Coat 1 thin pass
• Dry to touch
• Coat 2 cross-direction pass
• Coat 3 correction pass

Layer discipline prevents streaking and patchy opacity.

Dig Deeper

The brown and amber tones in many underglazes come from manganese dioxide, a compound also used in batteries and industrial chemistry. For a wider view of how colored coatings interact with fired clay, the Wikipedia article on ceramic glaze explains the relationship between underglazes, overglazes, and the glassy surfaces that seal them.