The difference between underglaze and overglaze is when the color goes on and how hot it is fired. Underglaze is applied to raw clay or bisque and ends up under (or instead of) the glaze. Overglaze is applied on top of a finished, glaze-fired surface and fixed in a low third firing. Regular glaze is a third thing: the glass layer itself, which can be clear or colored.
This comparison is research-based, drawn from maker pages (AMACO, Mayco, Elan Transfers), Orton's cone chart and the Digitalfire ceramic reference. Specs checked October 2026.
Underglaze, glaze and overglaze side by side
| Feature | Underglaze | Glaze | Overglaze |
|---|---|---|---|
| What it is | Clay, a little flux and a lot of stain | Glass formers, flux and clay; clear or colored | China paint, luster, gold or decals with a low-melting flux |
| Applied to | Wet clay, greenware or bisque | Usually bisque | Glaze-fired ware |
| Typical firing | With bisque and glaze firings, cone 06 to 10 by product | Cone 06 to 10 by product | Cone 018 for china paint and lusters (Digitalfire); cone 012 for Elan kiln-fired decals |
| Moves in firing? | Stays put (stiff) | Melts and can run | Fuses to the glaze surface |
| Look on its own | Matte | Gloss, satin or matte | Gloss, metallic or iridescent |
| Extra firing? | No | No (it is the main glaze firing) | Yes, a third firing |
At what stage do you apply underglaze, glaze and overglaze?
Underglaze can go on early. AMACO lists Velvet for wet, leather-hard or bone-dry greenware and for bisque, and Mayco says the same for its Fundamentals line. That early timing is why underglaze suits carving methods such as sgraffito, where you scratch through color to the clay below. The one stage it does not suit is fired glaze, because there is nothing porous left to grip. Whether greenware or bisque is the better choice for your work is covered in how to use underglaze.
Glaze normally goes on bisque, the once-fired pot. Overglaze comes last. Elan Transfers states it plainly for its decals: "Our overglaze decals can only be applied to previously glaze fired pottery." China paints and lusters are the same: they go onto a smooth, already-fired glaze.
Firing temperatures
Underglaze rides along with your normal firings. A Velvet piece might be bisque fired around cone 04, which AMACO gives as 1,945°F (1,063°C), and then glaze fired with a clear at cone 6, 2,232°F (1,222°C) on Orton's chart for self-supporting cones heated at 108°F per hour.
Overglaze needs a separate, much cooler firing so it does not ruin the glaze below. Digitalfire puts china paints, lusters and gold at about cone 018, roughly 1,300 to 1,350°F; Orton lists cone 018 at 1,319°F (715°C). Elan's kiln-fired overglaze decals use a cone 012 schedule that ends at 1,616°F with a 15-minute hold, and its gold decals go to cone 018 or 019. Historic overglaze enamels on porcelain were fired at about 750 to 950°C (1,382 to 1,742°F), according to Wikipedia's summary of the craft.
Our pottery cone chart lists every cone in both scales.
What they are made of
Digitalfire describes underglazes as heavily pigmented mixes of clay, a flux such as feldspar, ceramic stains and a gum to help brushing. Because they hold so much clay and so little glass, they sinter rather than melt, so the color stays where you put it. Our page on what underglaze is goes deeper.
Glaze is mostly glass formers and flux, so it melts and flows. Overglaze colors carry special low-melting fluxes; Digitalfire notes that true low-fire overglazes rely on costly bismuth-based frits and oil-based carriers because they go on non-porous fired surfaces.
Look, feel and color range
Unglazed underglaze is matte; AMACO calls Velvet's surface "velvety smooth." Clear glaze over it deepens the color. Overglaze can give results underglaze cannot: metallic gold, mother-of-pearl lusters and very bright reds, because pigments that would burn out at stoneware temperatures survive a cooler firing. Wikipedia notes that this lower firing is why overglaze historically offered a wider palette than underglaze, which was long limited mostly to cobalt blue.
Durability and food surfaces
Underglaze under a clear glaze is sealed in glass. AMACO gives Velvet a food-safety status only under its LG-10, F-10 or HF-9 clears, and Mayco says Fundamentals are dinnerware safe once a clear glaze is applied. Overglaze sits on top of the glaze, where cutlery and dishwashers can wear it over time. Metallic overglazes such as gold and luster contain metal, so they should not go in a microwave.
Never assume a decorated surface is food safe. Follow each maker's label and directions, fire to the stated cone, and test your own ware. Elan, for example, calls its kiln-fired decals food safe and lead free, but says its oven-fired decals are decorative only.
Underglaze vs glaze: the everyday question
Most home potters are really choosing between underglaze and glaze, not overglaze. Use underglaze for drawn designs, lettering, crisp edges and carved work, because it does not move. Use glaze for the final surface: gloss, satin or matte, and for sealing food surfaces. Many pieces use both, with underglaze designs under a clear coat. Mayco Stroke & Coat blurs the line because it brushes like an underglaze, but Mayco calls it a glaze; see our Stroke & Coat guide. For the basics of applying glaze, read how to glaze pottery.
China paint, lusters and decals: the main overglaze types
China paint
Finely ground colors mixed with an oil medium and painted onto glazed ware, then fired around cone 018. It allows soft shading and layered color through several firings.
Lusters and gold
Metallic and iridescent finishes brushed on thinly over a fired glaze. They need good ventilation while firing, so follow the maker's directions and your kiln's venting guidance.
Overglaze decals
Printed images that slide off backing paper onto glazed ware, then fire at low temperature. Underglaze transfers are different: they go on raw clay or bisque and sit under the glaze. Our underglaze transfers guide explains that route.
A middle route: color on raw glaze
There is a third option that sits between the two. In majolica-style work, potters glaze a pot with an unfired, usually white, glaze and then paint color on top before a single glaze firing. The color sinks into the glaze as it melts, so lines soften slightly but stay in place. AMACO also lists layering Velvet with its Opalescent glazes. This is not overglaze in the strict sense, because there is no extra low firing. Test first, since glaze movement varies by recipe and cone.
The firing order in practice
Seeing the two workflows next to each other makes the difference clear. A typical underglaze piece at home goes like this:
- Throw or build the pot and let it reach leather hard or bone dry.
- Paint underglaze on the greenware (or wait and paint it on bisque).
- Bisque fire, often to cone 04.
- Apply a clear glaze over the design.
- Glaze fire to the clay and glaze's cone, for example cone 6.
An overglaze piece adds a step at the end:
- Make, bisque fire and glaze fire the pot as normal.
- Clean the fired glaze and apply china paint, luster, gold or a decal.
- Run a third, low firing, around cone 018 for china paint and lusters, following the maker's schedule.
Our bisque firing guide explains the first firing in both routes.
Underglaze vs overglaze ceramics in history
The two methods show up clearly in famous wares. Chinese blue and white porcelain is the classic underglaze example: cobalt blue painted on the raw body and sealed under a clear glaze, one of the few colors that survived the high porcelain firing. Japanese kakiemon and Imari wares, and Chinese doucai and wucai, used overglaze enamels to add reds, greens and yellows that could not survive that heat. Many pieces combine both: an underglaze blue outline with overglaze colors added in a later firing.
Cost, equipment and skill
Underglaze needs nothing beyond your normal setup: brushes, a jar of color and the firings you already do. Overglaze needs an extra firing, a kiln controller that can run a low schedule, and materials that cost more per ounce, especially gold and luster. Lusters and china paint mediums also give off fumes as they burn away, so a vented kiln and a ventilated room matter more. Follow the maker's instructions for ventilation and kiln clearance.
Common mistakes
- Painting underglaze on fired glaze and expecting it to stick. It has nothing porous to grab and stays chalky unless refired.
- Firing overglaze too hot. China paint and lusters are made for low firings; a full glaze firing can burn them out.
- Using oven-fired decals on dishes. Elan says its oven-fired decals are decorative only.
- Brushing clear glaze hard over unfired underglaze. It smears designs; dip, spray or sponge the first coat.
Choose underglaze or overglaze
Choose underglaze if you want to paint, draw or carve designs that stay crisp, you want color sealed under a food-safe clear glaze, and you want to avoid an extra firing.
Choose overglaze if you want gold, platinum or luster effects, very bright reds and pinks that will not survive a hot firing, or photographic decals on finished ware, and you are happy to run a third, low firing.
Choose plain glaze if you want an all-over color or surface with no drawn design.
Ready to buy color? Start with our best underglazes guide.
Sources: AMACO Velvet product sheet and LUG page; Mayco 2023 underglaze catalog and Stroke & Coat page; Elan Transfers FAQ and application instructions; Digitalfire glossary entries for underglaze and overglaze; Orton pyrometric cone temperature chart; Wikipedia entries for overglaze decoration and underglaze. Specs checked October 2026.