Best Underglaze Pens & Brushes for Ceramic Decor 2026
Underglaze pens speed up line work and lettering; brush-on underglaze jars still do the heavy lifting for coverage, layering, and color depth on wheel-thrown and hand-built ware in 2026.
TL;DR
- Speedball Royal Blue Underglaze at $28.87 is the safest all-purpose brush-on pick for underglaze pens and brushes work in 2026 -- Buy.
- Squeeze-tip underglaze pens trade precision for speed and rub off faster during handling than jarred underglaze -- Consider for classroom projects only.
- Speedball White Underglaze at $17.72 is the cheapest jar in the line and doubles as a resist ground under other colors -- Buy.
- A size 0-2 round detail brush handles most fine line work; pens skip the brush question entirely but limit shading control.
- Test every new underglaze color on a spare tile before a finished piece -- kiln setpoints and actual chamber temperature can drift by half a cone.
Underglaze line at a glance
18
Speedball underglaze colors in stock
$17.72
Starting price per jar
$33.04
Top price, Royal Purple
Why this matters
Underglaze is applied before the clear or transparent glaze goes on, which means every brushstroke or pen line is locked in permanently once the piece hits bisque temperature. Pick the wrong tool for the job and you're re-throwing the piece, not touching up a mistake.
Most studios default to whatever brush is closest to the wheel, and most beginners default to whatever pen is on the craft store shelf. Neither decision holds up once you're firing production runs or teaching a classroom of 20 students who all need to finish a piece in one sitting at ProKilnSupply or any other studio supplier.
How this list was built
The ranking below weighs three things: application method fit (line work versus broad coverage), price per jar against the 18-color Speedball line currently stocked, and firing range compatibility, since a color that shifts or burns out between cone 06 and cone 6 wastes a firing cycle. Colors and prices reflect 2026 stock pricing. Pen-style underglazes are covered by category, not by specific brand claim, because coverage and durability vary by manufacturer and aren't something to guess at.
Every item below gets a plain verdict: Buy, Consider, or Skip. No hedging past that.
The ranked list
1. Speedball Royal Blue Underglaze -- the all-purpose workhorse
At $28.87, this is the color most studios reach for first because it holds true from cone 06 through cone 6 without the muddying that cheaper cobalt blends show. It works equally well brushed as a thin wash or built up in two coats for a saturated line. Verdict: Buy.
2. Speedball White Underglaze -- the base coat and resist ground
The lowest-priced jar in the line at $17.72, white underglaze isn't just a color choice -- it's a working layer. Painted under other colors it brightens them; painted as a resist edge it keeps sgraffito lines crisp before you carve back to the clay body. Verdict: Buy.
3. Speedball Flame Red Underglaze -- the color that actually survives the firing
Red and orange underglazes are notorious for burning out or shifting brown past cone 04 in cheaper lines. At $28.87, Flame Red is formulated to fire true across the same cone 06-6 range as the rest of the Speedball set, which is the reason to pay the premium over a generic red. Verdict: Buy.
4. Speedball Leaf Green Underglaze -- the nature-motif pick
Priced at $20.37, this mid-tone green is the one most decorators reach for on botanical and foliage work because it stays stable under a clear glaze without the yellow-green shift some greens show at higher cones. It's a narrower use case than the primaries above. Verdict: Consider.
5. Speedball Royal Purple Underglaze -- the statement color
At $33.04, this is the most expensive jar in the current lineup, and it earns that price with saturation most purples can't hold without turning gray under a glossy glaze. Buy it for showpieces, not for a production run where the cost per piece matters. Verdict: Consider.
6. Speedball Sky Blue and Medium Blue Underglaze -- the shading pair
Both run $17.72 and exist specifically to layer against Royal Blue for gradient work -- lighter values on top, darker values in the recesses. Buying them as a pair rather than individually saves a second order later. Verdict: Buy.
7. Detail brushes -- the tool half of the underglaze pens and brushes equation
The underglaze color only performs as well as the brush applying it. A size 0-2 round handles the bulk of line and detail work that a pen would otherwise be asked to do, and it holds more color per load than a squeeze-tip pen, which means fewer refills mid-piece. The full breakdown of round, liner, and detail brush sizing lives in the detail kits for ceramic artists guide. Verdict: Buy.
8. Squeeze-tip underglaze pens -- the classroom speed pick
Pens exist to solve one problem: getting a group of students or a production line through consistent lettering and outline work fast, without loading a brush between strokes. The tradeoff is coverage -- pens lay down a thinner, more uniform line and don't shade the way a loaded brush does, and that thin line is more prone to rubbing off during handling before the piece is fired. Use them for classroom throughput, not for a piece you're trying to sell at full price. Verdict: Consider.
Underglaze colors in stock
Fires true from cone 06 through cone 6, brush-on application.
$28.87
Holds saturation across cone 06-6 where cheaper reds shift or burn out.
$28.87
Stable mid-tone green for foliage and botanical decoration work.
$20.37
Comparison table
| Pick | Best for | Price | Verdict |
|---|---|---|---|
| Speedball Royal Blue | All-purpose line and wash work | $28.87 | Buy |
| Speedball White | Base coats and resist grounds | $17.72 | Buy |
| Speedball Flame Red | Accent color, cone-stable red | $28.87 | Buy |
| Speedball Leaf Green | Botanical and nature motifs | $20.37 | Consider |
| Speedball Royal Purple | Showpiece color, low run cost | $33.04 | Consider |
| Sky Blue / Medium Blue pair | Shading and gradients | $17.72 each | Buy |
| Detail brushes (size 0-2) | Line work, shading control | Varies | Buy |
| Squeeze-tip underglaze pens | Classroom throughput, lettering | Varies | Consider |
Where to buy
- Buy from an authorized studio retailer that stocks the manufacturer's current formulation -- older stock can behave differently across cone ranges than what's listed on current packaging.
- Check the firing range printed on the jar against your actual clay body cone, not just the bisque cone -- underglaze rated cone 06-6 will not necessarily hold color past cone 6.
- Order color pairs (like the Sky Blue and Medium Blue combination above) together rather than one at a time -- it saves a second freight charge on a qualifying order, and ProKilnSupply ships qualifying orders with free freight.
FAQ
What's the best underglaze for beginners doing brush work?
Speedball Royal Blue Underglaze at $28.87 is the best starting point in 2026 because it fires true across cone 06-6 and forgives uneven brush loading better than thinner colors. Pair it with a size 0-2 round brush for line work and a wider flat for coverage.
Are underglaze pens better than brushes for detail work?
Pens are faster for consistent lines and classroom throughput, but brushes give more control over shading and color depth. Use pens for lettering and outlines, brushes for anything that needs gradient or layered color.
How much does underglaze cost per jar in 2026?
Speedball underglaze jars currently range from $17.72 for colors like White and Sky Blue up to $33.04 for Royal Purple. Price generally tracks pigment cost, so blues and whites run cheaper than purples and burgundies.
Can I mix underglaze colors before applying them?
Yes, underglaze colors can be layered or blended wet-on-wet to create custom shades, the same way the Sky Blue and Medium Blue pair is used for gradient shading. Test any new blend on a tile first since mixed colors can fire differently than either color alone.
Does underglaze need a clear glaze on top?
Most underglaze work gets a clear or transparent glaze over it to protect the surface and add shine, though some artists leave matte underglaze exposed on sculptural or outdoor pieces. Check the specific piece's function before skipping the clear coat.
What cone range do Speedball underglazes fire to?
The Speedball line is formulated to fire consistently from cone 06 through cone 6, covering both low-fire and mid-fire stoneware work. Always confirm your kiln is actually reaching the cone your controller reports before trusting color results.
Why did my underglaze color come out different than the jar?
Color shift usually comes from firing to the wrong cone, applying too thin or too thick a coat, or a kiln running hot or cool relative to its setpoint. Test-fire a tile with the exact application thickness you plan to use before committing a full piece.
One last thing
Color charts on the jar are fired under ideal, evenly-loaded kiln conditions -- your kiln's actual hot spots and cool spots will shift results by a visible margin, especially near elements. Fire a test tile in the same spot on the shelf where the real piece will sit, not just anywhere in the chamber, and keep that tile as a reference for every batch after.