Ceramics
Practical tips for using underglaze pencils and pens to draw fine, durable lines on pottery surfaces.
This evergreen guide offers practical, field-tested techniques for achieving crisp, lasting lines with underglaze pencils and pens on ceramic surfaces, addressing preparation, application, drying, firing, and care.
Published by
Peter Collins
July 26, 2025 - 3 min Read
The craft of drawing with underglaze pencils and pens begins long before contact with clay. Surface preparation matters as much as any stroke you will lay down. Start with a clean, leather-hard piece, free from oils or dust. Lightly abrade the surface to create micro-creases that hold pigment. Establish a baseline by drawing faint guidelines in pencil or with a very fine pen, then build your design in deliberate layers. Choose a graphite-based pencil for initial sketches, but switch to pigment-rich underglaze pens or pencils for final lines. Consistency in pressure yields uniform line weight and predictable results across multiple pieces.
Once your design is sketched, consider the glaze plan behind it. Different underglazes respond to various firing atmospheres, so test your colors on a small sample before committing to a larger piece. A waterproof, heat-stable line often results from using dedicated underglaze technical pens or pencils designed for stoneware. Apply lines with smooth, steady strokes, keeping the nib perpendicular to the surface to avoid wobble. For interior details, use finer nibs; for bold outlines, a slightly thicker mark can complement the glaze without overpowering the form.
Proper drying, glazing, and firing are essential for durable line work.
After sketching, allow the lines to dry fully before applying any glaze layers. Residual moisture can cause runny lines or breakage during firing. When in doubt, let the surface rest for an hour or more in a cool, stable environment. If you notice smudging, gently lift stray pigment with a clean sponge or by carefully dabbing with a dry brush. Always work from larger shapes to small details to prevent accidental smears on finished areas. Drying times vary with humidity, clay body, and line thickness, so observe each piece closely.
Firing dramatically influences line durability. Underglaze lines should be sealed by a compatible transparent glaze to protect from wear. Before applying glaze, ensure your lines are fully dry and scratch-free. Test a scrap piece to confirm that the glaze firing temperature and slope won’t blur or blur too much. Low-fire glazes may soften lines, while high-fire applications can accentuate them. If you’re unsure, consult manufacturer guidelines or a mentor with kiln experience. A well-balanced glaze layer preserves crisp edges and prevents chipping at high contact points.
Color choices and layering strategies improve line durability and readability.
When moving from pencil to pen, maintain cleaner, more deliberate motions. Pens tend to hold their line better under glaze than graphite, which can smudge or blur if moisture migrates during firing. Preserve line integrity by allowing sufficient set time before glazing. If the design includes delicate details, consider reinforcing them with tiny hatch marks or stippling to increase visibility after glaze. Always adjust your technique to the pot’s curvature; convex surfaces demand gentler, slightly lifted strokes to keep lines from looking oversized or distorted.
Color choice matters as much as line quality. Some underglaze palettes appear bold on the surface but lose sharpness after firing. For fine lines, a high-contrast color like cobalt blue, black, or a dense sepia can offer longevity. Test stacking lines of varying hues to evaluate how they interact when fired. If you intend to overlay outlines with a secondary color, ensure the first layer has fully cured to avoid bleeding. To extend durability, seal the lines with a compatible clear glaze that embraces the line rather than dulling it.
Tool maintenance and environmental control extend line durability.
Surface texture can dramatically affect line clarity. Rougher textures catch more pigment, sometimes creating a grainy appearance. In such cases, apply lighter pressure to avoid overloading the surface, and consider a texture-matching technique to keep lines legible. Smoothing the surface with a light burnish before drawing can also reduce stray fibers that lift pigment. Conversely, a matte glaze may soften lines; in this case, reinforce outlines with additional passes or a slightly bolder nib. Observe how different textures interact with your chosen underglaze pencil, adjusting your approach accordingly.
Another key factor is the stability of your drawing tools. Unsuitable nibs or deteriorating leads can cause irregular marks or breakages mid-stroke. Replace worn tips frequently, and store pens upright to prevent nibs from drying out or bending. Some artists prefer ceramic-safe graphite pencils for initial sketches and then switch to micro-needle-tipped pens for emphasis. Keep a dedicated workspace free from dust and drafts, since movement of air can alter drying times and line placement. Regular maintenance of tools prolongs life and keeps lines consistently crisp across production runs.
Practice and observation build a reliable, repeatable process.
Timing your applications around the firing schedule helps preserve line integrity. If you fire after a long glaze-drying period, ensure the surface has no residual dampness. Too much moisture can push pigment beyond desired boundaries, creating blobs that distort the design. Plan your workflow to allow a full interval between drawing and glaze application. During this interval, resist the urge to handle the piece excessively; oils from hands can compromise the surface. A clean, dry environment supports stable lines that maintain their character through the kiln’s peak temperatures.
Practice with repeat pieces to build muscle memory. Repetition teaches you where your pressure should land on curved surfaces and how to keep line weight consistent as the ceramic shape changes. Create a small series devoted to a single motif, varying line density and spacing. Compare outcomes after firing to identify which combinations yield the most reliable results. Maintain a record of tool sets, firing temperatures, glazes, and observed line behavior. Although each piece is unique, patterns emerge that help you predict results and refine technique.
A systematic approach to design and execution reduces guesswork and waste. Begin with a clean concept sketch on paper or a plastic template, then translate it to the clay with precise alignment. Consider using masking tape or slip-trallet guides to maintain symmetry and proportion. As you gain experience, you’ll discover which motifs suit underglaze pencils and pens best, and which compositions benefit from bold outlines versus fine filigree. Resist forcing complex details onto difficult shapes; let the form dictate the line quality. The goal is legible, durable decoration that survives everyday use.
Finally, care and maintenance after finishing are part of longevity. When pots aren’t on display, store them in a dry, stable climate to minimize expansion and contraction stresses. If you notice hairline cracks developing near lines, review the glaze compatibility and firing data to determine if adjustments are required. Regularly inspect your tools for wear, re-ink or replace as needed, and keep a log of successes and failures. With thoughtful preparation, mindful execution, and disciplined firing, underglaze lines remain crisp, durable, and aesthetically enduring for years.
