Gel pens are pens filled with a thick, water-based gel ink that glides across paper and gives bright, opaque lines. They are popular for coloring because they come in lots of colors, including white, glitter and metallic shades that ordinary pens can't match. They also have a few quirks, like slow drying and smudging, that are worth knowing before you buy a set.
This guide covers how gel ink works, what tip size to pick, how to use white and metallic gel pens on dark paper, and when another tool is a better choice for coloring.
A gel pen uses ink that is a mix of water and a thickening agent, with pigment or dye suspended in it. The ink is thicker than the liquid in a rollerball and thinner than the paste in a ballpoint. That thickness is why gel ink looks smooth and bold, and why light colors can show up on dark surfaces.
Two things to know:
- Pigment vs dye. Some gel inks use pigment (tiny solid particles), which tends to be more opaque and lasts longer. Others use dye, which is more transparent. Packaging often says which one is inside. If it doesn't say, test it on a scrap.
- Water resistance varies. Many gel inks are fairly water resistant once dry, but not all. If you plan to add watercolor or a wet marker over the top, test a small mark first.
Gel pens usually come in a few tip sizes. The number is the width of the line in millimeters.
| Tip size | Best for |
|---|
| 0.3 to 0.5 mm (fine) | Outlines, tiny details, writing, thin patterns |
| 0.7 to 0.8 mm (medium) | General coloring of small areas, dots, lettering |
| 1.0 mm and up (bold) | Filling larger spaces, thick lines, highlights |
If you are buying a set for coloring pages, medium is the most useful. If you color very detailed designs like intricate mandalas, a fine tip helps you stay inside the lines.
Standard color gel pens. Bright, simple colors. These are good for detail work and writing on a page.
Pastel gel pens. Soft shades of pink, mint, lilac and the like. They look gentle on white paper and show up better than pastel pencils on darker stock.
Glitter gel pens. Ink with tiny sparkle particles in it. Fun for accents like stars, snowflakes and jewels, though the glitter can make the ink flow a little unevenly.
Metallic gel pens. Gold, silver, bronze and copper shades with a shimmer. They look lovely on dark paper or as accents on a colored page.
White gel pens. A white gel pen is one of the most useful pens in any coloring kit. It adds highlights, snowy details and tiny dots over colors you've already put down.
Neon gel pens. Very bright colors. Best on white paper; they can look dull on dark colors.
This is where gel pens shine. Pencils and most markers vanish on black paper, but opaque gel ink stands out.
- Choose paper that handles it. Smooth, mid-weight paper or cardstock works well. Very thin paper can wrinkle or show ink on the back.
- Start with white or a light metallic. These show up best. Test a color on a corner before you commit.
- Go slow. A fast stroke on dark paper can leave a streaky line. A slower, steady stroke fills in better.
- Layer if you need to. If a line looks faint, let it dry and go over it a second time.
- Wait before touching. Gel ink on dark paper looks wet longer than you expect. Give it a minute or two before you rest your hand on it.
A black page with a mandala drawn in white, silver and gold gel ink is a classic. If you want to try that look, take a print of one of our mandala coloring pages, or use a dark sheet and draw your own pattern with the steps in our mandala drawing guide.
Pros and cons for coloring pages
Gel pens aren't the best tool for every job. Here is an honest look.
- Rich, bold color. Gel ink can look vibrant, with strong solid lines.
- Special colors. White, metallic, glitter and neon colors are hard to get any other way.
- Smooth writing. They glide without much pressure, so they are comfortable for long sessions.
- Great for detail. Fine tips are good for tiny patterns, dots and lettering.
- Good over other media. You can add highlights on top of finished pencil or marker work.
- They can smudge. Many gel inks take a while to dry. Dragging a hand across a fresh line leaves a smear.
- Left handed colorists have it harder. If you write from left to right with your left hand, your hand moves over fresh ink. Try a faster drying pen, work from the right side of the page toward the left, or rest your hand on a scrap sheet of paper.
- Big areas get streaky. Filling a large shape with a gel pen takes time and can leave visible lines. It is better to use pencils or markers for large fills.
- Ink can bleed on thin paper. Check the back of the page. Printer paper is fine for small details, but heavier paper is safer.
- Pens can run out or skip. Gel pens can dry up faster than other kinds, especially with the cap off. Store them flat with the cap on.
- Some colors are less opaque than others. Even gel pens that look bright can turn out thin on dark paper. Test before you color the whole page.
- Test on a scrap first. Every pen behaves a little differently, and every paper does too.
- Do your gel work last. Use pencils or markers for the main color and gel pens for details, highlights and sparkle on top.
- Let it dry. Wait a minute or two between layers.
- Use a scrap sheet under your hand. It keeps the oils from your skin off the page and stops smears.
- Hold the pen at a slight angle. Holding it too upright can cause skipping. A natural writing angle works best.
- Don't press hard. Gel ink flows on its own. Light pressure gives a cleaner line and a longer lasting tip.
- Dots look great. Rows of tiny dots in a contrasting color are an easy way to decorate any coloring page.
- Store them well. Lay pens flat or point down so the ink stays near the tip.
A good mix is to use pencils or markers for the base and gel pens for finishing touches.
- Number of colors. A set of 12 to 24 is enough for most people. Big 100 pen sets are fun but you may never use half of them.
- Variety. Look for a set that includes white, a few metallics and a couple of pastels.
- Refills. Some pens have replaceable ink cartridges, which cut waste. Check the packaging.
- Grip. If you color for a long time, a cushioned grip is easier on the hand.
- Cap or click. Click pens can't be left uncapped by accident, which helps keep the ink from drying out.
Gel pens suit pages with fine details. Try them on mandala coloring pages for tiny dots and highlights, or on flower coloring pages to add shine to petals. For more ideas on how to put different tools together, read our post on coloring techniques.
Yes, for details, highlights and bold accents. For big areas, pencils or markers are usually easier.
Many do while the ink is wet. Give each line a minute to dry and put a scrap sheet under your hand.
Yes. White, metallic and neon gel pens are opaque enough to show on dark paper. Test your colors first.
A medium tip of about 0.7 to 0.8 mm is the most versatile. Pick a fine tip for intricate designs.
Yes. Add gel highlights after the pencil work is finished. Waxy pencil layers can sometimes push the ink away, so test on a corner first.
The tip may be dry or clogged. Scribble on scrap paper, or draw tiny circles. If it still doesn't work, the pen is probably empty.
