Quick answer: To use watercolor paint tubes, squeeze a pea-sized amount of each color into a palette well, then pick up pigment with a wet brush and mix it with water on the palette until you reach the transparency you want. You can paint directly from the fresh paste for intense color, or let the squeezed paint dry in the wells and reactivate it with water later, exactly like pan watercolors. Tubes are best for large washes, strong darks, and mixing big batches; dried tube paint in a palette is best for travel and quick sketches.
A tube of watercolor confuses a lot of beginners because it looks like acrylic or gouache: thick, opaque, and nothing like the pale washes they expect. The paste in the tube is concentrated pigment and binder. It only becomes watercolor once you add water, and how much water you add is the entire craft.
This guide explains how to use watercolor paint tubes from the first squeeze to a dried, reusable palette: how much to put out, how to dilute to different strengths, when fresh paste beats dried paint, how to store tubes so they do not harden, and how to open the ones that already have. If you find yourself losing caps and brushes in a cluttered drawer, the roundup of the best paintbrush tubes and holders for painters covers organizers that keep both within reach.
What Is Actually in a Watercolor Tube
Tube watercolor is pigment ground into a binder of gum arabic (a tree sap), with glycerin or honey added to keep the paste from drying rock-hard, and a wetting agent so it disperses in water. Pan watercolors are the same recipe with less humectant, poured and dried into cakes.
That shared recipe is why tube paint can be dried in a palette and used like a pan. It is also why the paste is so concentrated: a 5 ml tube holds enough pigment for dozens of paintings when properly diluted.
Tubes come mainly in 5 ml, 14 or 15 ml, and 37 ml sizes. Beginners usually do better with several 5 ml tubes of good paint than one large tube each of a few colors. Watercolor goes a long way.
Tubes vs Pans: When Each Makes Sense
| Tube watercolor | Pan watercolor | |
|---|---|---|
| Picking up pigment | Instant, from soft paste | Needs scrubbing or pre-wetting |
| Large washes | Easy to mix big puddles | Slow to lift enough pigment |
| Dark, saturated passages | Excellent | Harder to reach full strength |
| Travel and sketching | Bulky unless pre-dried in a palette | Compact and ready |
| Waste | Easy to squeeze out too much | Almost none |
| Cost per painting | Lower in large sizes | Higher per gram |
| Brush wear | Gentle | Scrubbing hard pans wears tips |
Most working watercolorists use both approaches: tubes for the studio, and a palette of dried tube paint for the field. You do not have to choose.
How to Use Watercolor Paint Tubes: Step by Step
Step 1: Set up a palette with wells
You need a surface with separate wells for paint and a flat area for mixing. A plastic or ceramic palette, an enamel butcher tray, or a white dinner plate all work. Avoid porous surfaces like cardboard. White is important so you can judge the mixed color against what it will look like on paper.
Step 2: Squeeze out a small amount
A blob the size of a pea, roughly 1/4 inch across, is plenty for a sketch-sized painting. For a large wash on a full sheet, squeeze out more, but it is easier to add than to waste. Put each color in its own well and leave space between them so wet colors do not run together.
Squeeze from the bottom of the tube and roll it up as you go. Wipe the threads before recapping.
Step 3: Wet your brush and pick up pigment
Dip the brush in clean water, then touch it to the edge of the paint blob rather than stabbing into the center. A little paste on the brush goes a long way. Transfer that to the mixing area.
Step 4: Dilute to the strength you want
This is the heart of watercolor. The same pigment gives completely different results at different water ratios. Watercolorists often describe strength in food terms:
- Tea: lots of water, a hint of pigment. Pale skies, first washes, distant hills. Roughly 10 parts water to 1 part paint.
- Coffee: medium strength. Mid-tone shapes, local color. Around 4 or 5 to 1.
- Milk: creamy and translucent. Shadows, foreground color. About 2 to 1.
- Butter: nearly straight from the tube with just enough water to flow. Darkest darks, calligraphic marks.
Test every mix on a scrap of the same paper before it goes on the painting. Watercolor dries 20 to 30 percent lighter than it looks wet, so mix a little stronger than the final value you want.
Step 5: Mix colors on the palette
Pull a little of a second color into your puddle and stir with the brush. Mix enough for the whole passage so you do not run out halfway through a wash. For a clean mix, limit yourself to two or three pigments; more than that tends toward mud.
Step 6: Paint, and keep the puddle alive
Load the brush fully and lay the color down. For a smooth wash, tilt the paper slightly, work from top to bottom, and keep a bead of wet paint at the leading edge. Reload from the same puddle so the value stays consistent.
Step 7: Let leftover paint dry in the wells
Do not wash the palette at the end. Let the paint dry where it sits. Tomorrow, a wet brush brings it right back. This is the single biggest money-saver in watercolor and it is why tube paint rarely goes to waste.
Fresh From the Tube vs Dried in the Palette
Fresh paste releases pigment instantly and gives the most saturated color. It is the best choice for dark accents, bold mixes, and granulating pigments that look best with heavy pigment loads.
Dried paint in a well is slower to release but perfectly usable. Spritz the palette with water two or three minutes before painting to soften the cakes. Dried paint is ideal for travel palettes, quick sketches, and anyone who wants to stop squeezing out paint every session.
A few pigments behave differently once dried. Some earth colors and a few modern organics can dry harder than others and take extra wetting. Colors with a lot of honey in the formula stay slightly tacky and can run together in a tilted palette. None of this ruins the paint; it is just something to notice with your particular brand.
Building a Travel Palette From Tubes
- Choose an empty metal tin or plastic palette with removable half pans or fixed wells.
- Squeeze each color into its pan until it is about two-thirds full. Overfilled pans crack as they shrink.
- Tap the pan on the table to level the paint and release air bubbles.
- Let it dry uncovered for two to three days. The surface will dimple and shrink; top it up once if you want a full pan.
- Label each pan with the pigment name on a piece of tape underneath. Dried colors can look alike.
- Keep the tube. A refilled pan costs a fraction of a new one.
How Much Water Is Too Much?
Beginners usually err in one direction: too little water, which produces streaky, chalky, or opaque passages that look like gouache. Watercolor should be transparent enough to see the white of the paper through it in all but the darkest areas.
The opposite problem, too much water, shows up as blooms (uneven backruns where a wet area dried into a damp one), pigment pooling at the edges, and buckled paper. The fix is to blot the brush on a towel before touching the paper, and to use heavier paper (140 lb or more) that can take the moisture.
A useful habit: after loading the brush, touch the heel of the brush to a paper towel for a half second. That removes the excess that causes drips without starving the stroke.
How to Hold a Paintbrush for Watercolor
Tube paint and a loaded brush give you control that pans do not, but only if the grip allows it.
- Near the ferrule, like a pencil: maximum control for details and edges. Use with milk or butter consistency.
- Midway up the handle: looser strokes, good for mid-size shapes and foliage.
- At the end of the handle: the brush barely touches down and strokes become expressive and uneven. Good for loose washes and tea-strength skies.
Keep the wrist relaxed and move from the elbow for long strokes. A tight grip near the tip makes washes choppy.
Caring for the Tubes Themselves
Watercolor tubes last for years if you handle them well, and fail in two predictable ways if you do not.
Preventing hard tubes
Tube watercolor hardens when the cap is left loose and moisture evaporates, or when a smear of paint on the threads glues the cap and it is never fully closed again. Wipe the threads with a damp cloth before recapping, cap snugly, and store tubes cap-up in a box or organizer so they do not get crushed.
Reviving dried tube paint
Hardened watercolor is not ruined, because the binder redissolves in water. Cut the tube open, drop the hard paint into an empty pan, add a few drops of water, and let it soften overnight. It becomes a pan color. You can also mash it with a palette knife and a little glycerin to bring it back toward paste consistency, though it rarely returns fully to tube texture.
How to open a stuck watercolor tube
Run the cap under hot water for 30 seconds and twist with a rubber jar opener. If paint has dried in the threads, soak just the cap in warm water for ten minutes; because watercolor is water-soluble, this usually does the job. For a cap that has cracked, replace it with one from an empty tube or seal the neck with plastic wrap and a rubber band. Opening the tube from the bottom, decanting the paint, and refolding the end is the last resort, and it works fine.
Acrylic tubes stick for the same reason but the dried film does not redissolve in water; a drop of rubbing alcohol in the seam softens it. Oil tubes seize with oxidized paint and respond to mineral spirits instead. The hot water step is common to all three.
Common Mistakes With Tube Watercolor
- Squeezing out too much. You end up with dried mounds that take up palette space. Pea-sized is the rule unless you are mixing for a big wash.
- Painting straight from the tube everywhere. Undiluted paint looks flat and chalky and wastes pigment. Only the darkest accents need butter strength.
- Washing the palette clean after each session. You are literally rinsing paint down the drain. Let it dry and reuse it.
- Letting fresh colors touch. Wet blobs in adjacent wells merge. Space them out or use a palette with deep dividers.
- Dipping a dirty brush into the paste. A brush carrying another color contaminates the well. Rinse before you go back to a pure color.
- Storing tubes in heat. Hot cars dry out the humectant and tubes harden quickly.
Tips by Skill Level
Beginner
Start with six to eight tubes: a warm and cool version of each primary, plus a neutral like burnt sienna and a blue-black mixer. Squeeze them into a palette once, let them dry, and practice value scales from tea to butter with a single color until you can predict the dried result.
Intermediate
Keep fresh paste available for darks while using the dried wells for everything else. Learn which of your pigments granulate and which stain, because fresh tube paint exaggerates both behaviors.
Advanced
Mix large puddles for full-sheet washes using fresh paste for consistency, and premix the three or four dominant colors of a painting before the first stroke. Use tubes to refill a custom palette so that the layout matches the way you think about color rather than a manufacturer’s arrangement.
FAQs
Do you have to dilute watercolor from a tube?
Almost always. Tube watercolor is concentrated pigment paste. It only becomes transparent watercolor once mixed with water. Straight-from-the-tube paint is used for the very darkest accents only.
Can you let tube watercolor dry on the palette and reuse it?
Yes. The gum arabic binder redissolves in water indefinitely. Let the wells dry, then reactivate with a wet brush or a spritz of water next session.
How much tube paint should I squeeze out?
About a pea-sized amount per color for a small painting. Squeeze more only when mixing a large wash. It is easy to add and impossible to put back.
Why does my watercolor look chalky or opaque?
Not enough water. Thin the mix until you can see the paper through it on a test strip. Some pigments, especially cadmiums and certain whites, are naturally more opaque and need extra dilution.
Are tube watercolors better than pans?
Neither is better. Tubes mix faster and reach stronger darks; pans are compact and waste nothing. Many painters fill their own pans from tubes to get both advantages.
How long does a tube of watercolor last once opened?
Years, if the cap is kept clean and snug and the tube is stored at room temperature. Even if the paint hardens, it can be used as a pan color.
Next Step
Using watercolor paint tubes comes down to a small squeeze, a lot of water, and a palette you never wash clean. Once the dried wells are part of your routine, tubes become the most economical way to paint, and the fresh paste is there whenever you need a strong dark. The remaining frustration for most painters is storage: tubes rolling loose, caps going missing, and brushes mixed in with everything else. A simple holder fixes all three. The comparison of tube and brush organizers that keep every cap and tip visible walks through the options so your paint is ready the moment you are.
