Two paints you already own are enough to see how colour mixing works. Make three mixtures between them, dilute each once, then let the samples dry. The small strip that results shows which colour dominates, how water changes strength and how a mixture settles on your paper.
Watercolour can make the same mixture look several ways. A deep puddle may dry lighter, and a balanced wet mixture may look different once dry, sometimes leaning towards one of its colours. More water lightens a mixture by letting more paper show through. It does not change the balance between the paints.
At a glance
Work with two colours at a time. You can see what each paint contributes and repeat a result more easily.
Change proportion before changing water. First alter the balance between the two paints. Dilute the finished mixtures afterwards.
Judge the dry sample. Wet paint usually looks stronger than the colour that remains after evaporation.
Treat colour names as a starting point. Two blues with a different lean may produce noticeably different greens or violets.
Keep a small record. Paint names, paper and a few notes are enough to turn an experiment into a reference.
Start with the paint already on your palette
You do not need a specially chosen mixing set for this exercise. Pick two paints from your own box that should make a recognisable third colour, such as a yellow and a blue, a yellow and a red, or a red and a blue. A pair with a clear visual change is easier to read than two colours that are already close together.
The first and last squares of the strip below hold each colour on its own. They give you the two endpoints for the mixtures between them, and they show the strength of each paint. One may colour the water quickly while the other needs more paint to reach a similar depth. That difference matters more than an exact recipe based on equal drops or equal brushfuls.
Use a pale mixing surface so you can see the puddle. Keep clean water nearby and rinse the brush fully before returning to either colour. If the palette puddle looks weak before it reaches the paper, the water guide explains how to judge paint strength without relying on a universal ratio.
Why two blues can mix two greens
Paint labelled blue is still a particular blue. Some blues appear to lean a little towards green; others appear to lean towards violet. Yellows and reds also sit in different places within their colour families. This tendency is often called colour bias, although warm and cool labels are relative to the colours placed beside one another.
The difference becomes clear through comparison. Mix one yellow with two blues that have a different lean. One pairing may produce a vivid green while the other produces a quieter, greyer green. Neither result is automatically better. The more useful question is which result suits the passage you want to paint.
A comparison painted with your own paints is more dependable than assuming every colour with the same name will mix alike. If a label shows more than one pigment code, the guide to single-pigment watercolours explains what that means for mixing.
Practical test
A first mixing strip with two paints
Rule five squares in a row, about 3 cm each, on a spare sheet of the paper you normally use. Leave a gap of about 5 mm between them so wet neighbours cannot run together, and leave room below for a second row.
- Put a puddle of each paint on your mixing surface, each flowing and glossy and about equally wet, as described in the water guide.
- Paint the first colour in square 1 and the second colour in square 5.
- Mix three generous puddles: mostly the first colour with a little of the second, about equal amounts, and mostly the second colour with a little of the first. Judge the balance by eye.
- Paint the three mixtures in squares 2 to 4, and keep the rest of each puddle.
- Add clean water to each saved puddle, about its own volume again, and stir. Paint a paler square directly below squares 2 to 4.
- Leave the sheet flat and untouched until it is dry. Then compare the dry samples with what you remember seeing while they were wet.
The strip separates two questions: what happens when the balance of the paints changes, and what happens when the same mixture receives more water. It does not need to be neat to answer them.
| What you change | Keep the same | Where you see it |
|---|---|---|
| Balance of two paints | Wetness of each puddle | Across the top row |
| Water added to a mixture | Paint pair and its balance | Between top and lower rows |
| One paint in the pair | Paper, method and other paint | In a second strip |
Proportion and water are different controls
Adding more of one paint moves the mixture towards that colour. Adding clean water makes a mixture paler and lets more of the paper show. The balance of the two paints stays the same, though a very pale version can look slightly different in hue, which the second row will show.
The controls can look similar on the palette because both change the puddle. Test them separately. If a green is too blue, add yellow rather than water. If the green is the right kind but too strong for the passage, dilute a portion of it. This distinction prevents a great deal of uncertain adjustment.
A small amount of a strong colour may dominate a larger amount of a gentler one. Descriptive notes such as “mostly yellow” or “a touch more blue” can therefore be more useful than an exact ratio.
Watch what changes as the paint dries
You mix watercolour wet and judge it dry. As water leaves the sheet, many mixtures become lighter and some differences become easier to see. Granulation, separation and the texture of the paper may also become more visible.
Before the strip dries, write one short prediction beside it: perhaps “the centre will stay green” or “the blue will take over”. Return when the sheet is matt and at room temperature. Note what actually happened. The gap between prediction and result is the useful part.
Avoid correcting a sample while it is drying. A second brushstroke introduces another variable and can disturb the settling wash. If you want a stronger version, make a separate swatch or wait until the first is completely dry before deciding what to test next.
Keep a record you will use
A mixing notebook does not need to contain every possible pairing. A few labelled strips from colours you use regularly are more helpful than a large chart you never consult.
Record the two paint names, the maker, the paper and the date. If the label gives pigment codes, add them without turning the page into a catalogue. Mark which side of the strip contains more of each colour, then add one practical observation: “clear spring green”, “quiet violet”, “useful shadow colour” or “dries much lighter”.
When a mixture becomes useful in a painting, put a small dot beside it. Over time, those marks show which combinations have earned a place in your working habits.
When a mixture surprises you
First let it dry. If the colour is right but too pale, repeat it with a stronger puddle. If it leans the wrong way, alter the balance between the two paints. If it is duller than expected, try a different red, yellow or blue from the colours you already own and place the results beside one another.
Keep the test to two paints while you compare. A third colour can be useful, but it makes the cause of the change harder to see. Quiet greens, browns and greys are central to many paintings, so a subdued mixture is not a mistake in itself. What helps is knowing whether you made it deliberately.
Begin with one pair and five squares
Begin with one pair of paints and five squares. Change the balance of the paints across the top row, dilute those mixtures underneath, and judge everything once dry. Repeat the format with another pair when a painting gives you a reason.