But creating tones in watercolor is very important. Sometimes it is even more important than the color itself. To draw an analogy, a pianist for example might be good at reading sheet music and might have perfectly disciplined fingers to run throughout all the keys with ease but if he cannot coordinate his feet on the damper pedal, the resonance of chords will overlap and so will every key pressed that instead of music, all that is produced is a cacophony of noises. Watercolor art works the same way. As Henri Matisse once said, “There (a painting) should be a relationship and a living harmony of all the tones”.
Tones could be created with all colors, although lighter colors such as yellow will have less color tone possibilities than the darker colors such as reds and blues. Even so light colors could appear darker when surrounded by darker colors. This is also a tonal variation, a color illusion if you will that artists use and make adjustments but who gained first an understanding of color behavior.
Every good artist has to different degrees, practiced first on a grey value scale. A grey value scale is separated into 10 sections with the topmost color being pure white and the remaining nine is shaded 10% increments darker until the tenth or the bottom color is black. Comparing color tones based on the grey value scale gives the artist a very good idea on how color tones differ and how best to apply it. It also allows the artist uniformity on color tone application.
To achieve a good command at color toning, practice by painting a grey scale using black and white paints. Start with a white block at the opposite end and a black paint at the other and mix them in different range of grey. If you are starting from the darkest color the best way that this is done is to apply water as you go up the scale.
Once you can paint well with grey values, you can apply the same method with the colors that you use frequently. After that you can paint a value scale of all the colors that you have in your palette. These value scales will prove very important when you do actual watercolor work, as these tones are what you will use for color and tone referencing.
While working on the grey scale, you might be tempted to use white as you go to the lighter shades of grey. When painting a color scale however, it is not advisable since the color intensity will be lost. This practice always provided artists a very good working idea on how tones are created. Painting in tones is time well spent.