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By layering one color on top of another, you can lighten or darken it to accomplish the hue you have in mind. This should be done lightly and with as few strokes as possible. You can always add more of your layer color, but once added, it'll be difficult, if not impossible, to remove. You can lighten dark colors with a layer of a lighter color, like white, over top. This can also help with softening colors, like the one found in skin tones. This tool looks like a clear colored pencil and it is intended specifically for blending colored pencils. It is sometimes referred to as a colorless blender. Rub this tool firmly upon the colors you are trying to blend and pass it back and forth until the desired level of blending is reached. By spreading a thick layer-color over a base-color with your blender pencil, you can create a glaze effect over top the base. This will also impart a blended effect to your artwork. With a moderately stiff bristle brush, you can drag colors you've already applied to the page around it. Thin coverage will give your colors a lighter tone; thick concentration will intensify the color. Colors spread together will blend. You may have to experiment with this and get some experience before you become fully comfortable with the technique. You should choose your brush with regard to the paper you have used. Thicker paper may allow you to use stiffer brushes for easier blending. Thinner paper might require a soft bristle brush and gentle blending over time. You should also be able to use a tortillion to push colors around the page to create either increased or decreased brightness. Though paper and tortillions won't be effective for blending, a cloth can be used to smudge colors together to attain this look. You may want to start by smudging a small, inconspicuous area with a tiny piece of cloth to see how the colors blend before attempting to blend the main parts of your art. Some cloth might blend differently than others or create a unique effect in your drawing. Testing your cloth beforehand can prevent unintended effects when blending.
Layer your colors to create a blending effect. Utilize a blender pencil. Spread colored pencil with a bristle brush. Smudge colors to imitate blending.