Two basic general features that characterize brushes set limits on what can be successfully turned into a brush. And what can be a brush is almost anything.
- First is color. Photoshop uses gray scale info while defining brushes. You can make a brush out of a colorful image but converting your document to Grayscale will give you a better idea of what you are doing. Anything that is white becomes transparent (0% opacity), anything black becomes 100% opaque and any other color turns translucent (opacity somewhere between 0 and 100%).
- Second limitation is size: there is a maximum brush size possible. From Photoshop 7.0 on it's 2500 px x 2500 px (and 999 px for earlier versions). The larger the brush is created the better, so we strongly encourage you to create large brushes (ideally about 2500 px x 2500 px). The reason is you can’t increase the diameter of your brush beyond its original size without blurring.
