Use real paint splatters in your artwork!
Remember that brushes can be a maximum of 2500 pixels by 2500 pixels, so ensure that the area of the brush shape falls within those dimensions. Always keep the size as large as possible – your current project may not need such a substantial brush, but your next project might.
Colour will be converted to greyscale, so if you would like to have a better idea of how the brush will look, you can convert to greyscale. It’s advisable to save a separate document just for the brush. Go to File>Save As, and choose a different filename. Then, go to Image>Mode>Grayscale.
Use a selection tool, such as the Quick Selection, to select the area you want to turn into a brush. With sampled brushes, you can’t adjust Hardness. So if you want a soft- edged brush, apply an appropriate amount of feathering via Select>Modify>Feather. For crisp-edged brushes, don’t apply any feathering.
Once you finalise the selection, go to Edit>Define Brush Preset. Name your brush in the subsequent dialog, then click OK. At this point you can start brushing away with your new brush, or you can edit its properties in the Brush palette. If you edit it, save it by going to New Brush Preset from the Brush palette menu.