| Open a new image 100x100 with a white background. |  |
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Now select Image/Noise/Add with setting; % Noise=any (I did 75%), Uniform or Random (I selected Uniform). It all depends on how granular you want your background to be. |
| Select Image/Blur/Gausian Blur Radius=1.00. |  |
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Now choose Colors/Grey Scale, then Colors/Increase to 16 million. |
| Now Colorize by selecting Colors/Colorize and setting the Hue and Saturation to obtain the desired effects. |  |