This page lets you experiment with color deconvolution without downloading anything. You can sample the undesired, desired, and background colors from the image, with a sample size of 1x1, 3x3, or 5x5 pixels. You can then deconvolve the image. You can also store and recall your sampled colors from memory. That memory orginally contains the ideal color samples.
You can experiment with any of the images above.