You can solve this by doing a three-way test.  To do this, select a third ingredient that has known reaction values with the two ingredients you are attempting to pair, and which will adjust the color component that was clipping, so that it is no longer doing so.  Use this additional ingredient as the first ingredient in the new test and combine that with your two ingredients that clipped.  In Desert Paint Lab, you'll want to select a known pairing in the first two boxes, and the other ingredient in the third.  Desert Paint Lab can then do all the math to figure out the mystery reaction.

Example: Toad Skin and Saltpeter clipped with red too low. You know that Red Sand (high red) and Toad Skin don't react, so attempt a reaction using Red Sand, Toad Skin, and Saltpeter.

This application was developed using [MonoDevelop](http://www.monodevelop.com/), using the [Stetic GTK UI designer](http://www.monodevelop.com/documentation/stetic-gui-designer/).