I have a set of cross processed Sabattier effect prints in my gallery and they are color. Nothing is simpler. Just flash during development. With B&W prints it should be white light and with color it can be white light or colored lights. Use normal development and flash about 3/4 of the way through.

BTW, I stick to the "real" name of Sabattier effect. This is not to put anyone down, but with the loss of all analog science and scientists looming on the horizon, in the future how will anyone really know what is being talked about if terms are corrupted? In fact, the change (or corruption) in nomenclature that happened in the early part of the 20th century is what causes a lot of confusion here and elsewhere regarding analog photography. I could give dozens of examples of this, but don't worry, I won't!

And so, Solarization is done in-camera and Sabattier effect is done during processing. They look quite different.

There is a long thread here that discusses methods in detail.

PE