If you join the Dead Link Removed you can find a tutorial/manual in the files section entitled "Colour Enlarging Without Tears." It's intended for users of the Philips PCS line of enlargers, but despite the hype about the Tri-One light source, the basic procedure is the same for conventional subtractive enlargers. Also, this guide was written before the days of RA-4, so the details of the chemical steps are different. For that, you're best off following the instructions of the manufacturer, since details can vary slightly from one brand to another, even with the current crop of chemicals. If you don't want to join the Yahoo group, PM me and I can e-mail you a copy of the file (it's about 1.5MB in size).