Bob since you are canadian you probably had some french in school so you can probably contact the Fresson family and get some informations regarding the homemade enlarger it seems they used this method only for the mono fresson process and not the four colour process which requires separations negatives. They used an arc lamp for cinematic projectors as UV source and built the enlarger around it. Note: Rodenstock made a UV enlarger lens the UV-Rodagon.