just finished my new 20x24 diy UV exposure unit. Going to try it out tonight with some digital negs and van dyke emulsion. Was using unit at school until covid. Now I can start printing again. Yeeehaw.
Most of the antique/alternative photographic printing processes need UV exposure, such as cyanotype, albumen, gum bichromate, platinum/palladium, etc. Some processes can be exposed by sunlight (natural UV) but exposure in a device like this is more controlled and repeatable.
For making contact prints using the so called 'alternative processes'... such as cyanotype, van Dyke Brown, salted paper and platinum/palladium to name a few.