*** Am honoured to have my Lumen work featured over 7 pages in “The Experimental Darkroom – contemporary uses of traditional black & white photographic materials” by Christina Z. Anderson. https://www.alternativephotography.com/experimental-photography-workbook/
Purchase my own Lumen process book through Blurb! https://www.blurb.com/b/10686618-limitless-lumen
Lumen Printing 
is a contact printing process that can make use of aged and badly fogged silver gelatin photographic papers***. In this case regular (light sensitive) photographic enlarging paper is sandwiched in contact with objects, and exposed in full sun for a length of time (usually 20 min. – several hours). An ultra-violet light box can also be used for exposure.
The finished image does not require ‘development’.*** It is simply ‘fixed’ in photographic fixer chemistry and may be toned. Botanical specimens generally work best, because the plant juices can locally dye the paper, and induce formation of umbra. Extreme over-exposure to ultra-violet light can produce surprising colours from normal black and white photographic enlarging papers!
Prior to ‘fixing’ a print, one can ‘paint’ an image with normal print ‘developer’ to create local detail in the print. If the photographic paper is ‘painted’ with fixer, prior to exposure to the sun, you can achieve a ‘liquid emulsion’ look to your lumen print*.
Normal darkroom printing, can be combined with lumen….to achieve interesting combinations of B&W with colours of lumen, on the same paper*.
Photographic film can be used in place of light sensitive photographic paper, for lumen process. Again, the results may have beautiful colour tones. The film emulsion may be “painted” with photographic chemistry before, during or after exposure to add chemigram-type elements to the image, as one does with photographic paper*. This is a great way to make use of expired and badly fogged sheet film.
Left – Lumen-printed film image over a B&W darkroom print*
Galerie
Tiina Kirik 