Optimal filter combinations for photographing SYPRO orange or SYPRO red dye-stained gels

Photography or electronic image acquisition is required to document results obtained from staining protein gels with the fluorescent SYPRO dyes. We found that, when using Polaroid type 667 or 57 instant films, the choice of optical filter combination and photographic exposure time strongly influences protein detection sensitivity limits. Ultraviolet light-blocking Kodak Wratten No. 2A and 2B gelatin filters autofluorescence when illuminated at 300 nm. The use of these filters in combination with Wratten No. 22 or 25 filters or SYPRO gel photographic filters gives rise to increased background signals, which for long photographic exposures can obscure signals due to protein bands. Surprisingly, the use of these same ultraviolet lightblocking filters enhanced the protein detection sensitivity obtained with short photographic exposures. Under the conditions tested, we found minimal differences in performance for Polaroid type 667 and 57 films.