Welcome back to Photography Monday. Today we are going to talk about chromogenic black and white films or simply put black and white films that can be developed in color chemicals. Today a technical lesson and a review is presented.
Okay so we know what chromogenic black and white film is, now lets get into details on how it works. As you may know all traditional film works with a silver halide emulsion that is sensitive to light. Most color films work by coupling this to multiple color dyes. When color film is processed the silver halide is developed and the color dyes are activated in the exposed areas. The developed silver is then bleached back into silver halide and fixed away, the color dies are then stabilized and the color image remains. This is known as chromogenic film. Now chromogenic black and white film works the same way, but instead of multiple color sensitive layers and color dyes a single panochromatic layer and a black dye are used.
What films are available and what are the differences:
This is where things get tricky. There are only two films out there and they vary quite a bit. Both films are 400 ISO. Also with both films you should tell your photo finisher that you want the prints in black and white, otherwise you may have color tints.
First you have Kodak with BW400CN. Kodak's offering is designed to directly drop in into all color processes both those using optical printing and for modern systems using scanning and digital printing. This means the film still has the orange base used by most color negative films and that printing optically with black and white paper is an issue though. Kodak's offering is available in 36 exposure 35mm rolls. You may still find some old stock or the recently discontinued 24 exposure rolls. This film is not available in medium format.
The second offering is Ilford's XP2 Super. This film has a clear base and can be printed by both the scanning method used most modern labs and optically printing to black and white paper. There will be color tinting when printing optically to color paper. Ilford's offering is available in 35mm with 24 and 36 exposure rolls, a 100 foot bulk roll, in addition to a 27 exposure single use camera. Ilford's offering is also available in 120 rolls as well.
I recently shot a roll of BW400CN I picked up at LA Cameras in Chambersburg, Pa. The film is a nice 400 ISO film similar to T-Max (in fact the emulsion is the same purple color) with the tabular grain. Contrast is great if not a bit high. Latitude is similar to that of color print film. The tones in the images are represented very accurately. I let the LA Cameras know that the images were in black and white and the equipment was set up accordingly. Every image came out great except for the one trick shot I did and that was photographer error and the film performed properly. I would recommend this film. This example was taken with this film and a Canon EOS Rebel G: