QTR-Quadtone RIP

Whether one is better than the other is open for discussion 
but there are more differences than one would expect at 
first sight.

Color photography reduces the color spectrum already to 3 or 
4 hue separations. Digital to RGB, analogue to CMY (in some 
cases there's an extra one). Translating that to B&W (with 
and without digital filtering)  is different to shooting 
(with and without lens filters) the real life, full spectrum 
on a B&W emulsion  that has a continuous color sensitivity 
curve (panchromatic, orthochromatic, etc). There are camera 
integrated and external digital B&W converters with a choice 
of color sensitivity simulations (film choices) + the usual 
B&W color filters. A simulation though as there is no full 
spectrum available to start from. Digital B&W sensor cameras 
(usually customised color ones, often for infrared B&W 
photography) exist for several reasons. Removing the 
anti-aliasing filter and Bayer RGGB separation filter brings 
the camera closer to analogue B&W film. The basic color 
sensitivity (infrared bias!) however is not similar to 
existing B&W film but lens or sensor filters can change that.


For analogue photography and scanning film afterwards there 
is also the issue what scans best. Normal B&W films are 
harder to scan than color negative due to the usually higher 
Dmax. Color negative also gives better latitude in the 
camera in most cases but is also subject to the hue 
separations described above and there is the orange mask to 
deal with. B&W chromogenic film is something in between, 
scans well and acts like a normal B&W film in the camera.. 
Existing C41 processing labs will stay around for a while 
but the number of them is lot less than in the past and not 
all film formats can be developed as easy as it was 5 years 
ago. The grains or better dye clouds of color film and 
chromogenic B&W film are different to B&W emulsion grain. In 
the translation through CMY or monochrome dye layers>RGB 
pixels>B&W pixels you get another image structure than with 
scanning B&W film. Easier in editing afterwards though. With 
normal B&W scanned film that has the grain more or less 
resolved some issues can appear in editing as the tonal 
distribution is both pixel and grain related. Sharpening for 
example will influence the tone curve at the same time.


Some of what I described above but more subjective motives 
as well must have resulted in the fact that I still use 
normal B&W film in my MF folder cameras next to color 
negative and I can count the B&W images that were made on 
color negative film on one hand. Most likely I will still 
carry a B&W MF film camera when I finally have a DSLR (must 
give up on that idea that an equivalent affordable DRF will 
appear next year). Maybe I need that switch in gear to make 
the mental switch between B&W and color content in the real 
world.

-- 
Met vriendelijke groeten, Ernst


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