photo editing programs

[Kirk Keyes]

So - silver halide TYPICALLY have only TWO states. on or off. Hit with enough energy to trigger a reduction reaction or NOT hit with enough energy to trigger a reduction reaction.

But that reduction is completely dependant on the development step of the film processing. An individual grain of silver halide may begin development, but it does not have to develop fully. So there is no direct 1:1 function for grain exposure to density in the final film. The grain may develop fully, or it may not complete the reduction process before the development step is over. And the type of developer can change the shape and therefore the resulting density of the partially or fully developed grain.

Even though the input step appears to be binary, there is absolutely nothing binary about the results.

[JW Dewdney]

Well - that's semantics. I suppose you could say exactly the same thing about a digital dithered bitmap image if the dots are small enough. I think the original poster wasn't trying to equate the two unequivocally so much as make a suggestive point.