P3D Re: "Grain" (PHOTO-3D digest 3478)

[bobh@xxxxxxxxxxxxxxxxxx]

RE: Mark Dottle et al!
 Hi, my explanation was to say that it is not the 'conventional silver 
grain' you have been taught about that you see in slides as the 
silver has been bleached out (also in color negs and Ilford XP films).
 Because the 'effect' of grain seen in a b&w print is really the 
spaces between the grain making up the image..it all becomes 
confusing. The color films have three layers of silver images used 
as mask to provide the postive image on reexposure before 
redevelopment with the color developer that adds or activates the 
dyes.The silver is then bleached out. The three layers minmize the 
spaces that will look like grain compared to a single layer as the 
'holes' don't line up,. Underexposure in a slide, does make areas 
that look mottled, blotchy, or even grainy if blown up enough BUT 
the original question said overexposure produced grain which is 
what I said was WRONG.. In the XP films of Ilford the more you 
'overexpose' the 400 film ((lower film speed) the finer grained the 
print becomes. 
The main thing that brought this to my attention was how much 
less grain a b&w from a Kodacolor neg had on Panalure paper (that 
used all three layers) compared to blue sensitive paper that in 
effect sees one layer. I was testing to see tonal differences but 
found the grainy effect too to be less. BobH
BOB HOWARD (bobh@xxxxxxxxxxxxx)
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