Michael wrote:
> I'm not sure why one would need a projection wedge, perhaps someone could
> explain what they are used for. The 21-Step is much smaller. Price can
> vary dramatically depending of if you want them to calibrate it on a
> densitometer for you.
Using a wedge in contact with the sensitized medium tells you the exposure
range of your medium. If you are going to contact print your negative, it
also tells you what negative density range will give you the full range of
print density values (or alternatively, the print density values you care
about, if not the full range). However, if you project your negative onto
the sensitized medium, flare in the projector (enlarger) lens will spread
some of the light from the negative's low-density regions (the print's
shadows) into the highlight regions, reducing highlight contrast. If you
want to know how much (it's significant, even with multi-coated lenses),
you need to project the step wedge, too.
Best regards,
etienne
Received on Fri Dec 9 17:12:26 2005
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