(Tom, I changed you subscription address as your domain name seems to
have changed)
--------------------------<included message follows>---------------------
On Wed, Jun 12, 1996 3:11:53 AM, Peter Marshall wrote:
>In-Reply-To: <31BCF7D9.3F54BC7E@sedal.usyd.edu.au>
>
<< Can someone explain to
<<me the "correct" way to determin density range with a step wedge. SNIP>>
>First I would suggest you never use the term density range without saying
>what you are determining the density range of. The step wedge tells you
>about the density range of the negative that will record on your print. It
>tells you nothing about the density range of the print.
>
>Most step wedges that I have used have density steps of 0.15, which means
>that 2 steps are equivalent to one stop.
>
>Note that this does _not_ directly relate to the stop readings you would get
>using a spot meter on the subject - the separation of these on the negative
>will depend on the development you give the negative.
>
>You'll excuse me if I am stating the obvious, but it was not clear from the
>way you asked the question. If you are likely to be teaching this kind of
>thing I would recommend a practical study using one of the many good books
>related to the subject.
>
>Peter Marshall
>SNIP>
Thanks for the reply, I am requesting info on determining the density range
of negatives, I'm quite well versed in "zone system" work for compressing /
expanding a "real world" image into a negative to fit fit various
processes. My question is: how is the "official / standard" rule applied
to negative density range figures. Is it from threshold of detail to
threshold of detail (zone 8 minus zone 2) (what I use in my own work) or
from threshold of tone to threshold of tone (zone 9 minus zone 1) or from
maximum to minimum density (zone 10 minus zone 0). I am aware that my (and
apparently your ) Kodask step wedge is in 0.15 (1/2 stop) increments.
Perhaps part of the confusion is over my practice of reffering to negative
density in "stops" as opposed to "density units". I truely have worked in
isolation in referance to alt processes (discovering this group is a great
help!!). When I said a "5 stop range" I ment a 1.5 density unit negative
(I hope??). By the way, I am unable to find the "Stoffer" 1/3 stop (0.1
unit) step wedge anywhere, does anyone have a source in the USA??