RE: Fortespeed 412 (and a Question)

>> Loris Medici wrote:

So I decided to make trials with Ilfospeed RC
Deluxe (unfiltered speed: P500, filtered: P250, range with 00 filter:
140) and Ilford Multigrade RC Cooltone (unfiltered speed: P500,
filtered: P200, range with 00 filter: 180). I'll start my tests with
Cooltone because of slightly better range - and also it's more
sensitive
to green light: Deluxe is virtually "blind" over 480nm, ITOH Cooltone
maintains the same sensivity up to ~ 540nm...

Will expose placing a 00 filter behind the pinhole. Yes, I know this
will lower the EI but I want to make use of the better contrast range
with the 00 filter (curve slope is milder compared to unfiltered
exposure). Does this make sense for you?

Regards,
Loris.
_______________________________________________

Hi Loris,

This does make sense to me. Here is a link to a topic on Tom
Persinger's f295 forum. It shows a test I did last summer with and
without using a yellow filter to improve the tonal range.
http://f295.tompersinger.com/cgi-bin/Blah/Blah.pl?b=lab,m=1100713642

I did another test more recently using multiple layers of Rosco #7 gel
filters. The more layers of yellow used, the greater the range of
tones in the neg. The downside was that these are lighting gels and
are not clean like a filter made to be put over a lens. The more
layers of filter, the fuzzier the image became.

The question (to Loris or anyone on the list): I look at the spectral
sensitivity charts that come with paper or are in the manufacturer's
technical specification sheets on their websites. They make sense to
a point; I can read from them that an emulsion is more or less
sensitive to a particular wavelength of light. Could you give me (and
us) a little more information about what these charts are telling us;
or is there a link on the internet that would give a non-scientist a
good explanation?

Many thanks,
Tom

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Received on Wed Nov 17 10:09:49 2004