[pure-silver] Re: New color head "discoveries"
- From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
- To: "'pure-silver@xxxxxxxxxxxxx'" <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 13 Jan 2005 13:56:02 -0500
I adjust my film development times to yield negatives that print with normal
contrast on VC paper *without* any filtration. Depending on the brand of paper
this is comparable to a grade 2 to 2-1/2 graded paper. This usually requires
developing for longer than the manufacturer's published times (which seem to be
for condenser enlargers).
Agfa is the only manufacturer that I know of that publishes film development
times for different gammas (CI or whatever). I use filtration only for those
negatives which need some tweeking.
Jerry
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of Rob Champagne
Sent: Thursday, January 13, 2005 12:56 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: New color head "discoveries"
big snip
> The filters of a color head will not give you the full
>range of contrast available from VC paper with the use of
>dedicated filters. They should give you a couple contrast
>grades on either side of "normal" but filters should be used
>to obtain the maximum and minimum contrast values.
big snip
>---
>Richard Knoppow
I wonder whether my observation is true for other dichroic filter head
enlargers. The Ilford Y+M figures for grade 2 on my Durst CLS501 head enlarger
give approx an ISO grade 1 result on paper. It occurs to me that because
dichroic filtration does not seem to give as much contrast as filter sets, and
because most new enlargers have dichroic heads, that Ilford, and maybe other
manufacturers, use this to its advantage in terms of film speed.
To get a true ISO grade 2 using ilfords G2 Y+M figures for my enlarger I have to
give the negative more development which in turn gives allows a faster film
speed. So what I'm speculating here is that modern film speeds may be tailored
by the manufacturers to suit printing on dichroic heads with Y+M filtration. It
should be noted that by using increased development of the negative the overall
contrast obtainable from a dichroic is not far short of a true G5 and if you
take neg development far enough then a true G5 is obtainable from a dichroic
head.
It all depends on what you are tailoring your development to. Do it to 0
filtration and your negs will be too soft for G5 on dichroic settings. Do it to
G2 Y+M settings of your dichroic head and you will get faster film speed and
availability of higher contrast in your print.
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