That sounds like a resource worth hanging on to. Thank you for the information.
Janet Gable Cull
Sent from my iPhone
On Jun 25, 2018, at 5:47 PM, <mark@xxxxxxxxxxxxxxxxxx>
<mark@xxxxxxxxxxxxxxxxxx> wrote:
Once in a while you may get really lucky and find that it is something that
might be irreplaceable. Developing one roll likely would give you an idea of
what might be on the other rolls. If happen to get images from that trip of
a lifetime, they won't be cheap, but Film Rescue has some proprietary methods
they use to get the best out of what is there. I wouldn't consider it worth
the expense unless its something really special, but its an option
-------- Original Message --------
Subject: [pure-silver] Re: Exposed old HP5
From: `Richard Knoppow <dickburk@xxxxxxxxxxxxx>
Date: Mon, June 25, 2018 2:46 pm
To: pure-silver@xxxxxxxxxxxxx
Thank you, I have been unable to find my earlier Ilford
literature.
This is slightly shorter, by about 30 seconds, for each
dilution. Slightly longer development would make very little
difference.
Kodak never gave development times for D-76 diluted 1:3 but
Ilford does for ID-11, their equivalent. When diluted 1:3 either
developer becomes an "acutance" developer. I found D-76 was
somehow unpleasant looking and think ID-11 would be the same. Too
much acutance effect. On 35mm it looks like someone drew pencil
lines around things.
Something I should add: I described the ISO/ANSI speed
measuring method in rather boring detail earlier. However, at
some point, maybe twenty years ago, Ilford announced they were no
longer using the gamma or contrast values in the standard. Their
logic was that most users wanted somewhat lower contrast, so they
chose a value in between the diffusion value and the condenser
value. This results in a slightly increased exposure and slightly
reduced development. For most films the difference in contrast
is about one paper grade and results in a speed variation of + or
- 3/4 stop. The amount of change in development is about 25% t o
30% for cubic grain films and about 20% for tabular grain films.
This more rapid change in contrast with development time is, I
think, one reason tabular grain films got a reputation for being
overly contrasty and difficult to control. They are neither but
require closer control of temperature, time and agitation than
conventional films. Ilford's speeds result in negatives that can
be printed with either type of light source with minimal
adjustment of printing contrast. They evidently adjusted the
emulsions to get conventional box speeds.
There is sufficient information in the ISO/ANSI standard to
work out these variations to get the speeds that one would get
using the "standard" contrast and method.
Also note that there was an earlier DIN speed method. The
one on which the ANSI/ISO speed is based came out about 1960,
don't remember the precise date. It works on a different
principle than the early DIN method. One can find early DIN
speeds in very old books, the two should not be confused.
On 6/25/2018 11:29 AM, Asmo Saarikoski wrote:
Hi Janet,--
I have an Ilford data sheet from 1977 in front of me. Their recommended
times
for HP5 and ID-11/D-76 are (at 20 deg C / 68 deg F):
undiluted 7 minutes
1+1 12 minutes
1+3 23 minutes
Hope this helps,
Asmo
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.
