[pure-silver] Re: Shoulder and highlight
- From: "John Black" <jblack@xxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 3 Jan 2005 12:57:37 -0500
>
> In my hand neither T-MAX 100 nor 400 has hump in their curves. T-MAX
> P3200 can have it. I'm curious how you got hump in TMX or TMY if it's
> what you are talking about.
Sorry to get into this a bit late. Too much holiday high living.
HD curve linearity (or lack of it, as in "hump-backed") can be developer
related. Highly active, alkaline, concentrated film developers tend to have
a longer linear phase of the curve than diluted, low pH products. I have
seen curves published (I will find out where and pass it along) that show
the difference in curve shape between D76 neat and 1:1 with Kodak films and
there is a marked difference in overall shape. Think about it, low pH
developers tend to loose some low exposure density with fast films but pick
it back up in the midtones and highlights, thus giving a "hump" to the
curve. Diluted developers tend to run out of gas in the highlites before
shouldering out, giving the same shape.
All I wish to do is remind everyone that there are several factors at work
in determining curve shape, and film charateristic (properties) is just one
of them.
If this subject has been done to death in the last few days, my appologies
as I have not finished reading all of the backed up emails from the
holidays.
Happy new year..
JB
>
> --
> Ryuji Suzuki
> "Keep a good head and always carry a light camera."
>
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