From: Eric Neilsen (e.neilsen@worldnet.att.net)
Date: 05/17/00-01:33:57 AM Z
Nick, First I would love to come back to northern California. I grew up in San
Jose and lived in SF during the mid to late 80's.
Back to Platinum...... I'm sure that over the years several discussions have
included the use of temperature of the developer to control contrast. Warm
gives a softer image and cooler giving a print with more contrast. If you are
using Potassium Oxalate you might find that a simple change from room temp to
say 85 to 90F will bring you into where you want to be. It will also warm your
print color. Mike Ware printed his findings on the platinum and palladium
contrast curves. There are two platinum formulas, one using potassium and the
other ammonium. The ammonium based platinum salt has a higher concentration.
It does effect contrast more. When you start playing with contrast control by
using temperature and or coating mixture of your PT and PD your print color can
move all over the place. So if you want a specific look, than you need to
balance the changes to keep you with a print color that you want.
Much of what Mike Ware writes about in his paper on PLatinum printing ( about
1986) applies not only to the ammonium based ferric, but broadly throughout the
many combinations.
It sounds like you can print your own step scale from your zip disk info and for
go any densitometer. ( assuming your service people are consistent with their
output?)
Nick Makris wrote:
> Judy and Eric,
>
> I also have recently printed a 21 step negative which didn't provide any
> enlightenment - it printed just fine. Once again, I have no densitometry so
> I am unable to compare the steps to the areas in question.
>
> There is one point I must reiterate here - the problem I'm experiencing is
> *very subtle*. Not a huge deficiency that makes the print unsalable, but
> one that many on this list (several names come to mind) would be sure to
> question. I may be expecting more than the process is capable of.
>
> Maybe one of you would like to spend a weekend on the beautiful Mendocino
> coast and make a personal assessment - I live in a planned community
> overlooking the Pacific, called Sea Ranch on the Mendocino/Sonoma County
> line in Northern California.
>
> Eric - I am very interested in your suggestions regarding temperature and
> the mixing of PT & PD to control contrast. I have nothing in my archives on
> this and I don't believe I have ever read about either method. Is there
> anything posted that you can recall?
>
> Once again many thanks,
>
> Nick
>
> PS After preparing this post, I realized that I do have a densitometer of
> sorts (Photoshop).
> I pulled out the ZIP disk that the neg(s) were prepared from (6 in one TIF
> file) - created as a Photoshop file and saved to the Zip Disk as a TIF file.
> The areas in question on these prints are much to close to the high and low
> ends of the spectrum - 0 and 255. When creating these images, I took great
> care to make sure that no area was below 10 or above 240. At some point
> during the conversion to TIF, the range changed - will need to test that.
>
> Thx
-- Eric J. Neilsen 4101 Commerce Street, Suite #9 Dallas, TX 75226 214-827-8301 http://e.neilsen.home.att.net http://www.ericneilsenphotography.com
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