[alt-photo] Re: gum contrast...

[Paul Viapiano]

Katherine and Loris...

Please don't go through any big deal about this. I'm coming to terms and 
re-examining the basic tenets here, and basically thinking out loud about 
all this in theory. Of course, in gum, practice is another thing.

But all in all, just batting a few ideas around in my head. I apologize to 
all about my constant stream here...someday I'll learn to just sit back and 
enjoy this ;-)

Paul



----- Original Message ----- 
From: "Katharine Thayer" <kthayer at pacifier.com>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Monday, May 17, 2010 9:21 PM
Subject: [alt-photo] Re: gum contrast...


> Paul, I am literally too tired to think tonight, but I have this  vague 
> idea that there was a discussion about this on the list a year  or two 
> ago, and that I may even have done some testing.  I did a  quick search at 
> the archives but didn't come up with what I was  looking for.  It seems 
> like it wasn't exactly this question but was  masquerading as this 
> question, or something like that, but I don't  remember the discussion 
> exactly.  I'll look again in the morning.
> kt
>
>
> On May 17, 2010, at 4:00 PM, Paul Viapiano wrote:
>
>> Hi all,
>>
>> Thanks for the comments on my last question. Sodium bisulfite  helped 
>> restore brighter colors but yes, not overexposing in the  first place is 
>> good advice.
>>
>> Riddle me this, sil vous plait: Knowing that decresing dichromate 
>> increases contrast, what would be the difference between a mixture  of 
>> 2:1 gum/dichromate and a mixture of 1:1 where the dichromate is  1/2 
>> strength, both at the same exposure time?
>>
>> Katherine mentions in her website that halving dichromate reduces  speed 
>> by approx one stop. If you halved the dichromate, and  increased the 
>> exposure by two, would you effectively get the same  print as a 1:1? I'm 
>> trying to see relationships in theory here...
>>
>> Thanks in advance...Paul
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