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substitute PPD by CD-3

olk

Member
Joined
Jul 28, 2020
Messages
107
Location
Germany
Format
Medium Format
I'd like to mix Jay DeFehr's Halcyon developer but my local dealer doesn't sell PPD.
CD-3/CD-4 are available.
At which ratio do I've to substitute PPD by CD-3?

Oliver
 
This thread might be useful, but one thing to consider is that CD3 is less active than PPD.
 
olk said:
I'd like to mix Jay DeFehr's Halcyon developer but my local dealer doesn't sell PPD.
CD-3/CD-4 are available.
At which ratio do I've to substitute PPD by CD-3?

Oliver
Click to expand...

Interestingly Jay himself gave up on Halcyon, probably due to instability caused by ascorbic acid, and recommended using GSD-10, a developer that doesn't use PPD:

"I formulated my own developer of this class, and while it produces excellent results, I find it impractical in my low-volume darkroom, and generally obsolete considering the fine grain qualities of modern emulsions and the loss of film speed and sharpness. For example, TMY developed in stabilized Halcyon (my formula) produces film speed of about EI 250, with virtually no grain in a 10X enlargement. Fuji Acros 100 exposed at EI 200 and developed in GSD-10, a one-shot glycin developer, results in similar grain and gradation, but much greater apparent sharpness, without all the hassle associated with maintaining a large tank replenished system."
 
CD-2 works well for b&w dev I found in the past when I used it. Its available at artcraftchem I believe.
 

Jay DeFehr made this statement in 2007 (digitaltruth.com) but announced and praised Halcyon at https://www.largeformatphotography....?71010-Halcyon-superfine-grain-film-developer and https://www.photo.net/discuss/threads/superfine-grain-film-developer.434467/ in 2011.
Seams that Jay didn't gave up on Halcyon.
 
If PPD and CD-2 are both unobtainable you could try CD-3 in molecular proportion as I was told by Gerald Koch in post 2 below.
ie for every 108 g of PPD required use 418.5 g CD-3
https://www.photrio.com/forum/threads/replace-ppd-by-cd-3.68079
The pH could be adjusted, by Hydrion pH paper the pH of my Halcyon is slightly less than 8.
Your gaff, your rules as in the UK pub trade.
 
But Ian Grand responded in the same thread:
"Activity is not in step with Molecular weight..."
 
olk said:
But Ian Grand responded in the same thread:
"Activity is not in step with Molecular weight..."
Click to expand...

You need to not only factor in the difference in activity of the two reducing agents (PPD vs VD3) but also their super-additivity with ascorbic acid. It will be an interesting exercise in tinkering and good luck.


You're right. I had another PPD-based developer of his in mind but mistakenly thought it was Halcyon.
 
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