[pure-silver] Re: HC-110 vs D-76

HC-110 was originally developed by Kodak in 1965 for commercial processors as 
an alternative to several of their other developers.  This is evidenced by the 
large number of dilutions that are specified.  The intention being that a 
certain dilution of HC-110 could replace a developer such as DK-50 without the 
need to change machine processing times.

The developer slowly gained a favorable reputation outside of the commercial 
area.  It was a favorite of Ansel Adams and of those using the zone system. 

While the chemical composition of HC-110 is very different from that of D-76, 
both developers produce very similar negatives.  The 2001 Kodak Professional 
Photographic Catalog contains the following comparison. 

Compared to D-76, HC-110 (dilution B) produces: 

o Slightly less shadow detail or true film speed.
o Better separation of the highlights in a negative. 
o Slightly finer grain.
o Slightly lower acutance.

Like Rodinal, HC-110 concentrate has a very long shelf life even in partially 
filled containers.  It is best not to follow Kodak's recommendation of making a 
stock solution for further dilution as the stock has a very limited life.  
Rather make dilutions directly from the concentrate.

My favorite dilution is 1:50 just like Rodinal.  At this dilution acutance is 
very good.  Use the recommended times for dilution E or develop for 1-1/2 X the 
recommended time for dilution B.

For a very imformative discussion of HC-110 go to 
http://www.covingtoninnovations.com/hc110/

Jerry

-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx 
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Bogdan Karasek
Sent: Thursday, August 24, 2006 8:47 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] HC-110 vs D-76


Hi,

I just got back from the photo store and they were out of D-76 on the 
shelf.  While somebody was getting more from the storeroom, I asked if I 
could replace D-76 with HC-110.  On more than one occasion, I have heard 
say, that the only difference between the two was that one was liquid 
and thus easier to mix as opposed to D-76 where you have to heat the 
water to 120°F and so forth.  Tonight, I was told that they are similar 
but that HC-110 gives a higher contrast but that If I played around with 
the dilution, it could probably give comparable results to D-76.  This 
is contrary to everything that I have heard up till now.

So what is the difference between the two?  By the way, I use D-76 to 
develop Tri-X (200 asa) for 10.5 minutes, 68°F.

Cheers,
Bogdan
-- 
________________________________________________________________
   Bogdan Karasek
   Montréal, Québec            e-mail: bkarasek@xxxxxxxxxxxx
   Canada

                   "I photograph my reality" 
__________________________________________________________________


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