[pure-silver] Re: under-developed?
----- Original Message ----- From: "Agnes" <frcontrone@xxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, February 19, 2007 10:58 AM
Subject: [pure-silver] Re: under-developed?
It could be the difference with me and how I was taught. The D-76 was taught to me in a college class. There the only temp control was on the developer itself. But we also had a development chart for the various temps, and film types that was a good 20 years out of date. What ever the temp of the water coming out of the faucet was the stop, which varied widely depending on the season. The fix kept in 5 gal. containers was changed out maybe once a year. There were hundreds of rolls developed per week. We just got so we would fix longer to get rid of the pinkish color to our negs. It was there that I switched to HC-110 after taking a Bruce Barnbaum workshop. I also got my development times of digital truth froim that point on. The grain was significantly smaller, the contrast improved. No more weird things happening to my negs. I use dilution b unless like you the times get to close to 5 minutes. I like longer development times. I also started bringing my own fix to the school as well. I doubt the fix was the culprit in why I disliked D-76. I just was never able to control the contrast the way I wanted to with it. 

 Aggie
It sounds like the real difference was going to a controlled processing environment from one with quite uncertain materials and techniques. Contrast is a function of the degree of development. HC-110 and D-76 will produce nearly identical negatives when used correctly. There are small differences in the characteristic curves but they show up mostly at the very high density end. HC-110 is a very well designed developer, it performs well with many films, is long lived, and is relatively easy to use. However, its not the optimum developer for any film. By optimum I mean a developer which delivers highest speed, finest grain, best sharpness, etc. The differences will not be large but exist. HC-110 is also very versitile because it can be varied in strength to obtain convenient development times without affecting its other properties too much. D-76 was one of the first photographic developers worked out with any understanding of the chemistry of development. It was mainly the work of John G. Capstaff, of Kodak Research Labs. The formula was originally announced in a Kodak publication which also announced a new fine-grain film for duplicating motion picture negatives published in 1927. D-76 was found to be superior to the several formulas used up till then for development of camera negatives that it was rapidly adopted by the industry. It was soon discovered that D-76 had the peculiar property of increasing activity with time. This made predicting and controlling negative contrast difficult. The Labs worked on the problem and came up with an alternative formula for D-76 which included a buffer to maintain the pH constant. Current packaged D-76 follows this formula and is very stable in storage. D-76 became the benchmark developer and remains so because it delivers close to the maximum film speed, close to minimum grain and has other desirable characteristics. HC-110 was intended to provide a developer of similar characteristics in the form of a concentrate. Many developers devised in recent years make use of a developing agent (reducing agent to be correct) which was not available until about 1950. That is Phenidone. Although Phenidone is not listed in the MSDS for HC-110 it is the primary developing agent. Although many Phenidone containing developers deliver higher speed than conventional Metol-Hydroquinone types (like D-76) HC-110 is an exception. It delivers speeds comparable or slightly less than D-76. This is probably of no significance in actual practice although HC-110 is not a good "pushing" developer. If one is getting good results with HC-110 there is no reason to change to something else. The problem of measuring small amounts of concentrate can be handled in a couple of ways including making up a small amount of a lower concentration stock which is then further diluted for the working solution. 

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Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
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