E-72 Concentrate Update

Several months ago, I posted a thread about mixing E-72 paper developer in a concentrated form, leaving out the alkali (sodium carbonate). See my article in the Chemistry Recipes section for the formula, mixing, etc.

It's now been three months that the concentrate has been sitting in a partly-full brown plastic (not as good as glass, I know, but I had an empty one so used it) bottle. It has kept as well as I anticipated-- worked like a charm.

The ease, simplicity, low cost, and low toxicity of this formula is appealing to me quite apart from its excellent performance as a neutral tone developer that gives rich blacks and long scale. I like it a lot.

Larry

I'm curious why you picked E-72 rather than DS-14. E-72 is a rather crude adaptation of D-72 with no attempt to balance the formula after having replaced the two developing agents.

Probably because it has few ingredients, commonly available, and relatively non-toxic.

Good work Larry. I'm encouraged by your results.

Loose Gravel said:

Probably because it has few ingredients, commonly available, and relatively non-toxic.

Good work Larry. I'm encouraged by your results.

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I did try DS-14-- in fact have some mixed up. But you're exactly right about the reason for my experiment with E-72-- few ingredients, all commonly available, mostly at the grocery or health food store, non-toxic and CHEAP!

One other reason: because I already use Phenidone/Vitamin C for all my film developing, I was just curious to see if I could use the same developing agents successfully in a paper developer as well. The result is far fewer chemistry containers necessary on darkroom shelves.

I cannot tell the difference between prints developed in DS-14 and E-72. Both give a fairly neutral tone (particularly using Liquid Orthazite as the restrainer), both give good shadow depth and rich blacks, both have a long scale tonal range and similar contrast.

I'm an old enough dog at this game to have learned that complex and fancy is not necessarily better than simple when it comes to photochemistry.

Larry

Maine-iac said:

I did try DS-14-- in fact have some mixed up. But you're exactly right about the reason for my experiment with E-72-- few ingredients, all commonly available, mostly at the grocery or health food store, non-toxic and CHEAP!

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According to my costs spreadsheet, DS-14 is $0.56/liter, whereas E-72 is $0.33/liter, both working strength. I don't have your concentrate version in my spreadsheet. DS-14, though, is explicitly designed for use with a replenisher. I've not seen any instructions for replenishing E-72, and I don't know if it's practical or advisable. In practice, I tend to use a liter of working-strength E-72 for two or three dozen prints and then ditch it, so that works out to about $0.01/print. I replenish my DS-14, so I get many more prints per liter out of it -- probably at least 50-100, depending on how long I replenish before I finally ditch it. This brings the DS-14 cost down to $0.005 or less per liter -- half or less the cost of the E-72, given the ways I use the two developers. If I could replenish the E-72, that might change, but as I said, I don't know if this is practical.

Of course, both of these costs should be considered alongside other costs. Even $0.01/print for E-72 is much less than the cost of paper (roughly $0.25 to $0.50 per 8x10 sheet), for instance.

I cannot tell the difference between prints developed in DS-14 and E-72. Both give a fairly neutral tone (particularly using Liquid Orthazite as the restrainer), both give good shadow depth and rich blacks, both have a long scale tonal range and similar contrast.

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I do concur with this statement. I've recently begun collecting standard test prints from the same negative so I can do good comparisons. So far I've got prints from fresh DS-14 and fresh E-72 (made with metol rather than phenidone, though), and they seem quite similar. If it weren't for some minor blemishes on the E-72 print (unrelated to the developer), I don't know if I'd be able to tell them apart.