View Full Version : D-76 Dilutions and Effects

jonathan smith
18-Jul-2004, 17:59
I wonder if anyone has been using D-76 at 1:3 dilution and, if so, what are the effects and also a general guide for extra time?

I have settled on a processing method that requires 1/2 gallon of solution. Right now I use stock, and add time for subsequent sheets. But I would like to mix up just enough for two sheets and not have to worry about the age of the solution. I want to mix it up fresh and then dump it, and that would mean a 1:3 dilution to reach 64 oz.

So, is anyone using D-76 1:3 Aside from the mechanics of it, is there a quality difference?


N Dhananjay
18-Jul-2004, 22:24
You would need a longer time to reach the same contrast. Other than that, at 1:3, D-76 would give you increased sharpness and slightly enhanced grain - there might be a teeny drop in speed, although I doubt you would notice that. The reason for this is that when you use D-76 undiluted, it is essentially a solvent developer. There is sufficient sulfite in the developer to etch the grains before development. This reduces the graininess but also reduces sharpness because the grain has a core sorrounded by a slightly diffused edge. When you dilute the developer, there is no longer enough sulfite to initiate solvent effects. Thus, graininess increases and so does sharpness and edge effects. Cheers, DJ

John Cook
19-Jul-2004, 04:06
DJ has pretty well nailed it.

I worked in a commercial product studio in 1970 where D76 at 1:3 was the standard formula. As I recall, there was a modest increase in grain and sharpness. You had to really examine a print to see the improvement in sharpness. The grain, while slightly increased, was nothing even remotely like that produced by Rodinal.

Development time increase was also modest. In the area of 25 to 50 percent at most. Didn't notice any decrease in film speed.

Bruce Watson
19-Jul-2004, 06:43
Slightly increased grain and sharpness, as the others have said.

The rule of thumb for dilution and developer time is that time increases as the square root of dilution. This is true for continuous agitation. Clearly, as you get farther away from continuous agitation, this has less and less meaning, until you get to stand development where development time is just "long" however you want to define it.

In your case, as you move from straight D76 to D76 1:3, your time would double (sqrt (4)) to reach the same contrast index under continuous agitation. Clearly, you'll have to experiement some to find out what really works for your process. All this rule of thumb is for is a starting point.

Jacques Augustowski
19-Jul-2004, 08:05
Jonathan, I have been using D-76 dilution 1:2 for at least 6 years with TRI-X 35mm film. The EI for this film/developer is 200 and I use a condenser enlarger. The developing time is between 8 and 9 minutes @ 20C depending on the contrast range of the scene. I have developed TRI-X up to 26 C with no ill effect. this is the best developer/film combination I have ever had, accutance and sharpness is fantastic and the high value tones has a great separation. This is a cheap developer to buy or make. I donīt use this developer for large format because I do alternative printing, were my density range is above 1.6 Jacques

Chris Gittins
19-Jul-2004, 18:18

My standard combo is HP5 with D76, 1+3, 68 deg F. I'm on the road for work at present and don't have access to my test data, but if memory serves 11 minutes development yields CI = 0.40, which works out to be N for how I print. CI changes by 0.020 per minute and I do 9 minutes for N-2 scenes.

I haven't done enough with 1+1 or 1+2 to provide a detailed comparison. (1+3 was what we used in a Zone System class I took a few years back and I've just stuck with it.) That said, I've never printed my 4x5 negs larger than 11x14 and I couldn't see a difference between prints from negs developed in 1+2 vs negs developed in 1+3.

If you're interested in film curves for HP5 in 1+3, send me an e-mail and I'll forward those to you when I get back from my trip.


jonathan smith
21-Jul-2004, 03:13
Thanks everybody,

Great information; I'll do some testing at 1.5x and 2x processing time. I'll be contact printing (8x10) so I don't think grain will be an issue, and I do like the idea of increased edge sharpness.

Thanks again,