diff --git a/README.md b/README.md index fdc9d5a..52e2083 100644 --- a/README.md +++ b/README.md @@ -684,6 +684,57 @@ avoid bromide artifacts on the bottom edge of the film. +### Update 8-5-2023: Super Dilute D-23 + +D-23 is easy to make and is often used when you need to control a +very long Subject Brightness Range. That's because it's a so-called +"compensating" developer that nicely reins in the highlights. + + **NOTE**: Ignore rumors you may have heard that D-23 is a "low + contrast" developer. It will deliver the contrast you want + based on how you work with it. + +I've gotten very good results with D-23 stock as well as 1:1 when doing +semistand and EMA development. But I wanted to push the dilution +envelope a bit. Why? D-23 is a "solvent" developer made of only +Metol and Sodium Sulfite. The Metol is the development agent +and the Sodium Sulfite acts as a preservative and produces the +required alkalinity for the developer to work properly. + +In normal dilutions, the Metol in it "chews away" at the grain. That's +the "solvent" effect. This helps keep the grain under control, but it +does so at the expense of absolute sharpness. + +By diluting beyond the recommended amount, we reduce the amount of +Metol in the working developer so there is less of that solvent effect +and the negative is rendered more sharply. + +Up to dilutions of about 1:4, I got consistently good results from +semistand with D-23. Beyond that, though, the reduction in the +amount of Sodium Sulfite in solution reduces its alkalinity to the +point that the developer stops working well. + +Someone on the UK Large Format forum suggested that I try D-23 at a +1:9 dilution but add 0.5 grams/liter of lye (Sodium Hydroxide) to the +mix to kick up the alkalinity. This works just great - you get super +sharp negatives with this scheme. HOWEVER, you won't want to do this +with smaller format/grainer films. For example, 35mm Kodak Double-X +done this way produced really grainy negatives reminiscent of highly +dilut Rodinol + +**WARNINIG**: Be careful handling lye. It will burn skin, cause + damage to eyes, and so on. As always, use sensible + lab techniques and wear protection in the darkroom. + Lye added to liquid is exothermic and can generate + a lot of heat, so be careful and take your time. + +For the record, I also tried this with DK-50 at 1:5 and got less +wonderful results. It certainly worked, but I didn't like how the +tonal range got handled. The negatives came out sharp but sort +of harsh looking. I think it may be that DK-50 has Hydroquinone +in it, but I'm not sure. I didn't test it as thoroughly as I did +D-23 so it might just be a lack of understanding on my part. + ## Copyright And Use All content here is Copyright (c) 2021-2023 TundraWare Inc., Des Plaines, IL USA