Developer concentrationgreenspun.com : LUSENET : Black_and_White_Photography : One Thread
I am curious about the differences in developing films such as T-Max, (TMX, TMY, and TMZ) in developers such as T-Max Developer. What is the difference between developing negatives at concentrations of 1:4 versus 1:7 using the published recommended times? Certainly you save money by using the 1:7 and longer developing time. Are the film curves relatively the same?
-- Anonymous, July 24, 1997
I don't use T-MAX developer, but I can tell you something about the reason to use (or not to use) diluted developer.
It is true that the use of diluted developer can bring to some economies (even if the replenishable developers normally turn to one-shot developers when diluted), but this is usually not the main reason to choose that kind of process.
In fact, the use of a diluted developers changes (sometimes dramatically) image qualities. Dilution affects the ENERGY of the developer: the action is slower and the ratio in darkening speed of highlights and shadows is modified.
A diluted developer, when compared to its non-diluted counterpart, brings to higher separation in the shadows and tends to avoid blocking-up in the highlights.
Because of the lower developer's energy, the highlights develop slower than normal; moreover, in the darker part of the negative, the developer tends to be exhausted by the large amount of bromide that converts to metallic silver.
On the contrary, the increased developing time allows better development in the shadows, that tend to retain more details.
So, the use of diluted developer is specially indicated in treating images with a great exposure difference between shadows and higlights. In example, if you shoot in a dark church, the use of diluted developer can help you to achieve good control of the highlights (tipically the stained-glass windows, or the candle's flames) without sacrificing shadow detail, thanks to the slightly compensating action.
By the way, you can increase the compensating action by reducing the agitation during the development: in this case, in fact, the effects due to the exhaustion of the developer are increased.
On the contrary, if you are processing negs coming from "flat" subjects, the use of diluted developer is - generally speaking - to be avoided.
I greatly appreciate the overall effect granted by the use of diluted developer: my "standard" process for T-MAX (TMX and TMY) is now based on XTOL in 1+2 dilution.
-- Anonymous, July 25, 1997