As mentioned in a number of previous posts, i have been conducting a number of film developer comparisons just out my own interest. For years i have used Kodak's TMAX developer and i have loved the results I've got but i decided to test Ilford's Ilfotec DD-X developer to see if Ilford chemical produced better results with Ilford film than the Kodak.
Both chemicals are priced the same at £11.99 from Jessops photo retailer. The TMAX developer is more economical to use developing up to 12 rolls per mix compared to Ilford's two film recommendation for the DD-X. That said, a DD-X 1-4 mixture can be used several times with increases in developing time if you want to be more economical. I used a single mixture to develop four rolls of FP4 with no problems - the second set of two films had 10% added to the standard 10 minute dev time. I wouldn't use the DD-X mixture to develop more than four or six rolls of film but that is just a personal preference as the developing times start to stretch out considerably.
The most important thing for me was the results of the processing and happily i was extremely impressed by the DD-X's results. Negative tone, contrast/sharpness and grain were excellent - in some cases better than the TMAX but not excessively so. For me the DD-X provides slightly better grain and tone results when developing PAN F, FP4 and HP5 than the TMAX does but again the difference is negligible. Overall i was immensely pleased with the DD-X results finding them very similar to the TMAX but with slightly less grain.
In conclusion i would say that the Ilford developer is certainly a match for the Kodak TMAX developer. I started using TMAX in 1991 and its been an important part of my black and white processing since then. You don't make changes very lightly when you have used something for that long but I'm so pleased with the DD-X that it has become part of my official developing arsenal.
The only recommendation i can make is to try them both if you use a broad range of film speeds and then make a decision between the two chemicals. If you only use film speeds of below 125asa i would recommend the DD-X as the developer of choice. The results are just superb!