Rollei  ATP 1.1 in Spur and Moersch chemicals (May, 8, 2008)

You do not want to worry about color reproduction and white balance? You want maximum definition not restricted by Nyquist limits? Never heard of moire effects? Push your Leica lenses to the performance limit? You love to think about your photographs and you like to indulge in visual alchemy? Then you probably use film and low speed film mostly. 
There is something specially seducing about the picture coming out of the water, the image full of grain-free fine textural detail and with a tonal clarity that you will not see in digital imagery. 
The Rollei ATP 1.1 has been around for some time and now several new developers are being available. 
For this test I used the Spur Technospeed in its new commercial version as Rollei ATP DC, supplied in a bottle of 140 cc for the development of seven films. Also supplied in the package are seven small 20 cc bottles to keep the chemicals free of contamination by air. The film-developer combo is quite sensitive to speed and frequency of rotation (highlight blocking), so a careful procedure is required. The handling of the film is simplicity itself: develop for 6:30 minutes, fix for 1 minute, wash for three minutes and you can dry the film. Spur claims an EI setting of 40, high acutance and very fine grain. 
Moersch ATP flaTTec
This is another contender for development of this film. Here EI setting is 20, and fine grain, high definition are claimed. The chemicals are supplied in two separate bottles, concenrate A and B and the mix is 1:1.
Characteristic curves
below you will find the graphs of these film/developer combo’s. I also added the original Techpan in Technidol, with EI of 25. At EI = 40 the Spur developer did not reach the required densities and was a bit thin in the shadow areas. Optimum exposure setting is EI=25 to 32, but when deep shadow coverage is not required, or there are no deep shadows in the scene, then the setting of 40 is quite usable. For really good separation of deepest shadow tones, even EI=20 might be considered. This is of course part of the magic of black and white film: you can set the parameters to suit your particular needs or requirements. 

With optimum settings the curve resembles the original Techpan quite closely.
At EI=20 the Moersch developer is slightly less dense in the shadow areas and definitely less dense in the high lights. The overexposure latitude is very high. In fact you cannot bring the highlights to block. This is an ideal film/developer combination when you need to cover a very large luminance range: ten stops are easily available. You can just expose for the shadows and let the highlights care for themselves. The drawback is a low CI value, but you can compensate this with VC paper quite easily.
Definition and grain.
FlaTTec offers the finest grain, but in a slightly uneven distribution. Spur has a bit more grain, but the 400dpi can did not detect any grain structures, so for practical purposes both developers offer the same exceedingly fine grain. Definition with the Spur is higher than with flaTTec, not by very much, but Spur can record 90 more than lp/mm where the Moersch stops at 80 lp/mm. The inherently higher contrast of the Spur gives the image more clarity. Here the Spur improves on the original ATP developer, used in the previous test. The best feature of the Spur developer is indeed this high clarity of very fine detail, coupled with a virtual grain free image. With these characteristics, the Leica lenses are like fish in the water.
Left: Spur, right Moersch (very small selection from the whole negative)

Use of the film
Wide tonal range to cover a scene with extended contrast range on the one hand and clean definition of very fine detail on the other might be the short characteristic of both developers. Handling is easy, so there is no argument why you should not use both as needed. 
With current high speed lenses of superior wide open performance the low speed of the films is hardly a problem and might even be an advantage for picture composition as you can play with depth of field without losing definition on the critical plane of maximum sharpness. It is indeed most gratifying to load the MP with the ATP and the Summilux 50 ASPH at 1.4 and use this aperture for a whole day without a change in diaphragm opening. You will be amazed at the tonality and definition of the resulting pictures and the visual concentration on one clearly defined sharpness zone.