There is a basic model of color paper processor from Durst with 2 tanks which I assume does not use stop chemical for RA-4 processing. Fujimoto, however, makes one model with 3 tanks and I think stop chemical can be used in the second tank. My questions : 1)Is it OK not to use stop in RA-4 processing without comprising in quality? 2) Does any one has actual experience to share with in using these two models? I appreciate your advice in advance. Chen-Wah Lee