I tried it with T-Max 400. The film was shot at ISO 200 for a contrasty subject. The Ultra Black was diluted 1:25. I tube processed for three minutes at 75 degrees. The negative came out very contrasty. I haven't printed it yet, but it looks about Grade 1 or 1 1/2 paper would work best.(posted 8467 days ago)Next time, I'm going to 1:50 and maybe 4 minutes.