FX-55 is Geoffrey Crawley's new ascorbate developer. I mention it because it appears to give a rather special tonality. Mine was made up in propylene glycol using excess potassium carbonate,as suggested by Patrick Gainer: www.apug.org/forums/forum37/53995-new-fx-55-developer.html If preferred the part B can be made up just before use as Crawley suggested. I develop for double (2x) the Xtol 1+1 times at www.digitaltruth.com/devchart.html My agitation is 30s start then 2 inversions on each minute.This is about 50% longer than Crawley's times,he agitates every 15 sec. On the attachment I have plotted the curves for Delta 100 in FX-55 (from Crawley's AP article) and in ID-11 (similar to D-76, from Ilford's data). The curves suggest a higher contrast for FX-55 in the lower mid tones. I made prints from negatives of the same scene in different developers.FX-55 gave somewhat higher mid-tone contrast than Xtol 1+3, more than PC-TEA and a lot more than D-76 1+1.As its pH is only about 8 FX-55 gives fine grain although with low sulfite it is an acutance developer not a solvent developer. Anyhow this first rather unscientific tests suggests FX-55 has potential for interesting tonality.