A. Thio At 1:49 - Strength and Speed
I've finished a short series of fixer tests. I've tested only
Arista 5x7 grade 2, RC. The solution volume of 125ml included
2.5ml of P's Formulary ammonium thiosulfate and nothing else.
The pre-wet but unexposed sheet was given 2 minutes of
constant agitation. Three washes, 1, 2, and 3 minutes,
each of 125ml distilled, followed.
I could see no trace of stain using the ST-1 test.
Completely clean and in two minutes; A. Thio. At 1:49. Dan
Are you planning to test the capacity of the fixer? A 1+49 dilution has a lot less "active ingredient" than Ilford's recommended 1+4 dilution for rapid print processing.
It would be interesting to use that same 125 ml and continue to process 5x7 sheets while plotting the elevating silver content, perhaps by using Kodak silver test papers. This would give us some idea of the square inch/per ml capacity of fixer.
My capacity of a liter of concentrate at 1:49 is twice that of
Originally Posted by Reinhold
Ilford's at 1:9 dilution which is twice that of Ilford's at 1:4. At
my 1:49 dilution a liter of concentrate will fix well within
Ilford's archival limit, 200 8x10s. That is based upon
a silver content of 1.6 grams/meter square.
At Ilford's 1:9 that same liter will fix 100 and at 1:4, 50. The
higher concentrations likely will fix less archivaly or not at all.
Ilford's maximum silver content per liter working strength, .5
gram, is based upon an average mix of prints. My standard
is based upon an unexposed sheet of print paper.
According to my standard 5ml of concentrate in 250 ml of
solution, 1:49 dilution, will fix ONE 8x10. AND do it in
TWO, 2, MINUTES.