Single bath fibre base paper fixing

[RalphLambrecht]

I personally test for both -

I test my process and I test certain prints.

RB

Of course, but why is Tom testing for residual fixer when he is trying to verify the validity of his fixing procedure?

 

[Tom Kershaw]

Ralph,

I should have clarified my terminology, yes, I've been testing for residual silver.

Tom

 

[dancqu]

VERY Dilute -- More Like 1:32

2 litres will evenly cover the 20x24" sheet?
I presume in terms of dilution we're in the
realm of 1+19 or so. Tom

I do not believe that the removal of the remaining
silver halides from film or paper is any other than
a quantitative reaction. That is, so much silver, so
much ammonium or sodium thiosulfate.

As Ralph and others have stated, do the tests. The
proof is on the paper. I test ahead each paper, worst
case; unexposed. The ST-1 and HT-2 drop tests must
show Zero stain if they are to meet my criteria.

Ilford states that 5ml of their rapid fixer will fix one
8x10; 200 8x10s per liter of concentrate. The dilution
I've mentioned allows for worst case + some. The
fixer is used at about half Ilford's stated capacity.

Agitation must be correct in order for the paper to
avail itself evenly to the fixer. My method stirs
the fixer. The paper is regularly pulled over
itself, front to back, right to left.

As you might expect washing is very easy.
The paper after fixing is Very little
loaded with chemistry. Dan

 

[rwboyer]

Of course, but why is Tom testing for residual fixer when he is trying to verify the validity of his fixing procedure?

I don't have a clue but I did mention that anyone that has questions about their process should probably test both. I did and it what is convinced me that the current process that I use (For the last 12 years) saves me time and money.

TF4 or 5 doesn't really matter - at film strength (the only recommended dilution) 1 minute for FB single bath 20-30 minute wash.

RB

Ps. Prior to this I was pretty convinced with Acid fixers in a more dilute solution that 2 bath HCA and wash was the only way to go.