yellow staining

[Nicholas Lindan]

why would it only be on one edge? Thank you

I have no idea - just throwing out a speculative question: is the roll ever held vertically so the liquid would migrate to the one edge?

 

[Kirk Keyes]

Acidic developers [Ansco 130] use water as a stop bath.

Ansco 130 = acidic.

What? With all that sodium carbonate in it, it most certainly will be basic, not acidic.

 

[Kirk Keyes]

PE has posted on this a number of times.

Fixers, including alkaline fixers, are designed assuming that acid stop-bath will be used.

This needs repeated. PE has pointed out that TF-4 is buffered and can handle an acidic stop. And remember, you should let the print hang over the stop bath tray and let the excess stop on the surface of the print drain off the print.

If you are really concerned about the TF-4, then try another fix, like Ilford Hypam or Kodak Rapid Fix and then you don't have to fret over such things.

 

[dancqu]

[QUOTES=Nicholas Lindan;849424]
"I think it appears that way because prints are
almost always developed to completion."

Appearances count.

The 10 and 30 second Kodak and Ilford quick dips are
no quicker at washing out the developer than same time
dips in H2O. The acid dips do though impart an overall
acidic character to the paper making them compatible
with the acid fix. More important in the days of the
ubiquitous fix with hardener.

"Water-bath development for contrast control is an
example where water doesn't stop the development."

Water bath technique calls for little or no agitation in
the water bath. So the slow stop. Several cycles are
usual; back and forth then back and forth then ... .

"As I understand it an acid stop halts development so
the developer doesn't hit a silver-laden fix in an
active state."

So too with a water stop. As the print developer is
diluted it's ph is plummeting. Much diluted and with
a ph nearing 7 the developer's activity nears zero.

"Two bath developers like Diafine work on the
principle that a lot of developing agent is carried
in the emulsion and it takes a good bit of time
for it to diffuse out."

Once again little or no agitation. Also, the
second B bath is quite alkaline. More so
than than TF-4. Dan

 

[bjames]

"I have no idea - just throwing out a speculative question: is the roll ever held vertically so the liquid would migrate to the one edge?"

Thanks Nicholas, thats a great observation, yes we do tilt it to one end to drain. Im not sure what it means but if thats the edge which also fogs that would be very telling. I will have to pay attention to that specifically next week.

 

[George Collier]

About the acid stop with TF4 -
The first time I used TF4, it was with Pyrocat HD and, I think, FP4, 2 1/4. I forgot about the recommended water stop and used a very weak acetic acid stop (something like a drop or two in 500cc water). I saw some strange artifacts in uniform areas of the negative (like sky areas) and called Formulary about it (I thought at the time that it was the Pyrocat). I was told in no uncertain terms that any acid in the stop was not good for the TF4. I replaced the fix, have adhered to the water only stop bath advice (I use a minute of running water in a tray for fiber prints - after a 15 second dip in a deep tray of water), and had no problems since.
I hear what some of you experts are saying about the buffering of TF4, and recently, as described in a thread I put out a few weeks ago, I too, had some yellow edges in 16x20 Ilford MG IV VC, first time ever.
What goes?