Yellow stain after fixing

[Michael Howard]

That looks a lot like tar from tobacco. Any smokers in the house?

 

[Ian C]

There is useful information regarding fixer use in the Ilford Rapid Fixer document. It advocates 2-bath fixing on page 3 column 1.

Read the information on page 4 beginning with the bold heading Silver Concentration and the following paragraphs to the bottom of the page (2nd column). In particular, read the information beginning with

“Prepare the testing solution by dissolving 2g of sodium sulphide in 125ml of water.”

https://www.ilfordphoto.com/amfile/file/download/file/1833/product/711/


From a Google search:

“Key points about yellow stains from rapid fixer:

Under-fixing:

The primary reason for yellow stains is not fixing the print long enough in the fixer, leaving silver halide crystals that can oxidize and turn yellow over time.

Insufficient washing:

Even with proper fixing time, inadequate rinsing after fixing can still leave behind fixer residue causing yellowing.

Old fixer:

Using old or overly diluted fixer can also lead to poor fixing and yellow stains.”

 

[Sirius Glass]

Hypo clear is superfluous on film. Film is not a fibrous base that requires an extensive wash. The gelatin emulsion as thin enough to get away with a very brief wash, just like RC paper.
Fixer is also definitely not known formally as 'hypo'. It's in fact an archaic term and was distinctly informal (as an abbreviation of 'hyposulfate of sodium') even when it was in regular use. It's also a misnomer for Ilford Rapid Fixer since that's evidently not 'hyposulfate of sodium'; the term 'hypo' was not originally associated with ammonium thiosulfate. The distinction is not just linguistic, but also practically relevant, since ammonium salts generally have much better mobility in solution and thus wash out more easily.

The use of HCA is not necessary on film. Even so, if HCA would do anything in this case, it would be a workaround for a deeper rooted problem that shouldn't exist in the first place.

Good to learn. Thank you.

 

[koraks]

You're welcome, and apologies for the pedantry.

 

[Rudeofus]

Under-fixing:

The primary reason for yellow stains is not fixing the print long enough in the fixer, leaving silver halide crystals that can oxidize and turn yellow over time.

This "yellow stain from incomplete fixing" is a profoundly different effect from what Alain Deloc reported. Alain's stain can be wiped off with a paper towel.

Insufficient washing:

Even with proper fixing time, inadequate rinsing after fixing can still leave behind fixer residue causing yellowing.

Alain's film is washed more than long enough. The "fixer residue causing yellowing" would do this weeks after drying, not right away.

Old fixer:

Using old or overly diluted fixer can also lead to poor fixing and yellow stains.”

Alain's fixer was mixed from fresh concentrate.

 

[MattKing]

FWIW, I read Sirius' reference to fixer as being "formally" known as hypo as either a typo or an error in diction.
The correct reference being instead: fixer was formerly known (colloquially) as hypo - from the relatively archaic sodium hypo sulfate.
Proof readers and pedants unite!!!

 

[koraks]

The correct reference being instead: fixer was formerly known (colloquially) as hypo - from the relatively archaic sodium hypo sulfate.

Yes, I considered this interpretation, but in the spirit of the truest and utmost pedantry, I decided to take it literally.