Mottled stains on prints?

[awldune]

Two of my prints (the last two) from yesterday's session have mottled stains, which I did not notice until today.

The stains are sort of blue-gray, but after putting a print in the fixer tray a little while the stain changed to a warm brown color but did not disappear.

Trying again with fresh fixer made no difference.

This is on RC paper, no stain on the back.

Any thoughts on what this could be?

[Valerie]

Possibly improper agitation during fix, or else the fix wasn't washed out well enough in the water. Happens to my students often when they are just learning. Don't let prints stack up on each other when washing them.. seems to be the culprit in the class.

[awldune]

Well, as it happens I didn't agitate those two much during fix and they were stacked up in the washer.

Guess that's the answer, thanks!

[Valerie]

Best of luck with the next printing session!

[sepiareverb]

Agitation in the fix is just as important as in the developer, but easy to forget because you don't see it working!

[awldune]

Was more careful to agitate the fix yesterday, and no repeat of the stains.

Not sure why I was thinking it would be OK to "stand fix"