My first time ... with ferri
To make a long story short I inadvertantly overexposed a lot of (the same) prints (people taking part in Round 14 of the postcard exchange - please avert your eyes!), probably a quarter stop, which made everything too 'sombre' (as the French say). I needed to lighten the entire print so I thought I would finally taking the bleaching plunge, mixed up some potassium ferricyanide (the only raw chemical I have) to make up a 10% stock solution, which I then further diluted to 1% for a working solution.
I put the prints in (one at a time) for 10 seconds before dumping them straight into the fix (forgot to wash before fixing, so I got a Farmer's effect, but no matter, the prints are exactly how I want them). Gave them a good wash, then dried them (this is RC paper). However, I noticed that there's a slight yellowing discoloration where white (clouds) meet black (sky), but not anywhere else -- that is, none of the other light tones display this yellowing. This bothered me so I rewashed, refixed, rewashed, and dried them again, but it's still the same. In the original print this is a light grey tone, now it's yellow. Overall it's not too distracting, but I'd like to know why this happened -- is it a result of my technique, or of the use of straight ferri (without redevelopment or toning), or something else. Also, other than esthetics, would it be damaging to the print? Is it worth it trying to tone the prints in something else (gold, selenium) to get rid of the yellow?
It depends a lot on which paper you use first. Yellowing can happen on some papers. Not with Ilford or Agfa.
Printing on RC why don't you do another print ?...
Ferry is more used for local bleaching.
Put the print out of the fix and spot ferry with a brush. As soon as the effect is close to what you want you rinse it with water. You need a hose on your left hand and the brush on your right hand... :-)
After that you fix and wash.
As the print "trop sombre", it wouldn't be THAT "sombre" in fiber as opposite to RC. Much more values et subtilites...
I know it's used for local bleaching but I didn't need a local bleach, I needed a global bleach for the entire print. I know I could just re-print, especially with RC, I'm just curious as to why it yellowed in the first place (so I can avoid it the next time). Again, the highlights are clean, it's just on the edges where they meet black that they've yellowed slightly.
It was on Ilford RC postcard paper, developed in PQ Universal.
ps. post 100 !
The effect might be too quick as the emulsion is very thin.
But I had that issue long time ago with Kentmere Art Classic who didn't like Ferry !
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I've found this with some papers - including Ilford Portfolio postcard paper. I solved it by using a much more dilute bleach (about 1/10 of the recommended). It takes a lot longer but makes it more controllable.
The yellow could be retained ferricyanide or other iron salts which can be removed with a bath of Disodiium EDTA and then a wash. OTOH, it could be a mix of ferric and ferrous oxide and hydroxide which require draconian methods to remove.
Oy...I just seem to compound one mistake after another. I guess that's a good way to learn what not to do. That was the last of my (new) postcard stock -- I think I may have to reprint on the older paper we have in the community darkroom for me to be happy. I'm not a great printer by any means, but I want what goes out to be the best I can do.
Bleeding. Bleeding from the black image area into the white
Originally Posted by mooseontheloose
area. Were the lights on during the processing? The very little
and now silver ferrocyanide and light sensitive took on
a yellowish hue. A minute amount of metallic silver.
I think Possible. Dan