Rapid Fixer -- 1+3 vs 1+4

[bvy]

Another fixer thread from me -- sorry.

Some time back I dedicated a 600ml bottle to fixer. I marked a fill line for stock fixer, topped off with water, and stirred.

The other day I noticed that this fill line is based on 1+3 and not 1+4 (150ml instead of 120ml). So I've been fixing my film at 1+3 for who knows how long.

So what's the risk? Some time back I had a mysterious problem with emulsion flaking in Acros and wonder if this could have been the culprit.

Thanks.

 

[pentaxuser]

I am not a chemist so can't give an expert opinion but based on the difference of 30ml of stock fixer I'd be surprised if this is the cause of any problems. I know this may be a flawed comparison as this example is paper but I have seen some users stating that they fix paper at 1+4 instead of the usual 1+9 so proportionally a much greater increase in concentration and I have never seen reports of problems.

pentaxuser

 

[MattKing]

IIRC, several years ago Simon Galley addressed the change in dilution instructions for Ilford Rapid fix.
For a long time, the instructions said 1 + 3. They then changed the instructions to say 1 + 4, and even went to the effort of pasting new labels over their existing stock of bottles to reflect that change.
The reason for the change? They determined the 1 + 4 dilution worked just as well, and the additional economy made it easier to sell the fixer.

 

[Doremus Scudder]

Ilford Rapid Fixer and Hypam indicate a 1+4 dilution for film. Kodak Rapid Fix dilutes 1:3 (1+3). Other brands are one or the other usually. Do read the mixing instructions

As for using fixer too strong: a 1+3 dilution for the Ilford products probably will make little difference (you did do the clearing test, right ). However using rapid fixers too strong actually decreases their ability to fix; there has to be enough water in the mix to make things work correctly.

Best,

Doremus

 

[bvy]

IIRC, several years ago Simon Galley addressed the change in dilution instructions for Ilford Rapid fix.
For a long time, the instructions said 1 + 3. They then changed the instructions to say 1 + 4, and even went to the effort of pasting new labels over their existing stock of bottles to reflect that change.
The reason for the change? They determined the 1 + 4 dilution worked just as well, and the additional economy made it easier to sell the fixer.

Well they're not going to sell more fixer that way (!). But good for them and good for us. And good for the environment too...

I wonder how long ago they changed from 1+3, and if it could be that I based my measuring on those old instructions.

 

[MattKing]

Well they're not going to sell more fixer that way (!). But good for them and good for us. And good for the environment too...

I wonder how long ago they changed from 1+3, and if it could be that I based my measuring on those old instructions.

If you follow the instructions and re-use your film fixer and monitor its response using a clip test, a batch of 1 + 4 fixer will give you less yield than a batch of 1 + 3 fixer. Essentially, the bottle of concentrate should fix approximately the same amount of film, whether you use 1 + 3 or 1 + 4.
As for the time of the change, I would guess something like 2005, because I recall from around then having a couple of bottles with both the new label (on top) and the old label (underneath).