Fixer / film clear

[pstake]

Hi ... I have been processing my own film for almost a decade ... same for prints. I ordered some new fixer, Arista Odorless liquid concentrate. Did a search here to see what if anything people had to say about it, and I came across some interesting comments.

People were talking about how long it took their film to clear.

How do you know? I mean, how can you tell when the film is cleared? I have always just guessed conservatively that I had fixed the film long enough. If the negatives were especially important, I used fresh fix for 10 minutes, regardless of brand. For RC prints, 30 seconds; 2 minutes.

My question is: How can you tell how long it takes fixer to clear your negatives and/or prints?

 

[tkamiya]

For films, just stick in a clip of your film and watch it with a stop-watch in your hand. When it clears, the film becomes translucent. Sometimes, I save the leader (of the film) so I can test my fixer.

For prints, you can't do it visually and I honestly don't know how you'd measure the time to clear.

 

[pstake]

OOOHhhh ... hence "cleared."

Feeling a bit sheepish, now.

Thanks, tkamiya!

 

[MattKing]

With some films it can be a bit hard to tell when the film actually becomes translucent.

One way to deal with this is to drop a small drop on the scrap of film first and then set it down for a couple of minutes until you see a clear circle under the drop. Then put the scrap into the fixer and time how long it takes until you can no longer tell where the circle/drop was - that is your clearing time.

 

[pstake]

Thanks, Matt.

 

[RalphLambrecht]

this what i do:

 

[Doremus Scudder]

1. Determine clearing time in fresh fix as Matt describes above.
2. Fix for three times the clearing time (many say 2x, but 3x is recommended for films with higher silver iodide content and won't hurt any film). For optimum permanence use two-bath fixing; divide the total fixing time between two baths.
3. Use the clip test to test the clearing time before each batch of negatives/rolls of film. (Test bath 1 if using two-bath fixing.)
4. When the clearing time for a fixing bath reaches 2x that in fresh fix, discard it and mix a new bath. If you are using two-bath fixing, replace it with bath 2 and mix a new bath 2.

The clip-test procedure above is the most practical way of determining fixer exhaustion. More accurate than test solutions and capacity guidelines since it tests actual fixer activity.

Best,

Doremus

www.DoremusScudder.com