Precipitate in Fixer

[naren]

I tried to mix up some Kodak rapid fixer today... powder package to make 1 gal or 3.8 liters. The instructions said mix entire packet in 3 liters then add .8 liters to bottle at 72-78 degrees. I did make a mistake I guess by adding most of the packet to a 2 liter container, but that's what I was working with and I did use as hot H20 as I could get from the tap (didn't measure the temp though). It did cool down for a little while. I ended up getting this yellow precipitate in there. I mixed the rest into as hot water as I could get though and likewise added the last liter after running the tap. I also took half of that solution with the precipitate and mixed water with it in the jug, shook the hell out of it, placed it in a tub of hot water, repeated, repeated. Tried my best to get the damn stuff to dissolve but it wasn't happening.

My friend who runs the darkroom I work in says the precipitate won't be a problem but I kinda don't believe him. Some of it is too small to get rid of using a funnel with a sieve. I expect it could scratch the negs or something. Would love to hear peoples opinions on this. Trying to decide if I will donate the jug to the darkroom for fixing paper and buy a jug of liquid fix already made up. This sucks.

 

[Joao]

I had a bad experience with dried Ilford Rapid Fixer white residue accumulated on the treads & lid of the bottle it was kept in. Some of it was presumably falling into the tank and I was getting strange marks in my negatives; those marks disappeared from my negatives after I started removing that residue before using the fixer. It was certainly a very small amount of powder, but enough to ruin some frames. Now I am very suspicious about any solid partcles swimming inside my chemicals.
But your problem may be different: try and see what happens...
Joao

 

[delft]

Have you tried letting it settle and then carefully decanting? I don't think this is the first problem where mixing imperial and metric units are involved.

Dirk

 

[MartinP]

Ummm, the volume of water you used initially was probably not enough to completely dissolve the powder. Note, the term 'precipitate' means that a solid formed from a solution. Is that precisely what happened - or is this just the original powder which didn't dissolve ?

For mixing up developer stock solution in five litre batches, I use a cheap household bucket (reserved for developer-mixing only of course) so I'd suggest a similar thing for your mixing. Household 'hot' taps will be much, much hotter than the almost room-temperature you quoted, but I don't know if that would also cause problems.

What to do at this point ??

The solution that you have made can be checked by using it to clear an offcut of undeveloped film. That should look like transparent film base within a minute or so, if the fixer is working.

On a cautious just-in-case basis, any chemicals I mix from powder are always filtered immediately before use, with a funnel having a twist of cotton-wool pushed down the spout. It is surprising what gunge is collected from 'clear' solutions. This tip was given in the instructions of the first set of chemicals I ever made up from powder (for Agfachrome transparencies in the seventies) and I never saw any reason to stop doing it.

 

[dufffader]

I would try and separate the leftover solid from the liquid the best I can, but if its undissolved fixer I wouldn't be too worried. Snip and Dip the exposed end of your roll of negative, i.e. a test negative, into a small container. The plastic film container will do, and see if it clears up in a minute or two. If it does, then you're fine. Fix it for at least double the timing, say 4 mins etc.

 

[Al Kaplan]

If it does't disolve after a few hours run it through a coffee filter.

 

[Ronald M]

A layer of sterile cottom between two coffee filters will remove most all significant debris
from solutions.

You can also let it settle and syphon off the clear top liquid. Put it on a shelf and let it rest a day or so and syphon to a lower level without disturbing the bottle.

Use a thermometer and add powder slowly and keep stiring so as not to get clumps. The softer the water and fresher the chems, the less trouble you will have.