Edwal Hypo Check...Is It Snake-Oil?

<p>I read a post today on film fixing problems...purple, purple,

purple it was.<p>The suggestion of using Edwal Hypo Check for testing

fixer came up in the post.<p>I bought a bottle of that stuff plus the

darkroom I look after has had two more bottles donated to it.<p>Every

time I've tried any of the three bottles on used fix <i>or new

fix</i> the Fixer Check has gone milky...and milky Fixer Check

indicates bad fixer.<p>So my question: Has anyone actually used this

snake-oil successfully?<p><i>signed: Still Testing My Fix By Fixing

My Film Leaders</i>.

Oh-Oh...did I leave the italics open? Will this clo</i>se them?

We use it all the time with no problems.

Ann...so how does it work?

<p>Ooops...sorry lost the last half of that post...<p>So Ann how does it work. I know it goes cloudy in bad fix but does yours remain neutral in good fix? Are you using it with rapid fix? I just can not get it to do what it's advertised to do...<p><i>signed: Still Testing My Fix By Fixing My Film Leaders.</i>

i use it all the time at both school and home.

 

it works the same way at both locations (which rules out latitude, longitude, and elevation as possible factors).

 

it works like this:

 

put two drops in new fixer = see nothing.

 

put two drops in paper fixer tray after 8 hours of open lab = milky white.

 

 

basically the fixer agent is a mixture of two chemicals that combine in the presence of silver to form some milky white substance. when there is enough silver present in the fixer to act as a catalyst, the milky substance is formed.

 

my guess is that perhaps the solution in the bottles you have is contaminated or that the two chems in the mixture have combined somehow (heat maybe?)

 

put a few drops in pure water and see if it is white straight from the bottle. this will help you at least isolate the problem a little bit.

 

like i said, the hypo-check only checks for silver saturation, but there are plenty of other ways that fixer can go bad: developer contamination, dilution with stop bath/water or just too much exposure to the air can cause the fixer to "go flat". checking your film leader is still the most reliable thing you can do.

It's partly useful, partly snake oil.

 

I use it as a quick check to tell me when to start doing timed clearing tests. For example, with fixer used only on T-Max films Edwal Hypo Chek may start reading positive after only four or five rolls. I know from timed clearing tests the fixer is good for more than that.

 

Seems like the last time I used it to check paper fixer I got false positives when the fixer had hardly been used.

 

I dunno.

The instructions read that, in Rapid Fix, the hypocheck should be added, and then swirled slightly if cloudiness forms. If the cloudiness goes away after swirling (mixing), the rapid fix is still good. It has to do with chemical differences (primarily Sulphuric acid) between Rapid and regular fix.

 

As to whether it's snake-oil - I'm not certain of the chemical composition. 8^)

It's definitely not snake oil. If you have the same problems with three different bottles, and with several batches of fresh fix then it might be that you're not doing it quite right. In any case, we use it (at my local darkroom) regularly... except that we don't buy the Edwal stuff. 5g of Potassium iodide in 100ml of water... it's cheaper than buying it from Edwal.

I have used it for years with good results in testing. Your bottle may be a

defect. As far as your film goes, refix until clear so there are no problems later

down the road and then use Heico's Permawash. This should clear it nicely. It

soulds like your using TMX, if your using PXP, there is a little color to the

base...

Jim - what always concerned me: does milky mean my fix has reached half its capacity, 3/4 capacity or dump time?. signed: that's why we're both testing fixer with a film leader.

Andy's clarification may explain the behavior I see when using Hypo Chek on my rapid fixer. The drops become cloudy long before the fixer should have expired, yet dissipate quickly.

 

I don't have any traditional type fixer so I can't compare reactions.

Andy...I see where your coming from. So basically what we go on is that Edwal Hypo Check will work on non-rapid fix but not on rapid fix.<p>And Rick...very good point when you ask what does milky really mean.<p>Signed:<i> Still Testing My Fix By Fixing My Film Leaders</i>.

Jim, instead of using Edwal Hypo check or home brew with pot.iodide, why not use a small piece of unexposed film to test your fixer. The rule of thumb for fixing film is twice the time it takes to clear. If the test strip film doesn't clear in a few minutes(varies with emulsion) the fixer is exhausted or well or its way. I test my Ilford Rapid Fixer at film dilution (1+4) as described above. For RC paper dilution (1+9)I use a SWAG of double the time I use for film dilution to clear. I'm sure you'll get better ideas from others re testing paper fixer.

 

Les

Ooops! Sorry Jim, I didn't see your last post's sign off stating you're still using film leaders to test fixer. Now, I'm curious, is there a rule about using leader to test fixer at paper dilution?

 

Les

This is more appropiate for print fixer, because with film, it is quite easy to see it the film has cleared. As for printing, I have no problem with Hypo Check. But, fixer is CHEAP. When in doubt, throw it out! Using two fixing baths, I use 'used' fixer for the first bath and freshly mixed fixer for the second. After the 'maximum' number of prints (as stated on the fixer package) has run through the first (including the prints from the previous session), I mix another fresh bath and use the second bath as the first, and the fresh bath as the second. The Edwal works OK, but by the time it indicates that the fixer is exhausted, it's past time to dump it anyway.