Transmar Hypo Tester

TRANSMAR HYPO TESTER

I have just seen a gadget on ebay with the name as shown above.

Basically a hydrometer with limited scale.

Never heard of anyone testing to see if their fixer is exhausted by using a hydrometer.
I have only heard of, and used the method of measuring the time taken for a piece of scrap film to clear.

So, my question is. Is this a genuine and reliable method of testing the fixer strength?

If it is a reliable method, what would be appropriate figures for good and bad fixer?

Chemistry is not a strong point with me. Is the theory correct?

I cannot find this device on eBay.

It is on ebay UK

Seller i.d. silverfoxx67

Item number 365835741264


Hope you find it now. I have never seen one before.

Simple devices - how deep they float tells you the Specific Gravity of the liquid. To be of use you need to know the S.G. of the solution you are measuring when fresh, and the S.G. when it is considered 'exhausted'. These values may vary depending on the fixer recipe in use. Since you are measuring a fluid, viscosity and temperature will have an effect.

They used to be used to test the state of battery acid, and are still used in brewing and other manufacturing. Most are calibrated for the task they are used for, though there are some that will do a range of S.G. They can be very accurate, but do you really need that level of accuracy?

Fixer is easy to track - count the films or prints though it, or use twice the clearing time for fresh fixer with film as your cut-off.

The Kodak publication CIS-61 is probably a good place to start, but I can't see it being much use for hobby levels of fixer use.