Washing and concentrating emulsions

[Photo Engineer]

There are basically 3 types of UF units now being sold. They are "plate and frame", "spiral wound", and "hollow fibre". Kodak has used all 3 types. I will probably be trying all of them myself to decide which can be used for small scale emulsion makes in the 5 liter or less size, down to 100 ml.

I had some success yesterday, and hope to give more details soon.

PE

[Photo Engineer]

I have now determined that the optimum 'band pass' of any type of UF filter as noted above is between 10 and 100 K Daltons.

This is not my main field of work so I am learning and relearning stuff I never had learned previously or had only observed peripherally.

PE

[Neanderman]

I have now determined that the optimum 'band pass' of any type of UF filter as noted above is between 10 and 100 K Daltons.

PE:

Thanks for sharing all of this. I know it must be time consuming and not just a little expensive!

Ed

[Photo Engineer]

The street price for the average filter runs between $200 and $1000. You need a pump or pumps, tubing and lots of hot distilled water. You also need specialized cleaning and storage solutions.

PE

[Photo Engineer]

Bumping this up again.

I have a working UF system now that uses between 20KD and 50KD filters with low retention of emulsion. The system functions at 100F, 40C and 60 PSI for at least 1 hour with no failure. It uses a millipore plate and frame filter, and polycarbonate high pressure/temp tubing for output. All other lines are tygon. The pump is a diaphragm pump with seals and check valves to prevent chemical contamination.

The millipore filter must be cleaned with hot saturated Ammonium Bromide if it is to be re-used.

All fittings are plastic or stainless steel. The connections are all quick disconnect pressure fittings and they hold well at up to 100 PSI.

It is now being set up for resumption of the DVD taping sessions.

The total cost for such a system will be in the range of $1500 and is suitable for emulsions from 100 ml to about 1 liter with wash times running about 1 hour. It can concentrate an emulsion by up to 30% with a loss of about 15 ml of the original emulsion solution. The filters at $200 each will have to be replaced on a certain schedule of use which is TBD.

PE

[Kirk Keyes]

Cool - I look forward to the details!

[Neanderman]

Typically amazing stuff, PE. Very nice.

Ed