New emulsion maker questions: chemical keeping properties and availability

[Nodda Duma]

I use a 10ml syringe to apply my emulsion to plates. Works fine for 5"x4" and 5"x7" plates. Make sure the emulsion is at temperature before coating (114F for me).

As a consequence of my work schedule, I've had to store emulsion for several months (stored in sanitized cheese crocks in my beer fridge) before pouring. I mixed the most recent batch in July, and when tested the emulsion at the time was ~ISO 0.5. Last weekend I coated several plates with this batch -- which coated just fine -- and will be testing sensitivity soon. Before heating to coat, I inspected the surface of the undried emulsion for degradation (mold, whatever) but did not notice any issues.

Last time I coated emulsion after storing several months, the emulsion would flake away under development. However, that batch had other issues related to adding too much water. This batch came out very well.

 

[Photo Engineer]

Indeed, the spots are pepper grain. This is due to poor mixing. It also takes place with the AgBr emulsion and will take place with scale up emulsions at about 400 ml if you don't use even better stirring and thicker walled beakers to retain heat.

PE

 

[Nodda Duma]

addendum to my post above: Success! The emulsion is fine after several months of cold storage in sanitized cheese crocks: No odd behavior during development. The test plates are drying now and appear to be fine. I tested for ISO speed and it is running ~ ISO 0.3 - 0.5. I'll capture another test image and post a summary in a separate thread.

 

[Photo Engineer]

Note that speed of AgCl is greater outdoors than expected if the lens used is uncoated. Most of the sensitivity is in the UV region.

PE