White Emulsions?

[wildbillbugman]

Hello Everyone,
Last night, after coating some glass plates by hand , I emptied my catch tray back into the beaker,closed it, then turned on the regular lights. I was surprised to see that the residual emulsion in the catch tray was brilliant white! I have never seen a white emulsion befor! All of the emulsions I have made are yellow. Of course, after about a minute the emulsion began to go grey. But it was totaly white to begin with. Has anyone seen a white emulsion ? My only test today was to establish that I do get an in-camera image indoors, with only window light. I intend to do more tests tomorrow.
Bill

 

[Photo Engineer]

Silver Chloride emulsions are white.

Silver Bromide emulsions are yellow.

Silver Iodide emulsions are orange.

Mixtures are in-between.

So, it depends on what you were making. Or did you make a mistake?

PE

 

[wildbillbugman]

Thanks P.E.,
It appears that I made a mistake! The first one ever.
This was supposed to be a silver bromide/iodide imulsion.
I wish I new what the mistake was. This one looks like the best emulsion I have ever made.
Bill

 

[Photo Engineer]

Well, check the speed. It should be slow and rather UV sensitive. It certainly will not be what you expected.

PE

 

[dyetransfer]

I got a fairly white emulsion with my matrix film emulsion before I started adding Pot. Iodine. The straight Ag Br emulsion is quite white, about one stop slower, with a depressed midtone curve. If this is your result, you may have forgotten the Pot. Iodine addition.

Regards - Jim

P.S. Have you gotten that monster Saltzman enlarger yet?

 

[totalamateur]

How funny, I thought my emulsions were always screwed up because they were yellow. I thought the were supposed to be white. Duh.

 

[wildbillbugman]

Hi All,
Sounds like Jim's explanation is the most likely.The emulsion is much slower than my previous emulsions. No Iodide would do that. I do not even have any sodium chloride (I surely did not use table salt) or potasium chloride.
Thanks,
Bill

 

[Photo Engineer]

That must be the answer then Bill.

However, to answer more fully, I looked at the spectra and data on pure chlorides and pure bromides and indeed the chlorides are white as they have most sensitivity in the UV. In fact, they are the inverse of UV colored.

Bromide emulsions are yellow. I guess the comparison comes from my having worked with both chlorides and bromides side-by-side and in a direct comparison, the bromides are distinctly yellowish. If you looked at a bromide alone, I guess you might call it white, whitish or pale yellow.

PE