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wildbillbugman
06-12-2012, 10:40 PM
I know that pinacyanol chloride is solubile in ethanol and in water. What about methanol ? Anyone know ?
Thanks,
Bill

Photo Engineer
06-13-2012, 08:37 AM
Bill, as a general rule, anything that dissolves in water or ethanol will dissolve in methanol.

PE

wildbillbugman
06-17-2012, 03:09 PM
OK, Here I go,
I will probably get my wrist slaped for my odd way of doing things, but here it is: I now use Sand's SDE3008,usualy green sensitizing dye, as a green and red sensitizing dye. I have been doing this by adding an excess of dye as the last component of an emulsion befor washing, except for surfactant and crosslinker which I add later . I add the dye at 200mg./M of AgNO3. I add the dye, mix at 25C for 15 minutes. I then precipitate the emulsion with IPA, . Then wash with many changes of water. I always get a great deal of red color coming out in the first two or three washings.
I have made and washed a small batch of emulsion in the same way using pinacyanol chloride instead of SDA3008. I used the same concentration and procedure as befor. This time I see no color at all coming off of the emulsion. Not even in the first wash. The dye is added as a 1% solution in MeOH, Just like with the SDE 3008. But the pincyanol chloride solution in MeOH is deep blue, whereas the SDE3008 solution is red-magenta. Both emulsions end up as a bright lavender color.
My reason for evaluating the pinacyanol chloride is that it costs only $70/gram. The SDE3008 now costs $600/gram.
I have not poured any plates yet.
Any insights?
Bill

Photo Engineer
06-17-2012, 06:18 PM
Well, the red color during the wash is the dye being washed away! The wash is almost always done before spectral sensitization to prevent this. Thus, without some proof, you don't know if you have spectral sensitizer present at a high enough concentration to give you any significant speed.

The lavender color to the emulsion suggests that there is enough SDE2008 present to give some red sensitivity, but the Pinacyanol may or may not be sensitizing. Probably it is.

PE

wildbillbugman
06-17-2012, 07:09 PM
Yes PE,
With the washed SDE3008 emulsion, shots of a Kodak Color Chart in daylight shows ballanced sensitivity to R,G&B. The reason That I wanted to try it this way, was to "optimize" the dye leval by it's bonding to the grain. Had I taken the other approach of carefuly increased aditions of dye to an unsensitized emulsion, my results would vary with every change in the flow of emulsification that affected grain size. This way, no matter the average grain size, there is a more or less constant leval of dye to Ag/halide. At least that was my way of thinking.
As I used an excess of SDE3008 ,prior to washing , it is no surprise to see red in the wash. What surprised me was the lack of color in the wash of emulsion sensitized with pinacyanol chloride.
Bill

Photo Engineer
06-17-2012, 07:43 PM
Bill;

I'm sorry that I did not address this in my book. It is highly unlikely that you get as even a deposition of dye on the grain if you add the dye before washing. It is actually more even and repeatable if you do it after washing, and at a fixed vAg.

However, if it works for you that is all that counts.

PE

wildbillbugman
06-18-2012, 10:59 AM
Thanks PE! Perhaps you will cover it in Volume II(Grin!). I have done the pigment-befor-washing many times now, with good consistency. Don't forget that none of these emulsions contain gelatin. They are made with silane functional PVA. This may acount for some differences between our observations. But I do waste alot of expensive dye doing it the way I do.
At least I am not one of those guys who just whine about the shrinking choice of film. I have not bought commercial film in years now. But I am still mad at Kodak for scraping Tech Pan! Like Kodachrome, Tech Pan will never be replaced!
I wonder if, say 200 years from now, people will be trying to duplicate the best of Kodak.
Bill

holmburgers
06-18-2012, 12:19 PM
I found this old thread where you guys discussed Pinacyanol salts.

http://www.apug.org/forums/forum205/66045-pinacyanol-salts.html

I'm very interested in pinacyanol chloride now; $70/gram for a red sensitizer; is this the route to an affordable panchromatic emulsion?

Coupled with erythrosine... I wonder how good it could get...

wildbillbugman
06-18-2012, 01:16 PM
Hi Homburgers,
Funy, I was just looking at that Thread yestesterday. It may be("hope springs eternal")that, just as SDE3008 green sensitizer acts as a red and green sensitizer, the Pinacyanol chloride may behave in a similar maner. My latest batches contain only SDA3008 green sensityzer and actualy are evenly sensitive to green and red. If not, there is always erythrosine.
Unfortuneately, Sands dose not release the dye structure, or even an absorbtion spectrum.
Bill

Photo Engineer
06-18-2012, 01:58 PM
Bill;

Lat time I looked, they had the spectra on line for most dyes, and had the structures listed for many of them.

PE

dwross
06-18-2012, 03:52 PM
I found this old thread where you guys discussed Pinacyanol salts.

http://www.apug.org/forums/forum205/66045-pinacyanol-salts.html

I'm very interested in pinacyanol chloride now; $70/gram for a red sensitizer; is this the route to an affordable panchromatic emulsion?

Coupled with erythrosine... I wonder how good it could get...

If all goes well I should have answers to the above in a week or two. I'm about to start in on pinacyanol Cl and pinaflavol experimentation. I am hopelessly corrupted by a scientific education, so I tend to be fairly structured and methodical about these things. My test tree for this one is particularly wide at the top (i.e. an end-product panchromatic emulsion might be a bit out, give or take luck) but I should know a lot more soon than I do today. I'll post on The Light Farm, of course, but also here if there is any interest. Bill and Jason are the only people I know who are actively working on emulsions right now.

************************************************** *******
Jason,

I'm starting from "X2Ag". If I get fog, I'll next try leaving off the gold sensitization step.
d

holmburgers
06-18-2012, 04:00 PM
Awesome Denise, looking forward to it. A scientific approach to this problem will be much lauded by yours truly. :D