View Full Version : Hardener And Fogging

12-31-2009, 04:08 PM
Hi PE and All,
Please excuse me if this has been covered elsewhere:
I have done this so many times now that I know it is not a fluke or an hallucination. If I have fogging with an unhardened emulsion, I can add a bit of formalin and the fogging stops. I use formalin because it WORKS better than other hardeners. And I do not use much.

01-01-2010, 05:03 PM
Are you using formalin in gelatin-based emulsions, or gelatin substitute? Interesting outcome.
p.s. Happy New Year!!

01-01-2010, 05:55 PM
Hi Denise,
In fact, there has not been as much as a mg. of gelatin in any of my emulsions for at least 6 months.
I have been using a home-modified polymer. However, I think that my question is stll relevent for people who do use the animal generated stuff.

Photo Engineer
01-01-2010, 06:14 PM
Under normal conditions, Formalin can cause fog. It is a reducing agent that is known to cause "R" typing.

OTOH, it is such a powerful hardener that it retards swell and development and therefore you can lose speed, contrast and lower fog.

It is therefore a tossup as to which you see. Usually, Formalin requires long times to cause fog and speed increases, and that is why it is not used as a means of inducing higher speed through R typing. Usually, Formalin acts over several weeks to months to years, depending on level.

Now, that said, all of this is for gelatin alone.

IDK what your polymer is Bill, nor what the modifications are, and therefore I doubt that anything I say would apply to your conditions due to other reactions that might take place. Formalin is quite reactive and can release a host of byproducts when added to many materials.

EDIT: In an afterthought, I realized that in all the years of research at EK, Fuji and Ilford, no total substitute for gelatin has been found that will allow good crystals to be formed. Therefore, if you have Bill, I believe that it is patentable. You should get some Electron Microscope photos of the emulsion and some speed comparisons with gelatin for this and go for it!


01-02-2010, 03:40 PM
Thank you PE,
Thanks for your incouraging words. In fact, I have two other potentialy patentable chemical processes that are not related to emulsions. Whether or not I can afford a qualified patent attourny is another matter.
Where to find one who can hadel this type of invention is another matter. I am not KODAK, and do not have a Legat staff. But, if you have knowledge of an attourney who will talk to me, please send the info.

Photo Engineer
01-02-2010, 04:33 PM

The only patent attorneys I know work or worked for Kodak. As such, they are not inexpensive.


Dave Pritchard
01-02-2010, 05:58 PM
I have a few patents, and know some good patent attorneys. Send a PM if you are even half serious about this. I am willing to sign a non-disclosure before we talk.

01-02-2010, 06:54 PM
Thanks Dave,
I just sent the PM to you.