Boy, you scientist types sure can get Nasty! Do they teach that in your PhD program? I think I would rather go to art school.
- Jim
After over 3 years of this, I am becoming quite sensitized to this and annoyed. As I said elsewhere, I have only 2 choices; withdraw from APUG or take the abuse. I can face it and stop it of course but this is not looked on kindly by most as you indicate in your post. To just sit back and take the abuse is rather unpalatable and I think you would agree if you considered the matter by putting yourself in my place. Nevertheless, I agree with you in principle.
After thinking this over, I decided to mention that there is unpublished (AFAIK) work by Liang, Tong and Willis that prove that dye forms both a 'salt' with gelatin, but is also entrapped by the gelatin coils in the matrix of undenatured gelatin. The amount depends on swell or uncoiling of the gelatin matrix.
Thus, isoelectric point becomes less important in Dye Transfer and allows transfer of dyes in instant products at a pH of 12 or higher with bone gelatin. The gelatin holds two reservoirs of dye. In fact, in instant products the transfer of dye is continued from a pH of over 12 to one of about 4 simply by depleting this reservoir. A similar methodology may be inferred in DT products based on the ease with which Browning achieved a workable solution to this apparent problem.
PE
Ken;
I have made no personal attacks BTW, but have asked for proof of the claims of another person, or a retraction.
PE
Before you start posting anything you should have some repeatability. Anything done in scientific research requires that the experiment be repeatable.
Ron doesn't strike me as a sloppy researcher. I doubt he would have lasted long in Kodak if he was.Ron finds truth from highly amateurish experiments done by unqualified individuals and claims to understand how they work from them. He infers facts about physical and chemical properties from these sloppy amateurish experiments that are poorly documented, poorly tested and poorly researched.
The work of those I cite regarding the dye - gelatin interactions dates from the 1980s, and for all I know is unpublished. This is far more modern work than that from 1942. There was a lot of understanding of gelatin - dye interactions in the intervening years during development of instant imaging in order to understand dye migration. I have read much more modern work internally at Kodak and fully understand it. It indicates that path length (swell) is as important as any effect of isoelectric point, and indicates that the coiling of gelatin is important in determining path length.
In any event, the fact that print density might change with isoelectric point is immaterial in this case with Jim's coatings, as they work perfectly well. And, that seems to be what the argument of isoelectric point is all about. Jim has something that works and another person is arguing that it isn't a good solution. IDK how that can be argued in the face of success.
PE
While I certainly don't want to further inflame a potentially nasty thread, I would like to say this;
I deeply respect Ron for his work and the fact he is prepared to share his knowledge. I am evidently not alone in this view.
He is obviously very knowledgeable on the subject of emulsion making and coating.
Mgarelick; As Bob M has already stated, we would be interested to see your work. If you are able, please post some examples.
Likewise, if you can prove Ron is not who he says he is, I'd like to know about it. I expect more stony silence on this point... Ron has never struck me as being a liar, either in public or private conversation.
May I point you in the direction of Denise Ross, who is using one of Ron's formulas? She is getting good repeatable results: DWR Photos - Emulsion Research
As an aside, I'm not overly impressed by your unprofessional approach to the forum. It is comprised heavily of amateurs, who resent having mud slung at them -
Ron doesn't strike me as a sloppy researcher. I doubt he would have lasted long in Kodak if he was.
In addition, nearly all of the early researchers in photography were amateurs. They got results. Why shouldn't modern day amateurs do likewise?
Why pull someone's work apart when they are getting good results? Jim Browning has a very workable film with which he can feed his (and others') interest and practise his craft. Put in context, does it really matter if it doesn't precisely emulate Kodak's material? - "If it ain't broke, don't fix it" comes to mind.
Unfortunately, your explanation is offset in part by the increase in size of the molecule. The size increase will slow down dye diffusion but as you also see effects from charge. Models attempt to separate out these effects. In the end, Isoelectric point is less important in some cases than the path length and size of the molecule. A cyan dye with 3 azo groups and one sulfonate can diffuse more slowly than one with 2 azo groups and two or three sulfonates. Of course 3 or 2 azo groups can both yield cyans, and two or one azo groups can give magentas with the right side groups. This further confounds the picture as does the localized charges in the molecules due to side groups.
This is a very complex intersection of materials science and organic chemistry that can often only be solved by empirical experiments in some cases.
A big fat Guaiazulene dye will be very difficult to diffuse but may give an excellent cyan or magenta depending on pH. It is path length and coil size of the gelatin that can overwhelm the effects of isoelectric point, but then selection of other dyes tilt it the other way. This fused ring type of dye structure completely offsets some predictions.
The bottom line is the resultant print though and not these discussions.
There were many solutions to the problems presented by Dye Transfer and Kodak selected the most economical. There were others that might have been better and others that were 'don't care' situations. This is important here as well and cannot be ignored!
Jim Browning's method works nearly perfectly but is somewhat different than Kodak's method. This is an example of an empirical solution optimized for result rather than economy or production I would suspect.
PE
I should also note that I am receiving word that people are in fact disagreeing with Ron's position on this forum. I would strongly urge others to post if you do disagree with Ron and why. I'm not suggesting an attack; just let us know what you find wrong with Ron's approach to this topic.
....I finally ended up using Matrix film, painting it and using modeling dye and then transferring that to DT paper. More fun to me.
PE
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