Photo Engineer
Subscriber
Ryuji, the dye in question is a fine ortho sensitizing dye for all but AgBrI emulsions apparently. When placed on the AgBrI, the dye aggregates and shifts absorption max to longer wavelengths. The dye sensitizes in the red region when that happens.
Chemistry is available to prevent this, but I elected to avoid this route for simplicity sake and just switch dyes.
The effect with this dye was diagnosed long ago by one of Kodak's premier dye researchers. I discussed this with him on the phone and via e-mail just recently to confirm that I was indeed seeing the problem, ie a classic case of "J" aggregation.
The coatings using the dye on AgBr and AgCl are magenta in color, and the coating using AgBrI and this dye are cyan due to the aggregation. That is classically symptomatic of this type of aggregate and indicates red sensitivity.
I was spectrally sensitizing, doctoring and doping emulsions when you were in diapers Ryuji. Please consider this. I am also in the position of the young boy who lived near Albert Einstein and had Dr. Einstein help him with his math homework. When I have a problem that I cannot solve, I have friends who can help me and who know a lot more about the subject than I do.
Oh, and when I asked you for help finding a source for a better sensitzing dye and a better gelatin, did you give me one? No. When you asked me for my source of gelatin after I finally found a good one, I remember giving you name and telephone number.
And, as far as I know, Erythrosin does not form a "J" aggregate. I would have to check my notes, but the data I have says no. It has been used on AgBrI emulsions to impart ortho sensitivity, but it works best on AgCl. It is very touchy and difficult to use however, as we both know. Its main advantages are cost and availability.
PE
Chemistry is available to prevent this, but I elected to avoid this route for simplicity sake and just switch dyes.
The effect with this dye was diagnosed long ago by one of Kodak's premier dye researchers. I discussed this with him on the phone and via e-mail just recently to confirm that I was indeed seeing the problem, ie a classic case of "J" aggregation.
The coatings using the dye on AgBr and AgCl are magenta in color, and the coating using AgBrI and this dye are cyan due to the aggregation. That is classically symptomatic of this type of aggregate and indicates red sensitivity.
I was spectrally sensitizing, doctoring and doping emulsions when you were in diapers Ryuji. Please consider this. I am also in the position of the young boy who lived near Albert Einstein and had Dr. Einstein help him with his math homework. When I have a problem that I cannot solve, I have friends who can help me and who know a lot more about the subject than I do.
Oh, and when I asked you for help finding a source for a better sensitzing dye and a better gelatin, did you give me one? No. When you asked me for my source of gelatin after I finally found a good one, I remember giving you name and telephone number.
And, as far as I know, Erythrosin does not form a "J" aggregate. I would have to check my notes, but the data I have says no. It has been used on AgBrI emulsions to impart ortho sensitivity, but it works best on AgCl. It is very touchy and difficult to use however, as we both know. Its main advantages are cost and availability.
PE