View Full Version : Red Sensitive Dye ?
11-27-2013, 10:54 AM
I’ve no clue about emulsion making and sensitizing. However I found this webpage with a catalogue of dyes:
Perhaps it helps you. Some are marked as sensitizer in the specifications:
For example CAS 52749-17-4 is maked as „Red sensitizer in photography“:
which is quite affordable at Sigma:
11-27-2013, 01:55 PM
The most common dyes are cyanines, carbocyanines and merocyanines. There are others, but these, being fairly common, may be easier to obtain. I posted the suggested EK list earlier in another thread. These are still made by a division of Eastman Organics or Sigma Aldrich.
11-27-2013, 02:45 PM
You would never use a blue light with any Ag/Br emulsion
No, I meant a blue light just for the dye! But, it sounds like the dye sensitivity to light isn't that much of a concern.
However I found this webpage with a catalogue of dyes
The problem is not necessarily finding the dyes, it is purchasing them.
11-27-2013, 08:56 PM
So, tonight I made the 1% solution of the Eastman 2718 dye in ethanol. Since I did not know what to expect, I thought I would leave my notes here for others who might wonder as well.
The dye itself is very fine dark olive-green power. Think army green but about two shades darker. It cakes easily and sticks to everything.
Once mixed with ethanol it makes an intensely purple colored solution, almost florescent.
My mixing was done by putting a small clean funnel into the dropper bottle I'm using sat on my Ohaus balance and using the handle of a plastic spoon to add the 250mg dye. (Zero the weight of the bottle and funnel, add 250mg and carefully add dye till zero'ed again.) The dye clogs in the funnel but a few solid raps on the bench top got almost all of it through. Then used 25ml of ethanol to wash the rest through the funnel.
Any spillage can be easily cleaned up with water. Interestingly the dye turns grey in contact with water.
11-27-2013, 11:13 PM
The key test is the color the emulsion takes on after adding the dye.
An AgBrI is yellow, with the intensity varying based on dye quantity and Iodide content. A red sensitizer is cyan so the emulsion will be yellow + cyan.
11-28-2013, 12:48 PM
Happy Thanksgiving PE,
SDA3057 IS RED. When added to an AgBr emulsion, the emulsion is magenta. Add Iodine and the emulsion turns bright lavender-cyan. My emulsions tend to be closer to white than to yellow, before addition of dye.
BTW, my last emulsion turned out to be far faster than I anticipated. I got only one panel, exposed at 1 second / f16 that was readable. I need to do the whole thing over. The panels were not fogged, as evidenced by unexposed areas showing no development.