• Welcome to Photrio!
    Registration is fast and free. Join today to unlock search, see fewer ads, and access all forum features.
    Click here to sign up

Red Sensitive Dye ?

Bill et al,

That wasn't me that asked about the color, but I always wondered about that. Many b/w films you buy are that purple-blue color. The ortho emulsion I plan to coat later this week is an ammonia digest AgBrI, with the I at 3%. Erythrosine was added to the AgNO3/NH4 before precipitation as advised by Glafkides. So, from what you are saying I ought to expect the emulsion to be that b/w film purple-blue color?

Poor weather is forecast for tomorrow so I will be in the darkroom setting up. I will probably mix some 2718. So this question comes up:

LIGHT SENTIVITY

Things I have read and the label on the dye bottle says the stains-all dye is sensitive to light. The bottle itself is opaque. When it says light sensitive, how sensitive are they talking about? Can I mix in room light (avoiding undue exposure) and just store in the dark or is this so sensitive I must work by safe light?

And if safe light would have to be used I guess it would have to be blue?

How is the SDA3057 mixed?

Any guidance appreciated!

-- Jason
 

Bill;

Without a good wedge spectrogram it will be difficult to evaluate the results unless you use Wratten separation filters for R/G/B. So, lets just wait.

The no Iodide emulsion may be too slow to register properly at the green wavelengths.

PE
 


Jason;

For starters, please be careful with both heat and light! I refrigerate all of my dyes at 4C.

Most all dyes can be handled for a short time in subdued tungsten light or a safelight.

Best of luck.

PE
 
Jason,
If erythrosine is your only dye, the emulsion would be sensitive to blue and green only. Therefor a RED light is called for. You would never use a blue light with any Ag/Br emulsion, with or without I. All of these emulsions are sensitive to blue. I am not familiar with the Stain All dye. But if it is truly panchromatiic, I would use a cheap($150) "Night Vision" monocle with an IR light source. Barring this, I would use a red light pointed away from your work area and as faint as you can handle.
SDA3057 - I mix a 1% solution in 100% methanol In a brown bottle and store it in the freezer. A dry dye in pure form should be able to withstand a brief exposure to light.
Bill
 
PE I use glass RGB separation filters(custom and pricy) for both testing and "real*photography. I normally photograph a KODAK color chart under full spectrum artificial light to shoot my test plates. With no filter, then each RGB filter.
Bill
 
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.

PE
 
You would never use a blue light with any Ag/Br emulsion
Click to expand...

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
Click to expand...

The problem is not necessarily finding the dyes, it is purchasing them.
 
Dye Mixing

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.
 
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.

PE
 
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.
Bill
 
You must log in or register to reply here.
Menu
Log in
Register