PDA

View Full Version : erythrosin & eosin



Pages : [1] 2

JOSarff
02-01-2011, 01:06 PM
erythrosin CAS 16423-68-0
eosin Y CAS 17372-87-1

would these be correct as sensitizing dyes for a basic emulsion formula?

Thanks a lot.

Joe

Photo Engineer
02-01-2011, 01:36 PM
Joe;

Erythrosine is the better known of the two for having activity as a sensitizing dye for emulsions. The wedge spectrograms of Green sensitive Azo type paper was done with Erythrosine. It is a common food coloring and is an active ingredient in Merthiolate. It is easily purchased at a rather low price. My last batch came fro www.kyantec.com

PE

Marco B
02-01-2011, 02:03 PM
Joe;

Erythrosine is the better known of the two for having activity as a sensitizing dye for emulsions. The wedge spectrograms of Green sensitive Azo type paper was done with Erythrosine. It is a common food coloring and is an active ingredient in Merthiolate. It is easily purchased at a rather low price. My last batch came fro www.kyantec.com (http://www.kyantec.com)

PE

Interesting, I know these substances as colouring dyes for microscopy. I never realized they had a function as sensitizing dyes. I love these parallels.

winger
02-01-2011, 04:27 PM
Interesting, I know these substances as colouring dyes for microscopy. I never realized they had a function as sensitizing dyes. I love these parallels.

Same here!

Photo Engineer
02-01-2011, 04:34 PM
What is not as well known, is that in spite of the many publications of the Agfa paper formulas such as Brovira is the fact that Brovira used Erythrosine. The reason it is missed is that the dye was applied, along with about a half dozen other "missed" ingredients, in an overcoat. Thus, Brovira was Ortho-sensitive.

PE

Photo Engineer
02-01-2011, 10:09 PM
So much for relying on memory.

After searching several sources I find that Agfa used a green sensitizer for several of its paper products. Some used Erythrosine and some used a dye which as I reported before is unknown (hier ist unbekannt) and they also used a method of applying the dye(s) either in overcoats or added to the emulsion just before coating. It is not clear regarding this either. In any event, at least two dyes were used in Agfa papers and up to two methods were used to incorporate them.

Sorry for the lack of clarity in the last post. I was working from memory. Now I have notes, such as they are.

PE

hrst
02-02-2011, 01:09 AM
Did I understand you correctly, are you referring that some sensitizing dyes were added in overcoats? Is it possible that they work there as sensitizers? AFAIK the dye must adhere to the silver halide to pump energy in it in order to work. Is this possible from overcoat?

Thanks.

Photo Engineer
02-02-2011, 08:18 AM
There is some indication that dyes were added in overcoats.

It is known that early dyed coatings were coated first and then dipped into a solution of the dye. The emulsion was sensitized by this dip/soak treatment, so why would an overcoat not work?

The German wording is unclear. They use a word which my dictionary translates as "basting sauce" or "gravy". This could mean something coated over the emulsion or something added to the emulsion.

PE

Ray Rogers
02-02-2011, 11:02 AM
I have positivly tracked down one of those "unknowns".
I do not think erythrosine was the other.
It seems to me it is possible you might actually be looking at a different formula than what you think
as I don't recall any such wording.... but I will have another quick look.

e-mail me if you want to compare notes or describe that "indication".

OK,
I had a quick look and I see where you are getting that erythrosine bit...
It still seems you might be mixing two different formulas.

Ray

Ray Rogers
02-02-2011, 11:38 AM
Is it possible that they work there as sensitizers? AFAIK the dye must adhere to the silver halide to pump energy in it in order to work. Is this possible from overcoat?


You are correct.
Generally speaking, dyes do need to be in close contact with the AgX, however there are some rather interseting ideas or theories on what might be possible under special conditions, although in the "dip" method, there was enough time allowed for the dyes to be fully absorbed/adsorbed... so no fancy theories are needed.

I guess it is possible that some coating methods would not allow for such absorption to occur and so the desired sensitization might not take effect.
at least not immeadiately.

However, OTOH, it is well known that many chemicals can be either
mixed into the emulsion
or
coated as a separate layer and still be of some utility.

Sometimes the chemicals can even be added to the developer or the packaging.

Q.G.
02-02-2011, 11:43 AM
The German wording is unclear. They use a word which my dictionary translates as "basting sauce" or "gravy". This could mean something coated over the emulsion or something added to the emulsion.

What is the original German wording?

Ray Rogers
02-02-2011, 12:14 PM
possibly begiess... ?

But I would probably translate that "dowse", "douse" or even simply "add".

Q.G.
02-02-2011, 12:21 PM
possibly begiess... ?

But I would probably translate that "dowse", "douse" or even simply "add".

It's no more than "pour on" or "pour over".

Ray Rogers
02-02-2011, 12:26 PM
Right.
But if you look at the word "Baste"
there is some similarity... and I can imagine it being translated that way by...
a chef perhaps?

Actually now that I looked back at PEs post I can see where "sauce" might come from:

Begiess Zusatze (umlaut on the a)*


*((I forgot how to make umlauts in MS Word... anyone know?))

Photo Engineer
02-02-2011, 12:57 PM
Ray;

Since one formula states the dye is "unbekannt" or unknown, and another formula for a different paper specifically states Erythrosine and gives the exact amount and dilution, I have only suspicions that they are using Erythrosine in Brovira. It is certain to me that Brovira is sensitized though, by some means.

It is also clear that the formulas give in Glafkides omits two items. They are, the dye that is unbekannt and the overcoat with its materials for matting, gloss and keeping. In some formulas, the stabilizer is actually in the emulsion. In any case, it is omitted. This is all according to my notes on Brovira.

But then, I have seen 2 or 3 versions of these. One is in the BIOS reports and the other is in the FIAT reports. The third comes from derivative sources some posted here including Glafkides. Since the third sources seem mostly sins of omission so to speak, I think that is what they are. The types from the original reports do differ though and this has been reported elsewhere.

PE

Ray Rogers
02-02-2011, 01:31 PM
I have a splitting headach again but I will try to respond.
I think we agree with the first paragraph,
but why it is certain to you that Brovira was sensitized
could perhaps be explained in some detail...
Is it just the obvious and undisputed "unbekannt"s,
a lack of speed in your recreated versions,
or published spectral data from actual period emulsions?

My memory says you are right about Glafkides, but I don't hold that against him.
In fact I think it was he who warned about how messy the reports were.
Besides, he only listed a few of the formulas anyway, and as you know there are a lot of them.

I do not think that all of the Broviras were sensitized- although some were.

One of the dyes I know by both name and structure but another just by its chemical name....

Photo Engineer
02-02-2011, 01:48 PM
My notes read: "Sensibilisierungs-Farbstoff-S to-Gemish 1:1000 X, Losung X) Konsitution hier unbekannt" Or Sensitizing Dye S mixed 1:1000, composition is unknown here.

You are right, some were and some were not. Portrigas also had a dye.

PE

Q.G.
02-02-2011, 01:58 PM
Right.
But if you look at the word "Baste"
there is some similarity... and I can imagine it being translated that way by...
a chef perhaps?

Actually now that I looked back at PEs post I can see where "sauce" might come from:

Begiess Zusatze (umlaut on the a)*

Yes, a chef might translate it as "baste".
But it would be putting his interpretation into the translation, that isn't necessarily in the original.
That doesn't mean it is incorrect. On the contrary: it probably is quite accurate.


*((I forgot how to make umlauts in MS Word... anyone know?))

Alt-0228 =
Alt-0246 =
Alt-0252 =
;)

Ray Rogers
02-02-2011, 02:00 PM
Q.G.:
Does that mean I push "ALT" followed by the #s? , like this...
or perhaps at the same time, like this...
well that did not work...
(maybe because I am using a Japanese keyboard its different?)

more guidence needed!

Ron:
Right. That looks to be page XL, btw.

Q.G.
02-02-2011, 02:16 PM
Press Alt, and hold it until you have entered the 4 digit code (on the numerical keypad).