Panchromatic Emulsion

[Ray Rogers]

OK Ray,
Now we both know what Ron knows about these dyes.
Bill

Sorry Bill,
I don't think so!

But, just so people do not get the wrong idea,
please let me point out that I never asked you to find out what Ron knows about these dyes...

(Afterall, when I want Ron not to share his knowledge with me, all I have to do is ask him a question! !)

Ray

[Photo Engineer]

Ray;

Of all of the dyes made only a few passed muster and made it into products. Kodak produced over 2000 new emulsions each year but only about 20 made it into a new product. The same is true of dyes. That is about 1% so I did not deal with many dyes. Paul is the one that dealt with all of them AFAIK except for the chemists who made them!

As for Bill's comment, I think he has covered it well. You both know as much as I do, but Paul knows much much more. You met Paul at the ICIS meeting, and in fact he introduced you to me! Ask him if you need more information.

PE

[Ray Rogers]

Ray, are you happy?

PE

I am happy when my speed and contrast are high, and my fog is low.

The same goes for my emulsions!

[Ray Rogers]

Ray;

Of all of the dyes made only a few passed muster and made it into products. Kodak produced over 2000 new emulsions each year but only about 20 made it into a new product. The same is true of dyes. That is about 1% so I did not deal with many dyes. Paul is the one that dealt with all of them AFAIK except for the chemists who made them!

As for Bill's comment, I think he has covered it well. You both know as much as I do, but Paul knows much much more. You met Paul at the ICIS meeting, and in fact he introduced you to me! Ask him if you need more information.

PE

Very good response Ron.

It is true that very few actually made into common use.
I don't doubt for one second that the best could have been very well kept secrets. We do appreciate your guiding us around the pitfalls,
especially in such cases as this, where code names are in still in frequent use and we really are forced to... yea, work in the dark.

Several days ago I noticed that the product number you quoted did not appear on their website, so I knew something was wrong... since Bill had said he had bought that dye I thought it wise to confirm before he opened it, that they had not sent him the wrong dye... just today you mentioned that the name and curve you obtained from them were labeled differently and in addition to all this... I have detected changes in their homepage over the last 18 hours as well.

So, would you like to hear the News from Lake Wobegon... ?

Ray

[Kirk Keyes]

I have detected changes in their homepage over the last 18 hours as well.

Mr. Peabody - "Sherman, this sounds like something for the Internet Wayback Machine."

Sherman - "Mr. Peabody, what's the Internet Wayback Machine?"

Mr. Peabody - "Well, my boy, it's something that I invented in my spare time. I was tired of printing out entire websites so I could keep track of their changes over the years. So I let the Internet Wayback Machine do it for me."

Sherman - "You mean like taking a snapshot of a website, and then storing it online so we can see what a web site was like?"

Mr. Peabody - "Yes, Sherman. Afterall, there's better things to do than stand around on the Internet taking snapshots..."

http://web.archive.org/web/*/http://hwsands.com

[Kirk Keyes]

Sorry, I couldn't think of any better puns...

[Kirk Keyes]

Hi Kirk,
I wonder,do you have any sugestions as to other dyes, with published structures , that could be used as green and red sensitizers.

Well, I have no first hand experience, but I have a nice book from the 1940s on infrared photography. It has a really nice section on the history of sensitizing dyes.

It says that Erythrosine was discovered in 1884 by Eder. And that there was a renaissance in dye sensitization in 1904, and that Ethyl Red was one of the first dyes identified at that time. Cole Parmer lists Ethyl Red at about $55/25 grams.

It then says that shortly after ethyl red, came Orthochrome T, Pinaverdol, and Pinachrome - all isocyanine analogues, as was ethyl red.

Then Pinacyanol was discovered, and it was the most important sensitizer for red, and it was used in all panchromatic emulsions up into the 1930s. It was a family of compounds, with one variety marketed as Sensitol Red by Ilford for this purpose in the 1920s. Sigma-Aldrich lists Pinacyanol iodide at $90/gram.

The book says Pinacyanol gave good sensitivity in the red and on down into the green, but that it was also used with Orthochrome T, Pinaverdol, or Pinachrome for increased green sensitivity. Pinaverdol was known as Sensitol Green, to go with Pinacyanol's Sensitol Red name.

Also mentioned, Pinaflavol as a green sensitizer form after the First Great War.

And Kryptocyanine and Neocyanine are discussed as popular infrared dyes from the 1930s.

[Ray Rogers]

Sorry, I couldn't think of any better puns...

This should be useful.
How often is it updated?
I have no idea how it to explain it if we can't confirm my observations...

I am not even going to try...

except that I did save the version in question...

Thanks Kirk,

Ray

[Photo Engineer]

Just FYI, Kodak used to list about 20 spectral sensitizing dyes in their chemicals catalog. They are still available somewhere AFAIK, and I have previously posted that list here on APUG. I suggest you look it up and use it to your best advantage. Also, Mees and James has a page or more of data on sensitizing dyes using the same data format that I have used here on APUG. After all, a spectrosensitometer is a spectrosensitometer.

However, doing R&D on sensitizing dyes is a very expensive and time consuming undertaking. Do as much as you wish, but the ones that I suggested here to Bill work very well for Br/I emulsions. In addition, Erythrosine works well if you use the methods I spell out. Data for that is in Mees and James as well.

PE

[Photo Engineer]

Just FYI, I have found the name to the benzothiazole dye noted above. It is: 5-chloro-2-[5-choro-3-(4-sulfobutyl)-2(3H)-benzothiazolidene)-2-metyl-1 propenyl]-3-(4-sulfobutyl)-benzothizolium hydrixide, inner salt, sodium salt CAS # 30457-67-1

Have fun with that one!

PE