• 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

Panchromatic Emulsion


Ron-- since you're discussing sulfur+gold again, I was wondering why there was such a progression in the use of sulfur compounds over the years. Any ideas as to why thiosulfate was not used from the beginning?

Sheppard in his patent (#1623499) mentions that "sodium hyposulfite" can be used, but then immediately says that this compound is in name correct in the scientific sense and not the compound with the same name used by photographers which is sodium thiosulfate...

By hyposulfite, if he means salts in the archaic system where it's sulfite (SO3=) but with one less oxygen (making SO2=), then (As taken from wikipedia): "However salts containing SO2= and the corresponding acid, hyposulfurous acid (H2SO2) are not believed to exist." - then what would he have been referring to?

OK - I guess I can see it in my 1932 CRC Handbook - it has NaHSO2 and calls is sodium hyposulfite. But I think this is what is called sodium dithionite - not to be confused with sodium dithionate, Na2S206.

So why did he miss thiosulfate in the original patent. He sure listed a lot of other compounds, it seems like thiosulfate would have been something to try, and something they had at hand, too.
 
Kirk;

Since the discovery of sulfur sensitization hinged on discovery that a thiourea was causing it, there was a natural progression in use of heat degradable sulfur compounds. That is my only guess here. IDK why. I do know that formulas from the 40s and 50s used Thiocyanates and then moved to Hypo. Early ones used Thioureas.

I do know (I think, in the back of my memory) that the Thiourea sensitizations were hard to control, and that there was something specific about sulfur + gold where hypo was used. That is it, just a hint of memory.

PE
 
Jesus died for somebody's sins, but not mine! (patti smith)

Ach hum!

Ron, Kirk;

You guys must be sleepier than I am.
Somebody missed hypo, but it wasn't Sheppard!

Ray
 
Last edited by a moderator:
Well, Agfa used Thiocyanate salts for quite a while but Kodak was converting to Hypo IIRC. IDK the precise timeline.

PE
 
Ray Rogers said:
Somebody missed hypo, but it wasn't Sheppard!
Click to expand...

Is it in his first patent? If so, please point it out and then I'll agree with you that it was I that missed it.
 
Kirk Keyes said:
Is it in his first patent? If so, please point it out and then I'll agree with you that it was I that missed it.
Click to expand...

It was in the patent you quoted, with his notes about hypo.
 
It's Hidden View

Ray Rogers said:
It was in the patent you quoted, with his notes about hypo.
Click to expand...

To suggest Sheppard missed hypo verges on being sacrilegious!

However, the position attained latter on by hypo certainly is not reflected in the early published reports, and initally there was some confusion, and a different allocation of emphasis was given. As Kodak did the leg work, their understanding changed.

(PM me if you can't find it)
 
Last edited by a moderator:
OK Ray - I see that I had not found an earlier patent. Thanks for pointing that out...

1574994 (1926) DOES mention the use of thiosulfate as a sensitizer, but 1623499 (1627), the one I quited above, DOES NOT mention thiosulfate. And Sheppard goes on to make sure you know that he's not talking about thiosulfate as well.

So why the difference in the two patents then?
 
Kirk Keyes said:
OK So why the difference in the two patents then?
Click to expand...

Ray - you seem to quote yourself in sequential posts. What's up with that. It confuses me to see you having a conversation with yourself...
 
Ray Rogers said:
It was in the patent you quoted, with his notes about hypo.
Click to expand...

I still missed in in the one I quoted I guess. And my buddy Google Patents doesn't find it when I search on thiosulfate either. Granted, google doesn'thave the best OCR.

Can you please give me page and line number...
 
Kirk Keyes said:
I still missed in in the one I quoted I guess.
Can you please give me page and line number...
Click to expand...

Sure Kirk, no problem!

Page 1
Collumm 2
lines 91 & 92

(I knew that by rote!)

Ray
 
It all began when a couple of amino acids fell in love...

Kirk Keyes said:
Ray - you seem to quote yourself in sequential posts. What's up with that. It confuses me to see you having a conversation with yourself...
Click to expand...

You think you it confuses you?

Since I was 9 I have been interested in the biochemistry of schizophrenia...
I figured it would be best if I could experience it first hand (!)
and I have been waiting a long long time for this!

Autually, this here is nothing more than an afterthought.

I once wrote a paper that dared to suggest that thought itself was a hallucination.

Well, we will be more careful in the future.

I promise.

That was X-Ray speaking.

HE has multiple personality disorder, not me.

In the words of Herman Hesse,
"Tell her I'm a schizophrenic!".

(I promise, too!)

Ray and his X-Ray
 
Ray Rogers said:
Sure Kirk, no problem!

Page 1
Collumm 2
lines 91 & 92

(I knew that by rote!)

Ray
Click to expand...

Thanks. I stand corrected.

And I'm giong to have to ask for my money back from those speed reading/comprehension tapes!
 
Kirk Keyes said:
Would you be willing to sell a couple dozen milligrams of your dye?
Click to expand...

Hi Kirk,
I still have not opened the vials of dyes. But when I do, I will weigh out what you want. I have decided that handeling these dyes merits an analytical balance. I have bid on one on Ebay and the auction ends in 3 days.
I calculate 19 cents per mg as my cost for the dye. I will not try to make a profit here. Just let me know how much you want. There are two dyes, one for green and one for red sensitization.
Regards,
Bill
 
Bill - good luck on you balance purchasing. They sure are nice to have if you want to measure small amounts.
 
SDA3057 and SDE8006

:confused:Hi Ron,
When you suggested SDA3057 and SDE8006 as spectral sensitization dyes I went ahead and ordered them at your word. Since I offered small samples at my cost to interested parties on this forum, I have received questions as to what, exactly, the dyes are. I receieved no paper information with these dyes and I wonder if you have any written data on these dyes, or if you know their chemical names.
Thanks,
Bill
 
The company has refused to give me any data on these dyes, merely to tell me that they are green sensitizers. By testing, I found that one is a red sensitizer and had this confirmed by Paul Gilman, the Kodak expert on dyes. Sorry I cannot help you with structures. I have one partial ID on the red sensitizer. It is used in Kodachrome film!

They are generically probably cyanine dyes.

I have used both, but since the one marked green is really a red, I have fogged all emulsions eventually when using it due to my trusting nature. (BTW, it is a green sensitizer on Chloride and Bromide emulsions but not on Bromo Iodides due to J aggregate formation.)

PE
 
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. I know of several candidates from my studies of the Lippman process and pan holography. But some of these dyes are hard to purchase due to company self imposed rules about selling "hazadous" chemicals to individuals.
I would hate to develope a panchtomatic emulsion, then learn that H.W.Sands has decided to discontinue it.
Regards,
Bill
 
After spending all of that money on a gram each of 5 dyes that I tested, to get 2 good ones, I should have some data, but no, I don't. I was told flat out that this is not available. These dyes are not listed on their web site either AFAIK. So......

And, one of them was stamped with the warning (selenium containing dye) and Paul advised me against using it, so here it sits, a HAZMAT item that cost $100+ and unusable. Another was nearly totally insoluable in every solvent I tested! So, for my 6 dyes I got 2 "good" ones, one insoluable, one a HAZMAT item and I forget the status of #5. Oh, thats right, it didn't work! So much for that.

I have also tried a second source and have 4 more samples. I have not tested these as they must be treated with particular care (not caution), to get them to work. One must be titrated with trimethyl amine first and then dissolved in alcohol just to get it to work! I have not gotten around to that pain in the ****.

Ray, are you happy?

PE
 
I should add that I found a source for an IR dye that could be used in experiments, but the company told me that it would only sell the dye in 1 Kg lots, as it has to be made to order, it goes bad rapidly and it would cost me $50,000 for the 1 kg bottle.

Nice deal. Right?

PE
 
If you look long and hard enough at the W.H. Sands web site, you can see that they have SDA3057 listed on a page that's headed with "Benzothiazoles" http://www.hwsands.com/productlists/benzothlist.htm and says it has a max abs. at 548 nm, an absorbtivity of 80,500, and a solubility of 1gm into30ml (MeOH).

For SDF8006 (I could not find SDE8006, so I'm assuming it's a typo), it has a graph of absorbance on this page http://www.hwsands.com/productlists/visible_dyes/visible_dyes.htm and it says max abs 559 nm, a solubility of 1gm into30ml (MeOH), and a black appearance. OK, no chemical family for that one...
 
Did you guys get MSDS sheets for your dyes? Maybe thay have chemical class listed on there?
 
You must log in or register to reply here.
Menu
Log in
Register