Diazo-Sensitized Carbon Transfer

[holmburgers]

Polyvinyl-alcohol is another colloid that can be used for making relief images I guess.

Here are 2 formulas, one for ammonium dichromate and the other for p-Diazo-diphenyl-amine-formaldehyde.

Dead Link Removed

Just came across this and wanted to also see if anything's going on with diazo sensitizing lately...?

 

[mdm]

Not here. Too busy printing. Thanks for the link.

 

[gmikol]

Probably worth a try...but I don't know enough about the stuff. Is this the same thing a lot of alt-printers use to size their paper? Do they not harden it?

Looks like they're recommending a combination of polyvinyl alcohol (PVA) and polyvinyl acetate (PVAc).

--Greg

 

[holmburgers]

Yeah, I have no plans to try it myself... though it's interesting I guess to see a comparison of quanitities for ammonium bichromate & that diazo hardener. Like Charles said, they're quite close.

 

[holmburgers]

Hey fellas,

So what's the final word on where to get the proper diazo sensitizer in the US? And what's the cost?

I intend to make diazo carbon one of my goals while in Rochester, and I'm just thinking about getting a source. It's possible that we could get the formulary to stock it, and the price might be better. Who knows though...

 

[Photo Engineer]

I get a complete color kit from Michaels Art store for under $20.

PE

 

[holmburgers]

Are you talking about a screen-printing kit Ron? I think that the Speedball Diazo sensitizer didn't work for Greg.

Do you think Bud at the Formulary could get a hold of 4,4'-DIAZIDOSTILBENE-2,2'-DISULFONIC ACID DISODIUM SALT, CAS: 2718-90-3?

 

[gmikol]

Wow...It's really been that long since I started this thread.

It's been almost exactly a year since I got the diazidostilbene sodium sulfonate samples, but aside from the initial tests, haven't done much else with it. Need to get back to it.

To get back to holmburgers' question: I only found 2 suppliers in the US, which you identified in (there was a url link here which no longer exists)

Secant's pricing was better at the time, and I guess might still be. I've emailed you the pricing they sent me. I don't know how much demand there might be for a substance like this, especially with refrigeration being a storage requirement for long shelf life. Not sure the Formulary would be willing to stock it.

Might be better off to try and organize a group buy across APUG/DPUG, the alt-photo list, LFF and the B&S forum. Might even get some advantageous pricing that way.

--Greg

 

[Photo Engineer]

Are you talking about a screen-printing kit Ron? I think that the Speedball Diazo sensitizer didn't work for Greg.

Do you think Bud at the Formulary could get a hold of 4,4'-DIAZIDOSTILBENE-2,2'-DISULFONIC ACID DISODIUM SALT, CAS: 2718-90-3?

This is indeed a Speedball kit which I have not opened.

As for Bud ordering chemicals, contact him. IDK.

PE

 

[holmburgers]

Hey Greg, gosh, what a bad memory I have. However, I can't seem to find that email (but I do vaguely remember it). Any chance you still have it?

At any rate I just emailed Secant. TCI comes out to $3.28/gram, sans shipping.

A group buy would be a great idea, and I'd be willing to do some leg work to make that work. Let's see what pricing information we get back and I'll inquire about a larger quantity for a group buy. I will say, the price of this sensitizer compared to dichromate is kind of a bummer...

If 1"² of carbon tissue requires 0.5mL (roughly), then 100 8x10" tissues would require 4L of glop, sensitized at 5% that comes to 200 grams at a cost of $656 (at $3.28/gram). The same sensitizing with potassium dichromate ($15.95/lb) would cost only $7.

Tough sell...

p.s. I'll send Bud a note.

 

[gmikol]

2 quick points...

1) Secant's pricing was way cheaper than TCI's @ 100 grams, and it gets even better if you order a kilo at a time. TCI's prices have gone up about 25% in the last year, it seems. Probably reasonable to expect that Secant's have as well.

2) I believe CMB has pointed out (or it's in the data sheet he posted) that this chemical has a solubility limit at about 3% in water. And a lot of the water in glop is tied up in the gelatin. I think the guidelines he posted (there was a url link here which no longer exists) show 1.5g of sensitizer per 250mL of glop. So for your hypothetical 4L of glop, it's only 24g, not 200.

Dichromate will always be cheaper, but this makes the cost non-prohibitive.

--Greg

 

[holmburgers]

Greg, thanks for making these points. I guess what I was (selectively) recalling was a comment from Mssr. Berger about using H#3 at a similar concentration to the dichromates. But if we can get usable material from concentrations around 0.6% then indeed, that's a great thing. Cuts our 100x price increase back down to about 10x.

Also good to know that Secant's pricing will be cheaper. Hopefully they'll get back to me at some point soon.

Now, Bud from PF got back to me asking a couple questions about theoretically obtaining this chemical, and I could use some help answering them.

1 - What quantity would satisfy this initial experimental phase, for the few people who are interested?
2 - What quantity would be alot and what quantity would be barely enough?

 

[Photo Engineer]

If you do buy in quantity, you must remember that the azo material is not stable and a large amount can go bad on you over time. So, if you need only 10 grams for a year, buying 1 kg for 10 people will give each 100 g of which 90 g might go bad.

PE

 

[CMB]

I was (selectively) recalling was a comment from Mssr. Berger about using H#3 at a similar concentration to the dichromates.

To clarify:


To tray sensitize pre-made carbon tissue in Hardener #3, try a concentration (typically 3%) and soak time similar to dichromate.


To incorporate hardener #3 into a gelatin emulsion, 1.5 g/250 ml is a good place to start.


Charles

 

[holmburgers]

Good point to note PE.

Charles, thanks for clarifying this. Since an incorporated sensitizer is one of the most appealing aspects of diazo, it's nice to know that the required quantify is significantly lower, at about 0.6%. This puts things back into the cost-effective zone.

I heard back from Secant, but nothing on a price yet. The nice gentleman who responded told me that this product was used in the manufactur of cathode-ray-tubes, I assume he meant the aperture masks, but he said that since this industry is more or less dead now, it's not manufactured on a large scale. They only have about 60 kg.

I hope my comment, "well we'd probably be looking for 1kg or less..." didn't scare him off...

 

[Photo Engineer]

If they have 60 kg, it must keep better than I thought.

PE

 

[keesbran]

To incorporate hardener #3 into a gelatin emulsion, 1.5 g/250 ml is a good place to start.
Charles

This worked very well for me
I used a 10% gelatin solution, it makes a gelatin/diazidostilbene ratio of 0.06 (6 grams per 100gr gelatin, or 1 gram per 16,7 gr gelatin used).
I'm currently experimenting with a lower ratio of 0.04.

kees

 

[holmburgers]

Ok, received word back from the aforementioned supplier.

I'm told they can supply it at $180/kg. That comes out to 18¢/gram!!

Now, I'm not ruling out the likely possibility that this is a typo and that he meant $1800/kg. Regardless, that's still an excellent price at $1.80/gram. I will clarify this and report back.

So, how to proceed? If by some miracle it really is $180/kg, I think that organizing a significant group buy could be easily done. Even at $1800/kg I think we can get some people in on this.

What venues should we explore for organizing a group buy? APUG, the Yahoo! Carbon Transfer group, Bostick & Sullivan, ____(??)...

 

[keesbran]

Ok, received word back from the aforementioned supplier.

I'm told they can supply it at $180/kg. That comes out to 18¢/gram!!

Is this price quote from Secant? It would be amazing if true. I would go for the kilo!

Kees

 

[holmburgers]

Yes it is. I know, it definitely seems too good to be true, but *fingers crossed*...

 

[holmburgers]

Ok, stop the presses. The price is indeed $180/kg.

I am still communicating to get the specifics (like shipping, etc.), but this seems like a really great opportunity to get this stuff at an unprecedented price. I think that at this price it should be possible to find enough interest for several kg's. I mean, I too would would consider buying one for myself, and I suspect more might feel the same way. It should be noted that there is only a quantity of 60 kg or so total, and that this represents a previous manufacturing run. The industry demand is different now and subsequent production would be on a smaller scale and thus, more expensive. This is what I was told.

So, we need to do some organizing here methinks. Greg, Kees, anybody else, are you guys in? Why don't we convene through email and start a chain to figure out some of the specifics. Logistically, this shouldn't be too difficult, but a concerted effort is probably necessary. I would greatly appreciate any help, and could definitely use it! There are a number of things to consider, like enticing others, handling the money, handling the product and shipping. Sandy King has done group buys in the past and he might be someone to consult on this; not to mention he might be interested in this diazo compound. Alternatively, the Photo Formulary might be interested (and better suited) to brokering this deal, so to speak.

Let's make it happen!

 

[gmikol]

(EDIT: Looks like holmburgers beat me to the follow-up...Chris...you've got my email...)

Secant quoted me $300/kilo last year. If their demand has fallen off and / or they're looking to clear stock, it's not surprising they've lowered the price.

You should also see if they'll give quantity pricing on smaller packaging units (like 100 gm, which they quoted me @$75 last year) if we got an order of >10 units (1 kilo) together, so that no one has to worry about re-packaging from the larger container. Even if the cost / gram is more, it's a lot less work.

As for the group buy, don't forget DPUG (is there anyone here not reading both, though?), and the alt-photo-process list. In theory, this should work with gum as well, though it sounds like Kees didn't have any luck with his initial testing... Maybe the large-format forum (http://www.largeformatphotography.info/forum/), but then again there might be a lot of overlap between there and here.

Group buy would probably only work for USA, though. I'd guess there are too many headaches trying to ship chemicals cross-border.

--Greg

 

[gmikol]

Just wanted to follow up and add a point to get people thinking about what quantity they might want.

Charles Berger's guidelines for about 1.5g of sensitizer per 250ml of finished glop means 6g per liter of glop.

Based on some experiments I made last year, it doesn't seem like you'd want to pour thicker than 0.5ml per in^2 (and possibly thinner), so 50ml of glop for a 9x11" tissue. So that 6 grams of sensitizer would yield at minimum 20 9x11" tissues. 100 grams (~320 9x11" tissues) could be a pretty significant supply for many people.

Why not thicker than 0.5ml per in^2 (with about 11% gelatin)? Thicker than that, and the nitrogen that's given off by the azide breaking down can't escape all that well, and you end up with all sorts of little pinhole bubbles in the dark areas after mating and development (you can't see them in the dry tissue).

--Greg

 

[gmikol]

One more thing...

Anyone considering using this sensitizer should keep in mind that the prints need to be cleared with a specific clearing bath that Charles Berger has posted (there was a url link here which no longer exists).

One of the chemicals, potassium permanganate, is a powerful oxidizer. It is available from the Formulary and B&S, but larger quantities >30 grams are subject to Haz-Mat fees. But 30g will make 5L of stock solution (100L of working solution).

Just FYI...

--Greg

 

[anikin]

It sounds wonderful! When you order, I'd like to get 100g of sensitizer. Add me to the list if there is one.