Does anybody make Diazo Prints?

Photo Chemist · Jan 14, 2019

I am preparing a lab for my students where we will make diazo prints. The reference I have is a 1989 Journal of Chemical Education article. The diazo compounds it references (4-diazo-N,N,-diethylaniliine tetrafluoroborate) is discontinued by one of the big chemical suppliers. There are other diazo compounds that can be used, but it seems they are equally scarce.
If you make diazo prints - what is your source of the diazo compound(s)?
Thank you!

removed account4 · Jan 14, 2019

hi there photo chemist !
i've never made diazo prints but ...
blick art supply sells diazo emulsion and sensitizer
https://www.dickblick.com/products/speedball-diazo-photo-screen-printing-emulsions/
maybe it is similar to what you are looking for ?
have fun with your lab !
john

glbeas · Jan 14, 2019

I used to use diazo coating for lithographic plates for the newspaper press, seems to be the same stuff as the sensitizer in the silkscreen emulsion, which I also used quite a bit when I was making silkscreens. The stuff seems to be pretty much all or nothing image wise, so I am curious about the process you would use to make a diazo print.

tezzasmall · Jan 15, 2019

Hi Dominique,

I've just reread some links about diazo printing, having done so before when a question was asked. It appears to be a screen printing process. To make things easier it would best to buy one of the inexpensive kits available, rather than individual chemicals and having just looked, the same kit that John mentions above, is readily available in the US and UK. Just search for 'diazo printing'.

Here is a link to a blog that gives the outline of the process:

https://www.handprinted.co.uk/ramblings/how-to-use-diazo-photo-emulsion

Terry S

Photo Chemist · Jan 16, 2019

jnantz said:
hi there photo chemist !
i've never made diazo prints but ...
blick art supply sells diazo emulsion and sensitizer
https://www.dickblick.com/products/speedball-diazo-photo-screen-printing-emulsions/
maybe it is similar to what you are looking for ?
have fun with your lab !
john

It might. At the very least, it has the diazo (light sensitive) compound that i'm looking for. If anything, we could use the emulsion from the kit this semester while we try to located the diazo compounds.

Thank you!

glbeas · Jan 16, 2019

https://www.dickblick.com/items/43304-1002/
This would be a bit cheaper just buying the diazo

removed account4 · Jan 16, 2019

thanks gary i didnt' see that
good luck Photo Chemist !
john

Photo Chemist · Jan 16, 2019

tezzasmall said:
Hi Dominique,

I've just reread some links about diazo printing, having done so before when a question was asked. It appears to be a screen printing process. To make things easier it would best to buy one of the inexpensive kits available, rather than individual chemicals and having just looked, the same kit that John mentions above, is readily available in the US and UK. Just search for 'diazo printing'.

Here is a link to a blog that gives the outline of the process:

https://www.handprinted.co.uk/ramblings/how-to-use-diazo-photo-emulsion

Terry S

I was sure I had replied...but I guess I started and didn't finish!

Thanks, Terry! I looked at the link and it reminded me that I have a friend with a screenprinting business. I didn't realize that she used a diazo compound (emulsion) for her work. She texted me a link to her goods. I think it might work. It depends on how thick the emulsion is. (Apparently, as my husband and I (both chemists) discussed the meaning of emulsion, we decided that our definition is not quite the same as those of artists for "emulsion). In any case, she said it was locally available - by itself or as a kit.

Photo Chemist · Jan 16, 2019

glbeas said:
https://www.dickblick.com/items/43304-1002/
This would be a bit cheaper just buying the diazo

Yes! That might be perfect! Crazy that it's readily available at an art store, but you can't get it from Aldrich! Thank you for the link.

nmp · Jan 16, 2019

Photo Chemist said:
Yes! That might be perfect! Crazy that it's readily available at an art store, but you can't get it from Aldrich! Thank you for the link.

Not sure if the molecules used for screen printing emulsion making would function as a replacement in white-printing process. They might as well. The two processes operate under different chemical mechanisms.

However, Sigma-Aldrich does have an analogous molecule (expensive!) to the one you originally mention:

https://www.sigmaaldrich.com/catalog/product/aldrich/283088?lang=en&region=US

glbeas · Jan 16, 2019

What is the process of making a diazo print? Is it anything like a gum bichromate print? If thats the case the silkscreen emulsion might work with pigment mixed in.

nmp · Jan 16, 2019

glbeas said:
What is the process of making a diazo print? Is it anything like a gum bichromate print? If thats the case the silkscreen emulsion might work with pigment mixed in.

I am assuming the OP alluded to this process (see Section 4.3) that is distinct from the cross-linking mechanism of the emulsion making or the gum dichromate:

http://cool.conservation-us.org/jaic/articles/jaic39-03-005_4.html

Photo Chemist · Jan 17, 2019

nmp said:
Not sure if the molecules used for screen printing emulsion making would function as a replacement in white-printing process. They might as well. The two processes operate under different chemical mechanisms.

However, Sigma-Aldrich does have an analogous molecule (expensive!) to the one you originally mention:

https://www.sigmaaldrich.com/catalog/product/aldrich/283088?lang=en&region=US

Yes, this is actually the one we're ordering. There was a recent journal article that that I saw this afternoon that used this molecule and reported that it worked well. Thank you for taking the time to look. I really appreciate it.

Photo Chemist · Jan 17, 2019

glbeas said:
What is the process of making a diazo print? Is it anything like a gum bichromate print? If thats the case the silkscreen emulsion might work with pigment mixed in.

It's sort of analogous, but different. They both use UV light, but the chemicals doing the "work" have a different way of working. The procedure that I am having my class use (on Tuesday!) will use water color pigment to form the image. When you use a solution gum arabic with water color pigment and add potassium dichromate under UV light (or in our instance a light box), the gum arabic polymerizes and makes a film. In the exposed areas, the water color is then trapped in the polymer.

With the diazo print, the diazo compound "couples" (reacts) with another molecule. This new molecule forms a color that is visible to us once it's held over ammonia. Both use a negative contact print and both use UV light. The mechanism/chemicals are just different.

darkroommike · Jan 17, 2019

I have used diazo film to make dupe prints from title slides in 35mm size and large prints, too. The stuff I used had a transparent base and was available in several colors, positive to positive or negative to negative. There used to also be a 4x6 Microform and 35mm microfilm diazo duplicating film and a large sheet blueprint material. The downside is that all of these products worked best when developed with concentrated ammonium hydroxide. Strong nasty stuff and unfortunately much harder to get than it used to be since it is one of the ways to make meth.

Photo Chemist · Jan 17, 2019

darkroommike said:
I have used diazo film to make dupe prints from title slides in 35mm size and large prints, too. The stuff I used had a transparent base and was available in several colors, positive to positive or negative to negative. There used to also be a 4x6 Microform and 35mm microfilm diazo duplicating film and a large sheet blueprint material. The downside is that all of these products worked best when developed with concentrated ammonium hydroxide. Strong nasty stuff and unfortunately much harder to get than it used to be since it is one of the ways to make meth.

Yes, depending on the molecule that you react it with/couples with, it can have different colors. And yes, you develop it over ammonia (I fixed my post above - I had it written that the gum dichromate is developed over ammonia.) Was household ammonia too weak of a solution to develop it? In any case, I think we'll be ok since it will be part of a chemistry course.

nmp · Jan 17, 2019

Photo Chemist said:
Yes, depending on the molecule that you react it with/couples with, it can have different colors. And yes, you develop it over ammonia (I fixed my post above - I had it written that the gum dichromate is developed over ammonia.) Was household ammonia too weak of a solution to develop it? In any case, I think we'll be ok since it will be part of a chemistry course.

I am wondering what your formulation is going to be. If I understand correctly, the reason for ammonia treatment was that the coating contained an acid in addition to diazo and the coupler in order to retard the coupling reaction from taking place in the paper in situ. After exposure, the ammonia neutralized the acid, allowing coupling to take place in the unexposed areas. This was necessary for commercial applications where they wanted to have all the chemistry pre-applied on the paper and all the customer had to do was inhale some ammonia...

I suppose the ammonia treatment can be eliminated if a coating is made of straight diazo, exposed and then treated with the coupler as a sort of a developer to get it to form the azo dye.

Sounds like a very interesting class....please do share how it goes.

Photo Chemist · Jan 17, 2019

nmp said:
I am wondering what your formulation is going to be. If I understand correctly, the reason for ammonia treatment was that the coating contained an acid in addition to diazo and the coupler in order to retard the coupling reaction from taking place in the paper in situ. After exposure, the ammonia neutralized the acid, allowing coupling to take place in the unexposed areas. This was necessary for commercial applications where they wanted to have all the chemistry pre-applied on the paper and all the customer had to do was inhale some ammonia...

I suppose the ammonia treatment can be eliminated if a coating is made of straight diazo, exposed and then treated with the coupler as a sort of a developer to get it to form the azo dye.

Sounds like a very interesting class....please do share how it goes.

Yes, there is an acid. The uv light/sunlight decomposes the diazo compound. The acid that is present prevents the decomposed diazo compound from bonding/combining with the coupler. When the exposed paper is held over ammonia, it neutralizes the acid and allows the coupling reaction to occur resulting in a color (specific color depends on the coupler).

The class is a mixed bag of non-science majors who don't interact much (yet). We are doing an entire semester of alternative/historical process printing and studying the chemistry behind it. I think it will be an even more fun class as we start making more prints. And I hope the students enjoy it as well. After spring break, we will mix in some traditional dark room work. That will be interesting, as it will be totally new to me.

nmp · Jan 18, 2019

Photo Chemist said:
Yes, there is an acid. The uv light/sunlight decomposes the diazo compound. The acid that is present prevents the decomposed diazo compound from bonding/combining with the coupler. When the exposed paper is held over ammonia, it neutralizes the acid and allows the coupling reaction to occur resulting in a color (specific color depends on the coupler).

The class is a mixed bag of non-science majors who don't interact much (yet). We are doing an entire semester of alternative/historical process printing and studying the chemistry behind it. I think it will be an even more fun class as we start making more prints. And I hope the students enjoy it as well. After spring break, we will mix in some traditional dark room work. That will be interesting, as it will be totally new to me.

Sounds like a wonderful class. I am sure your students will enjoy it. Wish I could have taken it for an audit or something. But I am too far from TN.

darkroommike · Jan 18, 2019

Photo Chemist said:
Yes, depending on the molecule that you react it with/couples with, it can have different colors. And yes, you develop it over ammonia (I fixed my post above - I had it written that the gum dichromate is developed over ammonia.) Was household ammonia too weak of a solution to develop it? In any case, I think we'll be ok since it will be part of a chemistry course.

You need pretty strong ammonia but it doesn't have to be that pure. Ace Hardware has some 10% "Janitorial Strength" stuff that will clear your sinuses from three rooms down.

Photo Chemist · Jan 19, 2019

darkroommike said:
You need pretty strong ammonia but it doesn't have to be that pure. Ace Hardware has some 10% "Janitorial Strength" stuff that will clear your sinuses from three rooms down.

Thanks! I think ammonia will be easy to find. It's good t know that it doesn't have to be gaseous!

darkroommike · Jan 19, 2019

Photo Chemist said:
Thanks! I think ammonia will be easy to find. It's good t know that it doesn't have to be gaseous!

We used to use the 30% stuff (what about 26 Baume?) and it out gasses a lot. But the 10% will probably work, you may need to renew your gass jar more frequently. You and I do not want to mess with anhydrous.

Fred Brookes · Oct 16, 2019

Photo Chemist said:
I am preparing a lab for my students where we will make diazo prints. The reference I have is a 1989 Journal of Chemical Education article. The diazo compounds it references (4-diazo-N,N,-diethylaniliine tetrafluoroborate) is discontinued by one of the big chemical suppliers. There are other diazo compounds that can be used, but it seems they are equally scarce.
If you make diazo prints - what is your source of the diazo compound(s)?
Thank you!

Hello Photo Chemist, I am an artist working in Nottingham UK using various print media including dyeline (using an old OCE ammonia processing machine). I want to experiment with a wider range of colours, but have had no joy with existing coated paper suppliers, so am looking for a d-i-y solution. Have your researches been successful? Have you been able to formulate coatings that can be processed in that kind of way? I would be very interested to learn more about what your experiments have achieved.

Photo Chemist · Oct 16, 2019

Fred Brookes said:
Hello Photo Chemist, I am an artist working in Nottingham UK using various print media including dyeline (using an old OCE ammonia processing machine). I want to experiment with a wider range of colours, but have had no joy with existing coated paper suppliers, so am looking for a d-i-y solution. Have your researches been successful? Have you been able to formulate coatings that can be processed in that kind of way? I would be very interested to learn more about what your experiments have achieved.

Hello!
unfortunately, the diazo print wasn't successful. I could make the diazo compound myself, but for the class it really doesn't interest me at this point. I will be replacing the diazo print experiment with a Platinum or Palladium print. I'm sorry I couldn't be more help.
Dominique

Fred Brookes · Oct 16, 2019

Photo Chemist said:
Hello!
unfortunately, the diazo print wasn't successful. I could make the diazo compound myself, but for the class it really doesn't interest me at this point. I will be replacing the diazo print experiment with a Platinum or Palladium print. I'm sorry I couldn't be more help.
Dominique

Thank you very much for responding so promptly. I am sorry that it didn't work. I am pursuing other lines and still hope to be able to d-i-y diazo paper coating. If I get anywhere, would you like me to let you know?

Does anybody make Diazo Prints?

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