Cyanotype enlarger

[adelorenzo]

Someone posted a working cyanotype enlarger on reddit recently. Pretty cool, the biggest worry I'd have is the 20+ minute exposure times. You'd need to keep things pretty darn steady.

https://www.reddit.com/r/Darkroom/comments/4a000o/im_building_my_own_enlarger_for_making_cyanotypes/

Here are some example prints:

http://imgur.com/a/ed8cE

 

[jeffreythree]

Looks like it is just a very bright homemade led enlarger since there is no uv output.

 

[mike c]

Those little LEDS must put out a lot of light too expose cyanotype thru an enlarging lens, even at 20 min.

 

[calebarchie]

Reddit is a terrible place but I applaud the effort. It works, but does it work well?

As for digital negatives and 'cheating'... come on now..

 

[Andrew O'Neill]

"As for digital negatives and 'cheating'... come on now.."

Yes, I too thought that was a silly thing to say. Anyways, he stated that he uses an alternative formula called blue sheet. Never heard of it, nor could I find anything about it on the internet, ie a formula.

 

[pdeeh]

he says about this "blue sheet" is this

I looked around for a solution for a while until I found an alternate formula called "blue sheet" (since it colours the paper slightly blue instead of yellow before development) that uses potassium ferrocyanide instead of potassium ferricyanide. It was apparently used quite a lot in commercial architectural blueprints in the early 20th century, but there is very little information about it now and it seems barely anyone uses it. Which is weird, since it blows regular cyanotypes out of the water. It's a lot more sensitive and has a much better tonality. You don't need to completely overexpose the image like with the regular stuff. The only drawback is that it's not a print-out process, so you can't see how your image is coming along, and it takes an extra oxidizing step to get the final image, but it's totally worth it.

It is always very annoying when people give all these half-digested bits of "information" ... hard work therefore of course to verify or falsify their claims

 

[michr]

The gist of the formula they mentioned using potassium ferrocyanide instead of ferricyanide, and that it is a developing out process. I'm a little skeptical of any difference in ferro vs. ferri cyanide, other than the name, but I'm no chemist. I wonder if it's just a matter of coating the paper with the ferricyanide, exposing, and then developing under a bath of ferric ammonium citrate.

Another possibility is that significant UV is getting through the glass from the LEDs, and they're using a lens that happens to be well-corrected for UV. Less likely, for sure, but a possibility that needs to be eliminated, at minimum for safety's sake.

I have to applaud the person for coming up with this idea and seeing it through in spite of many saying it wasn't possible. Perhaps we'll find out why it works in the future, but if we can replicate the process, the inventor has added something to photography through their efforts.

Also, the computer switching power supply to drive the LED and attaching everything to the tripod head was some great thinking. This project is a neat hack all the way down.

 

[michr]

more details, quoting https://www.reddit.com/r/cyanotypes..._subreddit_seems_a_little_empty_and_i/d031tpp

The enlarger uses a 100W super bright LED, a collimator lens from ebay and a regular camera lens as projection lens. It's still a prototype right now, so it's mostly built from plywood and held together with rubber bands, but it works. The film is held in a slide frame and everything is cooled with two 80mm fans.

The prints were made using an Asahi Optical f/1.4 50mm lens at an aperture of f/2.

Here is a photo of the current state: https://40.media.tumblr.com/2ddc0339852ae72b96e47bb669e050ed/tumblr_nz6zo9W2Sd1uuezfdo1_1280.jpg

I'm currently working with my dad who has a nice machine shop and more experience with this kind of stuff to turn this into a real thing with a proper housing and everything.

I'm also using Ammonium ferric citrate and Potassium ferrocyanide instead of Potassium ferricyanide in my emulsion since it results in much better tonality and sensitivity. There is surprisingly little info about this formula out there, except for some references on it being used in industrial blueprint paper. It's about two to three times as sensitive as the traditional formula, and the details in the highlights are much much better. The overall lower contrast probably makes it a little less useful for contact printing, but if you have a high contrast and high density negative it would probably work great for that as well.

Here is a print of the same image made using the traditional formula with twice the exposure time: http://i.imgur.com/YTMEfxY.jpg

Exposure time for the two A4 sized prints in the album was around 20 minutes.​

 

[pdeeh]

'm a little skeptical of any difference in ferro vs. ferri cyanide, other than the name, but I'm no chemist. I wonder if it's just a matter of coating the paper with the ferricyanide, exposing, and then developing under a bath of ferric ammonium citrate.

WHat do you mean "skeptical of any difference" ? They're different compounds.

As for coating, ferricyanide is not the light sensitive part here - that's the Ferric ammonium citrate.

You can certainly coat paper with Ferric ammonium citrate, expose it, and then "develop" with ferricyanide (I've done it myself, and it is a little faster and a little less contrasty), but it is not clear that this is what the author is referring to.

 

[pdeeh]

It would be very helpful if he would simply post the actual formula he is using rather than just keep referring to it in generalities

 

[calebarchie]

It only works with this particular formular regardless, so unless there are other highly sensitised (eg not printing out) alt processes i can't see it working too well.

Why not use an actual enlarging lens (el nikkors pass UV) and UV LEDs too?

 

[michr]

WHat do you mean "skeptical of any difference" ? They're different compounds.

As for coating, ferricyanide is not the light sensitive part here - that's the Ferric ammonium citrate.

You can certainly coat paper with Ferric ammonium citrate, expose it, and then "develop" with ferricyanide (I've done it myself, and it is a little faster and a little less contrasty), but it is not clear that this is what the author is referring to.

You're right, they are different compounds, so I was mistaken. I went back to look at the wiki pages. The ferrocyanide differs by having 3 molecules of water attached. I don't know how this changes the chemical properties or how to get ahold of the stuff.

 

[michr]

It only works with this particular formular regardless, so unless there are other highly sensitised (eg not printing out) alt processes i can't see it working too well.

Why not use an actual enlarging lens (el nikkors pass UV) and UV LEDs too?

I think it's well-covered elsewhere, but UV lenses, unless they are corrected for UV, like some expensive Pacific Optical lenses, will focus UV at a different place than visible light. The damage UV can cause to the eyes is often stated as another reason UV enlargers won't work or are impractical.

The best reason I could see in using the Takumar lens is that it's a stop faster than a 50mm Nikkor-EL.

 

[calebarchie]

Right - forgot we are enlarging here. I'll stick with my digital negatives, I'm a terrible cheater!

 

[michr]

I don't mind digital negatives, but I like the idea of an enlarger. I've done both digital negatives and interpositives and enlargements onto large sheets of xray film. In either case there's a much bigger investment in time and money than enlarging the negative directly as a cyanotype. This new process won't be the game changer that digital negatives were, but I like having an alternative. Cyanotype enlargements open up the possibility of long exposure in-camera cyanotype negatives as well.

After doing some more digging on the chemicals involved, I wonder, how does this "blue sheet" process differ from cyanotype rex?

 

[calebarchie]

I don't mind digital negatives, but I like the idea of an enlarger. I've done both digital negatives and interpositives and enlargements onto large sheets of xray film. In either case there's a much bigger investment in time and money than enlarging the negative directly as a cyanotype. This new process won't be the game changer that digital negatives were, but I like having an alternative. Cyanotype enlargements open up the possibility of long exposure in-camera cyanotype negatives as well.

After doing some more digging on the chemicals involved, I wonder, how does this "blue sheet" process differ from cyanotype rex?

Well considering I just got a drum scanner... But, perhaps if it worked for other alt process to it may be worth doing, I just don't do cyanotypes at all that much.

 

[cheekygeek]

The author also posted about it in the darkroom subreddit, which I now moderate. A few possible refinements to the design are discussed there. He later posted his first images from the contraption.

Regarding Reddit being a "horrible place", I would agree - as long as we also agree that "the internet" is a horrible place. Subreddits on particular subject are more akin to forums on particular subjects, like this one. People with a common interest hanging out and discussing that particular subject. Reddit also probably has a younger-skewed demographic, though one should not paint entirely with broad brushes if one wants a good picture. (I'm 56).

If we want companies, like Ilford, to continue to produce traditional photographic paper (etc.) then they will need the dollars of the younger generations. Fostering appreciation for film and darkroom work in places where they congregate (like Reddit) is one to help that happen.

PS... Discussion of Alternative Processes is welcome in r/Darkroom.

 

[calebarchie]

The author also posted about it in the darkroom subreddit, which I now moderate. A few possible refinements to the design are discussed there. He later posted his first images from the contraption.

Regarding Reddit being a "horrible place", I would agree - as long as we also agree that "the internet" is a horrible place. Subreddits on particular subject are more akin to forums on particular subjects, like this one. People with a common interest hanging out and discussing that particular subject. Reddit also probably has a younger-skewed demographic, though one should not paint entirely with broad brushes if one wants a good picture. (I'm 56).

If we want companies, like Ilford, to continue to produce traditional photographic paper (etc.) then they will need the dollars of the younger generations. Fostering appreciation for film and darkroom work in places where they congregate (like Reddit) is one to help that happen.

PS... Discussion of Alternative Processes is welcome in r/Darkroom.

I am of the younger sort (20 actually) maybe that is why I am not fond of it? Aside from the strange format and the poor vote system, not a fan of silencing the minority opinion and the whole power mob idea.
There is probably a good reason why someone older like yourself is moderating I also agree most of the internet is terrible too.

As for the enlarger, I see there is merit in it for larger stuff even mural stuff, seeing cyanotype as the cheapest and easiest. My printer is 13" wide so I'm limited to 16x12 but I have been content for far. If I ever want to larger I could give this a try but so far, the results do not seem too spectacular but that could just be a matter of user skill and process (although he shows some 4x5 traditional cyanotypes and they seem fine)