Have you ever heard of the Ink Process? No? Well, neither had I till a few months ago.
If you have, then, well, you must read a lot of old german photography books. Cause that’s what I was doing when I came across the following recipe in the fifth edition of “Photochemie und Beschreibung der photographischen Chemikalien” from 1905.
- 10g of ferric sulfate
- 20ml of ferric chloride
- 10g of gelatin
- 10g of tartaric acid
- 300g of distilled water
In addition to that there is a developer made from 1L of water, 4g of gallic acid and 0.5-1g of oxalic acid.
This was described as the “Colas Tintenprozess” or “Colas Ink Process”, a black and white positive process patented in 1880 that at first glance looks incredibly similar to cyanotype, with a sensitizer made up of a source of iron in its +3 oxidation state and a dicarboxylic acid.
The interesting part though is the developer, which instead of consisting of potassium ferricyanide consists of gallic acid (and oxalic acid, but we’ll get to that later).
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Ok, I fucking hate “AI” and the corporate horse it rode in on. Machine learning though? I guess that’s kinda useful?!
I’ve been helping out my friends at KKTO with their project Minute/Year for almost a decade now and a while ago we had run into a peculiar problem. I spent the last few days finally cleaning up the mess it caused and I thought I’d write up what I’ve done cause I’m pretty proud of the result.
In 2023 an audio interface had failed and corrupted a whole bunch of our daily recordings in a subtle yet annoying way. It took us a few days to realize what had happened at which point we power cycled the audio interface and everything went back to normal but it left us with a bunch of corrupted recordings that needed to be fixed.
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A pretty common task for exhibitions I support is to have some kind of tiny unobtrusive media player box that can play a bunch of video or audio files on loop for anything from a small listening station with some headphones to a 4k projector showing a feature video.
Since this has come up again and again for me and I’ve had multiple different versions of a setup like this for which I’ve somehow managed to loose all the source files I’ve decided to write this blog post in the hopes that when I have to do this again I’ll actually remember how I did it this time.
I’m not gonna go into every detail here, like how to set up systemd services, but if you want to take a closer look all the scripts and files are available for download at the end of the article.
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Cyanotypes are cool! But you know what’s even cooler? Making cyanotype negatives on glass plates directly in camera!
As I’ve talked about in a previous article I’ve developed a fairly reliable process to create in-camera cyanotype negatives on agar coated glass plates. They not only look great but also have a much higher resolution since they don’t have the rough structure inherent in paper negatives. On top of that having a negative on a transparent backing opens up the possibility of using it to directly make positive prints from it, which is very exciting.
Let’s talk about my process for making them!
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If you’ve read my previous article you know that there were some loose ends I was meaning to tie up using good old science, specifically the significant loss in sensitivity observed when mixing the classic potassium ferricyanide “developer” with your ammonium ferric citrate or ferric ammonium oxalate.
So let’s do that!
A quick recap
Before we get into it, a quick recap of how the “classic” cyanotype process and formula works!
We usually start out with two compounds, ammonium ferric citrate and potassium ferricyanide which get dissolved in water and brushed or otherwise coated onto some kind of substrate, usually paper.
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