October 2022 – Koraks tinkers

Fairy dust – Dry pigments for color carbon

Alright, I caved. I had been ogling the website of Kremer Pigmente for a few weeks and ultimately I decided to order some pigments from them. I think it actually makes sense, despite the warnings I was given by multiple people on the forums. After all, dry pigments are challenging to work with. Or so they say…

Color me purple – Some color developer formulas including C41 and RA4

Despite the modest resurgence of interest in film photography, supply issues remain a concern. This is nothing new; a few years ago, I already worried about this and figured that I wanted to expand my options when it came to in particular color chemistry for C41 negative development and RA4 printing. I started collecting formulas I found online, purchased the necessary chemistry and mixed quite a bit of (mostly) developers myself. Now seems a good time to share my findings with you. If anything, it might be convenient to have some key formulas in one place.

Roll another one…modifying the Durst RCP20 for RA4 processing

Sometimes I’m just incredibly lucky. Tabletop RA4 roller transport processors are unobtanium these days and if you find one, it is likely to be insanely expensive. I happened across a Durst RCP20 (which in fact is a Thermaphot machine, but Durst sold them under their own brand). These machines have a few drawbacks though, which boil down to them being darn old pieces of equipment. First and foremost, to be able to use mine, I had to convert it to run at the right speed for the current RA4 color paper process. Here’s how I did this.

Fade to grey – The pigment balance problem

Open any book or web page on color printing and it’ll say at some point that all pigments or dyes used in the process should mix to a neutral grey or black – at least in theory. It’s an issue I’ve been ignoring throughout my color carbon adventures so far. Well, not exactly ignoring, but I didn’t spend sufficient attention to it, certainly not in writing. Allow me to make up for this, at least in part. In this blog, I’ll explore the issue of pigment balance and try and work out a way to determine, at least with rather coarse resolution, a usable pigment balance for color carbon tissues.

The curve is dead, long live the curve – the linearization game, part 3

After observing a bit of a problem with a lack of linearization and setting myself up for embarking on the effort of linearization, it’s time to describe this actual linearization process itself. It’s going to be a dish with inkjet digital negatives as the main ingredient, broiled in a broth of GIMP with generous lashes of Excel and a good whiff of intuition, topped off with some guesswork for good measure. It’s going to be a bumpy ride!

Straight ahead– the linearization game, part 2

Previously I wrote about the necessity of linearization: if you print an inkjet digital negative, what densities you can expect from the resulting carbon transfer print are a bit of a gamble. Put differently: the relationship between inkjet negative density and print density is not a linear one. To get color to work reasonably well, I’ll need to linearize my curves reasonably well, too. It’s a bit of a chore, but…well, no but, and not a ‘bit’ either. It’s just a chore. And there’s actually some preparations to be done before I can start with the…err, preparations. (I’m not sure when I’ll get to the actual printing, come to think of it!)

Kinky curves – the linearization game, part 1

It’s starting to become a series of blogs, this color carbon project of mine. Not that I expected it to be easy, of course. Note the title of the first installment. I knew what I was heading into. And here we are, right in the middle of it all. Frankly, this is my least favorite part of a hybrid process: the struggle to get something that displays as e.g. 10% tone value on a computer screen to print as a 10% tone value on paper. In other words: linearization. Let me share my woes with you for a minute, while also briefly touching upon the topic of layer order and assembly of the color image.

Beam me down, Scotty: a new ultra-simple UV light source

It’s been a while since I wrote a somewhat acrid blog about the 300W UV floodlight unit I bought from AliExpress. The tone was acrid, because 300W in reality turns out to be about 75W. The conclusion was somewhat counter-intuitive, as I also mentioned that I found the unit so abysmal, I planned to buy some more of them. The reason is simple: while the unit doesn’t live up to its specifications, it still gives a lot of bang for your buck, and most importantly, it’s super easy to implement. Well, you be the judge of that!