(T)issues – A note on pigment dispersion and chroma

I’ve been working with powdered pigments for a (brief) while now and as a result, I’m starting to come to grips with the pros and cons of this approach. Overall, it’s lots of fun – in fact, this is so far my favorite part of the color carbon project. But there are challenges also to this part. For instance, I recently ran into an issue of tissues that didn’t look quite as nice and shiny as they should. And that actually has implications that go far below the surface!

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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.

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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.

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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.

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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.

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Couleur locale – the search for color in carbon

Technically, carbon transfer printing isn’t ‘carbon’ anymore once it becomes color. Yes, for the black/key layer (if used), a carbon pigment is generally used. But for the other colors, evidently carbon falls short. So something like ‘pigmented gelatin printing’ is more accurate. In any case, as color enters, it brings many questions, issues and concerns. Lots of fun stuff, as well. How about this one: which colors should we go for in the first place? Let’s have a look and see if we can make at least a first step.

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First light – at the end of a particularly long tunnel

Progress! But remember: baby steps. Still, today’s baby step is a bit of a symbolic one, because it’s the first actual carbon transfer color image. With some caveats. Well, not some. Many. But still. Colors!

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Baby steps – enter the torture test

No, I have not yet given up! In fact, I’ve been making some progress on the color carbon transfer front. Last time, I made some cyan, magenta and yellow tissue with my newly acquired paints. Only five 4×5″ sheets per color, which is ample for some initial testing. This testing is underway, results so far are promising, and there’s even some progress on the digital negatives front!

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Sickly colors – the crossover issue

I like to print color RA4. That’s no secret. And I like to tinker. I’m not alone in this, and as a result, working with color film and printing color RA4 pops up regularly in one way or another on the photo forums. One issue that often meshes into technical discussions on ‘analog color’ is that of color crossover. Some people immediately ‘get it’, probably because they have experience looking at and analyzing color crossover. Others struggle with the topic and don’t know exactly what to look for. In this post, I’m going to try and illustrate the issue through some (digital!) mockups.

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Why RGB LEDs suck for a color RA4 enlarger

Not many people are crazy enough to build a light source for a color enlarger. From time to time, someone picks up the challenge and posts about it online. Most of the time, the concept revolves around some form of RGB LEDs, whether that be led strips, Chip-On-Board (COB) LEDs or even addressable LED ‘beads’ such as the popular WS2812. All of these are in my opinion doomed to fail miserably to produce quality RA4 prints. Let me explain why.

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