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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The Big Ugly, part 4: (im)perfect present

Here we are, and this is Now. So far, I have written about the two generations of problematic and/or quasi-successful color enlarger light sources I’ve made and the lessons I’ve learned along the way. But all that is in the past. This blog is about the current, 3rd generation of the LED color light source for my (t)rusty Durst 138. It incorporates most of the lessons I learned along the way – and brought me some new ones, no doubt.

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The Big Ugly, part 3: proper SMD LEDs, but no cigar (?)

In the previous part of this series, I told about the lessons I learned by trying to use a single RGB COB LED as a light source for both RA4 and B&W enlarging. I took those lessons and gave it another go, this time using a fundamentally different approach. As the title suggests, no cigar yet – although this isn’t really accurate. The second generation device I built was actually used for a year or two before I was sufficiently annoyed by its shortcomings to replace it. So the second generation actually did work – albeit with some caveats.

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The Big Ugly, part 2: the RGB COB LED approach to color enlarging

Previously, I explained why I thought I needed a color light source and in general terms what it should be capable of. I also highlighted that it’s not so much a project with a clearly defined end (or at least, that hasn’t materialized yet), but more of a journey that continues into the present, and probably future as well. In this part, I’ll go through the phases this project has gone through. That is to say, there are really three distinct generations of the device I’ve built, and each has taught me different lessons. Before going into some details of the current (and 3rd) rendition, I’ll try to go through each generation and explain what it was/is and what its main caveats were (especially generations 1 & 2). Let’s start with the first generation I built.

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The Big Ugly, or building a LED color printing light source. Part 1: the beginnings

Previously, I bashed compound/integrated RGB LEDs such as RGB COB LEDs for the application of a color enlarger for RA4 prints. That was basically a lesson learned the hard way when building a LED-based color enlarger light source. In this series, because one post is probably not going to be enough, I’ll highlight some aspects of the system I’ve built. Or I should say: I’ve built so far, because it’s really just a prototype that will likely never be really finished. Hence the title, The Big Ugly. Because there’s one thing it isn’t, and that’s beautiful. But hey, it works! Sort of. Most of the time. Within reasonable limits. If I’m careful.

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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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Some light to the darkroom

What’s the essence of a darkroom? That’s right – light! Seriously though, I think good light makes all the difference in darkroom work. First and foremost, it’s just pleasant to have ample and good-quality light to work with. But it’s also essential for judging print quality and properties such as hue/color balance, toning etc. In this post, I’m showcasing my current darkroom lighting setup and I will also discuss some lessons learned and loose ends/issues.

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PVC development tubes for sheet film

Warning: again a total lack of originality on my part. The upshot is that apparently I don’t suffer too badly from the not invented here syndrome because I proudly stole reproduced this idea from Tim Layton whom in turn was inspired by Phil Davis and his “Beyond The Zone System” approach. The whole idea is essentially just a hollow tube with two end caps in which you put a single sheet of film, fill ‘er up with developer and agitate in whichever way you fancy. This could be a fancy water bath agitator like in the official BTZS approach, or, as in my case, simply turning the tube over and over like a regular daylight tank, or rolling it on a counter top.

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