![]() Secondly, when I started out, I found the Bonavolta web page on C41 and RA4 chemistry very useful. In particular this post where he presents what should be eerily close to an official Kodak C41 formula from the 1980s is of interest. Firstly, there are the seminal posts by PhotoEngineer / Ron Mowrey on the Photrio forum. Usually there are some additional ingredients, like a wetting agent and a sequestering agent (calgon in old formulas or DTPA in more recent ones) to capture rogue iron ions that may spoil the broth.įor actual formulas, I found a couple of relevant sources (the list is not exhaustive).an antioxidant to protect the CD-4 from oxidation this is always hydroxylamine sulfate.a small amount of sulfite apparently to suppress excess dye formation.a little restrainer (usually sodium bromide and a really minimal amount of potassium iodide),.usually some buffering provisions (bicarbonate, bisulfite),.When it comes to developers, there are small (but probably significant) differences, while at the same time they all rely on the same backbone: Especially the bleach has gone through several generations of R&D, mostly improving speed, capacity and robustness. It comes as no surprise then that there are several variants of the color developer formulae – and the same is true for bleaches and fixes, no doubt. It’s just their name for basically the same process. The current (and probably final) color negative process is C41 and it has been the standard color negative process for, ah, 30 years or so? There are, and have been, variants with different names form different manufacturers – for instance, Fuji sells CN-16 chemistry which is functionally the same as C41. And I happen to not really like that approach. Since then, I lost interest in color positives – they’re gorgeous, but I’m more of a printer than a photographer, and the only way to print E6 (at least with decent quality and without dedicating your entire life to it) is by scanning and inkjetting it. Sorry, no E6 – I used to shoot a lot of slide film, but this is all >15 years ago and I had all of it developed commercially. I’ll cover C41, ECN-2 and RA4 developers in this post. With the developers, there are less (or no) ways to get around the real thing. For bleaches and fixes, there are usually workarounds or black & white chemistry that can be repurposed. I’ll focus mostly on the developers because those are the most critical processing step and generally the most challenging chemistry to get hold of. So I thought it might be useful for anyone interested to have a few useful formulas collected in one place. Long story short, over the years, I collected some formulas from various (online) sources, mixed quite a bit of chemistry and collected all this information in neat little Excel sheets. Getting the necessary components like the CD-3 and CD-4 color developing agents used to be somewhat challenging, especially in Europe, but it seems that lately, this situation has actually improved somewhat. I think you could get 240 liter developer quantities, evidently not really intended for the average home user…so mixing one’s own chemistry was a sheer necessity. Back when I did those experiments, there was no commercial offering of processing chemistry for consumers in convenient quantities. There was also a brief time I experimented with ECN-2 film, particularly Kodak Vision3 (also sold as CineStill without the remjet backing). The results were just fine – I never did any very systematic comparisons with big-brand chemistry, but negatives and prints were by all means presentable and usable. I did this quite a bit for C41, and a bit less so for RA4. But how long will it remain available for consumers like me? And are there any other options that perhaps have the same or even better keeping qualities? Questions like these led me to mix my own color developers using dry components. It’s pretty much bulletproof, cost-effective and you basically can’t go wrong with it. ![]() I admit that lately, I have mostly used Fuji minilab chemistry for my C41 processing. If anything, it might be convenient to have some key formulas in one place. Now seems a good time to share my findings with you. I started collecting formulas I found online, purchased the necessary chemistry and mixed quite a bit of (mostly) developers myself. 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. Despite the modest resurgence of interest in film photography, supply issues remain a concern. ![]()
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