510 Pyro and Pyrocat HD, is there really a difference?

Hi everyone, I've searched around the internet regarding this question but I couldn't really find anything useful, strangely, so I'm sorry if it has been asked many times before.
I've been curious to try 510 Pyro for a while now, I read countless threads with people either swearing by it as the best developer there is and others saying it's really not that different from any standard developer. I decided to just try and see for myself. I'm especially intrigued by the alleged shadow detail retention while maintaining very fine grain, which should be good for pushing film (right?) That would be ideal now that it's dark outside. I'm not a frequent shooter so I've always ever used HC-110 and Rodinal.

Anyways, getting 510 Pyro would cost me 45€ including shipping, whereas I found that I can get Pyrocat HD for just 25€, which also has a great shelf life. I read that the former is pyrogallol based, whereas the latter is pyrocatechin based, however I don't understand what that means for the final negative. Does 510 Pyro perform better than Pyrocat HD or are they mostly the same in your actual experience? Thank you!

Lorenzo, I've used PMK and Pyrocat HD for decades now. Buy the Pyrocat for 25€ and try it. I have never had the desire to look for something better.... (50cm x 50cm print)

I use both developers. I did a video a couple years ago comparing the two...

Firstly, IMO there is no "best developer." That said, the main difference between 510-Pyro and Pyrocat-HD is the stain color. The former leans more toward green/yellow, while the latter leans toward a brownish color. But, I've used both formulas over the years (as well as several other pyro-based developers) and have found that the stain color obtained is somehow related to the specific film developed. No idea why, but that's what I've observed in my own use.

Another difference is how they'll print, if you print in a wet darkroom. The 510-Pyro negative will tend to hold back the high values (not as much as PMK, in my experience) while the Pyrocat negative will print with a fairly straight line to its curve. For me, Pyrocat negatives seem to provide an increase in contrast with modern VC papers, but it's easily remedied.

Oh, and 510-Pyro will last just about forever. Opinions vary widely on Pyrocat, but I've had it die within one year of mixing. It does keep better if mixed in Glycol, but I've had that, also, within a shorter timeframe than what I typically see reported. And, what has always bothered me about its "death" is that it's a "sudden death" (like Xtol) and you don't know until your negatives don't develop properly! I still use Pyrocat because I think it's a great formula, but I tend to mix it in small quantities every six months and toss what I didn't use.

I use Pyrocat - I found the necessary ingredients more easily, and it’s not as toxic. After two years, the concentrate is like new, it hasn’t changed at all, but my version is glycol-based.
The main difference I can think of is that Pyrocat is a two-part developer, which gives you the freedom to adjust the ratios between Part A and Part B depending on the results you want. In other words, it’s more flexible.

YES, there's a difference and IMO the differences are significant. I never really liked 510 pyro because there's nothing in my view that it does particularly well. Pyrocat HD is in my experience the superior option of the two.

Aside from pyrogallol/pyrocatechin, there’s also the metol/phenidone difference. Pyrocat MC might be more directly comparable to 510 pyro, because both use phenidone and ascorbic acid. I haven’t used 510 pyro so I’ll leave that part of the discussion to others, but pyrocat HD and MC are wonderful developers and do last for quite a while in glycol.

You don’t state how you’ll be printing, but the stain color will primarily affect VC papers. Given the price difference why not try the pyrocat? You won’t be unhappy with it and it will give you a baseline for what to expect from a pyro developer.

Of the various tinkerers Sandy King at least went to the effort of carefully testing Pyrocat-HD and attempting to show / characterize the results (speed, image structure, characteristic curves) as objectively as reasonably possible. It does this, it does not do that. Etc. Most other concoctions around are pretty haphazard. They will develop film, but that’s fairly trivial.