I, for one, have been trying to test both pyrocat hd and 510 pyro. Before I go farther, I should say I'm getting pretty tired of the pissing contest that is going on here. This is a discussion group and if you have some ax to grind, do it somewhere else. There are a few thousand others listening that are trying to wade through all the crap and make decent negs. Be nice.
That said, I have been using PMK for some years, over 15, with HP5+ and I have had my problems, but with testing and help from Gordon, I've worked out the bugs and it works for me. It doesn't come for free and this is why I'm looking for something better if it is there to be had. There are some chemists here. I cannot keep up with them. I did well in college chemistry, but most of this stuff is beyond me. And I don't know what BTZS is either. I know the intials, but I don't go to their church. This doesn't make me a bad photog, IMO. I can make a pretty dam good neg and print. I can do it consistantly. I do know about and use light integration and pray there regularly. I don't think any of this is necessary to being a good photog. I will speak for the masses now, we just want a developer that works for us with as little thought as possible.
In my as yet very brief exposure to pyrocat and 510, I have discovered the following with regard to HP5+ in a Jobo 3xxx drum and a rotary base.
Pyrocat.
Pyrocat is a well documented recipe and seems to have many users.
It is not as energetic as I thought it would be.
It has almost no stain that I can see with my eye or read with my blue filter.
Metol cannot be substituted for phenidone at the given ratio with only speed loss. Metol seems to make the developer exit the drum looking like ink.
Sodium carbonate and potassium carbonate are not interchangeable with invariant results. The pot carb did not give as much density.
FBF = 0.15
510
The developer leaves the drum not clear, but either inky or with lots of color.
My fix turns orange.
This is independent of presoak.
The color in the develper is still apparent if the film is developed in a nitrogen atmosphere. This means to me that the developer is not turning color from oxidizing as is the case of PMK.
Stain is good, but not as high as PMK. (I have never thought my PMK stain to be green. It is more the color of amber and spectal analysis shows it to be relatively flat in the blue-green and uv specta.)
FBF is about 0.27 (fbf for PMK is 0.24)
Images with 510 look okay, although I have not printed them.
As mentioned in another post, I have questioned the age of my chemicals, but I believe they are okay. They seem to be the same colors as others here and they seem to work in other formulas that I'm using with the consistancy they have always had. I am willing to continue to work on these developers to adjust them to my work as they show some promise. I feel I need to settle on one recipe for pyrocat and I need a little more energy from pyrocat, too. I'd like to here from some of the average users like myself. Please contribute some info to the database that is building here, because it is by no means complete. I'd like to know if anyone has had similar experiences to mine.
YMMV