There are several Pyro developers out there. PMK is the only one I have used, so what I'm going to tell you applies only to it.
PMK is diluted 1+2+100. It has two separate stock solutions. You use one part Solution A, two parts solution B, and 100 parts water. I add 10ml of A and 20ml of B to 1000ml of water.
I've found that HP5 gives the best shadow detail exposed at EI-250. I'm scanning my film, and have never tried printing film developed in PMK in the darkroom. The yellowish stain affects silver-based paper differently than a scanner, and that is especially true if you print on VC papers. My developing times may need changed if you print in the darkroom.
I develop HP5 for 9 minutes at 75 degrees (24C).
Pyro developers are a lot more toxic than normal developers. Wear Nitrile gloves, not latex (some chemicals can pass through latex). Buy the Liquid PMK kit, not the powder. Mixing powders always gets some into the air, and if you breathe it, it gets into your bloodstream much faster than it would through skin absorbtion.
Use distilled water to make your working strength developer. Water quality can affect how PMK works.
Having said all that, there are really only two things about PMK that have to be done much differently than other developers (you should wear gloves with ANY chemicals!). One is that it requires more agitation than most developers. PMK is prone to uneven developing, streaking, spots, etc. You have to agitate for the first minute, then every 15 seconds. My agitation procedure is to turn the tank upside-down quickly, then back to upright, then hit the bottom of the tank on the palm of my hand a couple of times to dislodge air bubbles. I do this constantly the first minute, then two times every 15 seconds. Agitate vigorously, not gently.
The other thing is that acids reduce the stain you want from Pyro developers. Do not use stop bath; instead fill and dump the tank with water two times between the developer and the fixer. Most fixers are also acidic. Get an alkaline fixer. I use Photographers Formulary TF-4. Its a great fixer for any film, developed in any developer. Freestyle and B&H both sell the TF-4 fix and they both sell Photographers Formulary's liquid PMK kits.
Wash the film in running water for 20 minutes. The stain intensifies somewhat during the long wash.
thank guys, and Chris, I'm freaking out with your post!!
The point is, for me is easier to handle the Ilford film I think, with Tri X, sometimes too contrasty, sometimes difficult to get shadow details, etc. Always in D76.
Then , the Pyro developers are difficult and danger in use? What's the recomended dilution or which one will give me great tonality, sharpness and details?
Wow.. I'm really impressed.. I think I will make the change, definetely.
