A point that's not being made so leading to misconceptions it the format/negative size. Stand and semi-stand development can work well with larger formats and you do get better adjacency effect which means prints appear sharper. But with smaller formats it can look awful.
I use Pyrocat HD with HP5 and at the recommended 1+1+100 dilution with inversion agitation and I get the benefits of good edge effects and micro-contrast which are inherent with this type of developer containing Pyrocatechin or Pyrogallol anyway, due to the tanning effects of the developer.
In making the choice of taking the edges effects to greater extremes has to be balance with the intended uses of the negatives, for instance a 35mm negative which is going to be enlarged will give images where the edge effects look like unwanted artefacts, there may be cases where they contribute to an overall graphic effect. When the extreme acutance developers were available (Definol, Acutol-S, Hyfin, Kodak HDD etc) there were so striking grapgic usually quite high contrast images made using 35mm films - these developers weren't as fine grained as Pyrocat either.
Where this technique comes into it's element is Large format where there's little enlargement and particularly contact prints. I'm refering to the edge effects thouh here.
Steve I'm not sure how much of this is due to the nature of the Pyrocat HD developer itself rather than the dilution, like you I've been using Pyrocat for around 10 years with a variety of films although mainly Delta 100 & 400 and HP5 LF.
Originally Posted by Steve Sherman
I'm assuming you mean contrast when you say environmental conditions and my experience is that Pyrocat can copes particularly well with extremes of contrast giving negatives that are remarkably eay to print. That's shooting in the extreme high contrast midday sun in Turkey &n Greece though to the dull overcast low contrast light we often endure in the UK.
Two interesting article on Pyro developers by the same author one in the late 30's and the second "Modern uses of Pyro developers" just after WWII extol the virtues of these developers which had by then largely gone out of favour, he talkings about a more modern dilute approach.
In thinking why is a staining developer like Pyrocat so valuable we need to realise the developed negative has two components a silver image and a dye stain im age. We don't develop the silver image to as a high a Dmax as with a conventional developer and the stain image is more akin to a Chromogenic film like XP2. The benefits of XP2 is a long tonal scale and the ability to shoot at various speeds with the same development time.
So when we shoot in a low contrast situation and develop im Pyrocat (or any other Pyro staing develop) we predominantly use the silver component in printing or scanning, in a high contrast situation the stained component becomes far more important in the highlights and mid-tones the staining & tanning becomes greater and the result is no blown out highlights. Of course this is going on at a local level as well.
I use Pyrocat HD and 2+2+100 and continuous agitation to process my 10x8 negatives and I still get excellent edge effects and micro contrasts so concluded some years ago it's the attributes of the developer rather than agitation or dilution.
I'm not disagreeing that you can't increase this slightly with your extreme dilution minimum agitation technique