Here is a summary of collected wisdom about this developer….

https://sites.google.com/site/jaydefehrsdevelopers/home/510-pyro

http://pictorialplanet.com/advanced_photography/510_pyro.html

http://www.digitaltruth.com/devchart.php?Film&Developer=510-Pyro&mdc=Search&TempUnits=C

https://www.flickr.com/groups/1453269@N25/




I’ve had quite dense negatives with     HP5+     and 510.
At 1:100 and 6.5 minutes, I’m getting a normal looking curve and printing on 2 1/2
filters.
I think Jay was using constant agitation and getting 6 minute sorts of times.
 I was using 30 second agitations and shooting at 320, incident.


You must use an alkalic or neutral PH  fixer with pyro

Kein Stoppbad oder sauren Fixierer für Pyro-Entwickler!!!
Sonst wird der Stain rausgelöst und der Feinstkorneffekt geht verloren.
Intensiv Wässern (min. 3x) und neutralen oder alkalischen Fixierer.
Z.B. den hier oder Selbstansatz
https://www.macodirect.de/chemie/schwarzweisschemie/filmentwicklung/fixierbad/rollei-rxn-fix-neutral-1l?c=102


You get the chemicals here
http://moersch-photochemie.de/moersch/webroot/files/Preisliste_online_Okt2016.pdf

Herstellung: 100 ml Triethanolamin TEA 5 g Vitamin C 10 g Pyrogallol 0,375 g Phenidon
Alle Zutaten so lange im kalten TEA rühren bis keinerlei Klümpchen mehr da sind. Dann 30 Sekunden in die Mikrowelle, bis TEA 70-80 Grad hat. Nicht höher. Ggf. nachmal in 10s-Schritten rein. TEA wird dünnflüssig wie Wasser.  Solange rühren, bis sich alles aufgelöst hat. Wenn der Ansatz dabei kälter als 50° C wird, wieder 10-20 Sekunden Mikrowelle. Eine Nacht ruhen lassen. Fertig ist der Sirup, der ewig -minus 1 Tag hält.
!Achtung! Pyrogallol und Phenidon sind extrem gesundheitsschädlich.  Bei sachgemäßer Handhabung dampft bei 70-80°C davon nichts aus dem TEA aus. Alte Mikrowelle verwenden! Gibt es bei ebay ab 1€.
Feinwaage sollte 0.01 g können. ~ 15€


510-Pyro gives full film speed, or better, so if you normally derate
your film by one stop to ensure good shadow detail, you’ll probably
overexpose for development in 510-Pyro, which leads to dense shadows
and flat negs with normal development.
I recommend that you begin your testing by rating your film at box speed, and finding normal development time for that speed. You might still find that your shadows
are too dense, resulting in flat negs. If so, try increasing your EI by
1/3 stop until you get good blacks in your prints.

I standardize my development at 70F. Pyro developers harden the
emulsion of the film, making higher temps practical, and safe.“


Ganz zu Anfang schreibt Jay, das bei Verdünnung 1+ 100 die Zeiten von D76 für die meisten Filme übernommen werden können.

As a practical matter, I would consider 1:100 the optimum dilution for rotary processing, except in rare circumstances where a more concentrated developer is needed to build contrast rapidly, as in procesing J&C 400 for printing on Azo G2 Canadian paper, or some of the self masking UV processes, where a 1:50 dilution might be more convenient.
To calculate the development time for a 1:50 dilution from the development time for the 1:100 dilution, simply divide by 2.
For those developing roll films in tanks using intermittent inversion agitation, to find the development time for a 1:200 dilution, simply multiply 1:100 time by 2.

I find 1:300-1:500 dilutions best suited to reduced agitation development, and an increase of 20-25% adequate to compensate for the difference between rotary agitation and semi-stand development.

So, if you’re getting appropriate contrast with 8min of rotary development in the 1:100 dilution, but want to see what difference reduced agitation might make, figure 8min X 5 for the 1:500 dilution for 40min., + 25% for reduced agitation for a total development time of 50min for semi-stand development. If 50 min. is more time than you want to dedicate to your experiment, use the 1:300 dilution for 8X3+25%, or 30min.

These calculations are generally accurate, but will vary with class of film, water quality, and other variables, so individual testing is recommended.“

„HP5
For graded paper, 6min, 30 seconds should be close.
 For variable contrast paper, seven minutes or a little longer might be better unless you prefer to increase the contrast filtration on your enlarger to 3.5 or more.
 I have recently tried semi stand development with great results- 1:500 for aobut 45 minutes with three gentle agitations.“

510-Pyro is unique in many ways, not least of which being the fact that it is a single-solution pyro developer. Some formulators of two-solution staining developers have commented that single solution developers are less versatile than two-solution developers, and that single solution developers don’t respond to dilution in a linear way, but neither of these claims are true for 510-Pyro.

The standard dilution of 510-Pyro is 1:100, which gives development times similar to D-76 with most films, but it can be diluted anywhere between 1:50 and 1:500 with very predictable behavior.

Once a development time is optimized for the standard dilution, it is a simple matter to determine a development time for any other dilution. Generally, when calculating a development factor for a developer dilution, an allowance is made for developer oxidation, which varies with development technique; rotary development oxidises a developer more than semi-stand development does, etc..

In practice, one would not use the same dilution for rotary processing as for semi-stand development, so the differences in oxidation are practically insignificant in that case, and it is only when using different dilutions with a common development technique that oxidation plays a role, and even then, the factor is a minor one, and can usually be ignored with 510-Pyro.

As a practical matter, I would consider 1:100 the optimum dilution for rotary processing, except in rare circumstances where a more concentrated developer is needed to build contrast rapidly, as in procesing J&C 400 for printing on Azo G2 Canadian paper, or some of the self masking UV processes, where a 1:50 dilution might be more convenient. To calculate the development time for a 1:50 dilution from the development time for the 1:100 dilution, simply divide by 2.

For those developing roll films in tanks using intermittent inversion agitation, to find the development time for a 1:200 dilution, simply multiply 1:100 time by 2. I find 1:300-1:500 dilutions best suited to reduced agitation development, and an increase of 20-25% adequate to compensate for the difference between rotary agitation and semi-stand development.

So, if you’re getting appropriate contrast with 8min of rotary development in the 1:100 dilution, but want to see what difference reduced agitation might make, figure 8min X 5 for the 1:500 dilution for 40min., + 25% for reduced agitation for a total development time of 50min for semi-stand development.

If 50 min. is more time than you want to dedicate to your experiment, use the 1:300 dilution for 8X3+25%, or 30min. These calculations are generally accurate, but will vary with class of film, water quality, and other variables, so individual testing is recommended.

These variations in dilution and agitation will allow one to process a wide variety of films, to any contrast of which the film is capable, with a range of local contrast, grain and tonalities to suit any creative end, by any processing technique one chooses, without resorting to reformulating one’s developer by modifying the ratios of the A and B solutions, along with dilution, etc., etc., which makes testing an order of magnitude more complex. Having formulated my own two-solution developers, I speak from experience.

510-Pyro is very easy to use, predictable and consistent in its behavior over a wide range of dilutions and processing techniques, despite what the experts might say.

Stand development

This is a popular way of using 510-Pyro, especially when you are either not sure of a developing time for your film or you are wanting a fair degree of compensation of the highlights. The best way I’ve found of using 510 as a stand developer is to dilute the developer in a ratio of 1 to 300 and use it at 24 degrees C. After adding the developer to the tank (no pre-soak) agitate gently for one minute, then let it stand in a 24 deg. C bath until the nine minute point. Agitate again for one minute and let stand for the rest of the time. That’s it! Pour out the developer at 20 minutes and stop with a couple of thirty second water baths, fix with an alkaline fixer.

1:300

Stand develop at 24 degrees C

No presoak needed

Agitate for first minute

Agitate again at the nine minute point

Water stop bath at 20 minutes

Alkaline fix

Jay:

TEA 70ml

Ascorbic Acid 5g

Pyrogallol     10g

Phenidone     0.25g

TEA to         100ml

I began field testing with the intention of fine tuning the developer as indicated by my results. Occasionally, over the last seven years, I’ve been inspired to make a change to 510-Pyro, but testing has always dashed my hopes for an improvement, probably due largely to the fact that my facilities have not been improved, so my work is limited to the same degree of precision it was when I formulated the developer. In the meantime I’ve learned a lot about this developer, often from other users, and I hope to learn more. 

Daniel:

800ml of Triethanolamine heated to 160f.

Add 100g pyrogallic acid,

50g ascorbic acid,

3.75g phenidone..

top off to 1 liter with triethanolamine.

Stir to dissolve, cool & bottle

POTA DEVELOPER

(An alternative to Kodak Technidol developer for Kodak Technical Pan film (or other technical films ).  This formula is useful for other emulsions where very low contrast is desired.  Agitation with TPF is two slow inversions of the tank each minute. Develop between 12.5 and 15 minutes. at 68 F)

Water at 125 F————300 mL

Sodium Sulfite————-30 g

Phenidone—————–1.5 g

Water to make ————–1 Liter  Use cold distilled water

Use immediately after mixing as it deteriorates very quickly after it has been mixed.

This developer was disclosed by Marilyn Levy in „Wide Latitude Photography,“ Photographic Science and Engineering v. 11 p. 46 (1967). It grew out of her researches into the problem of capturing wide variances in luminance (i.e., a long gray scale) on hard, thin, high-resolution films. This formula was devised for solving problems associated with high-altitude aero reconnaissance and mapping. Levy worked at the US Navy’s Photo-Optics Technical Area at Ft. Monmouth, New Jersey, and her formula has been published elsewhere as „POTA.“ Gives images similar to Bluefire HR developer but at significantly lower effective film speed.

Use water heated to 55° (130°F). Mix the chemicals in the order shown, and be sure the sulfite is completely dissolved before adding the phenidone.

This developer begins to oxidize as soon as it is mixed, so mix it just before use. Designed for developing sheet films processed in trays with brush agitation, but works well in small tanks. Experiment with agitation technique as well as time and temperature if your initial results seem streaked or mottled.

POTA-Entwickler

– Er schafft es 15 bis 20 Blendenstufen zu komprimieren, ohne dass die Schatten und mittleren Töne zu kontrastarm werden.

Man kann mit ihm Mikrofilme (CMS 20II) und andere technische Firme (Strichfilme) so entwickeln, dass sie für die normale Fotografie einsetzbar sind.

Der Entwickler muss frisch angesetzt sein, er hält nicht lange.

Einmal angesetzt kann man aber damit in 1-2 Stunden beliebig viele Filme entwickeln.

Interessant ist der Entwickler auch für Grafik Arts Film (Strichfilm) für die GF-Fotografie, wie beispielsweise dieser hier https://www.agfagraphics.com/…/Alliance%20Camera%20CE%20Tec… oder andere Ortho- und Luftbildfilme

Phenidon löst sich relativ schlecht in 50°C Wasser. Anschließend durch Teefilter/Kaffeefilter, sonst gibt es schwarze Punkte.

Rüdiger Hartung gab mir in den Kommentaren noch folgende Tips :

1.
Phenidon:
Es ist vorteilhaft, wenn man vorab eine 4% Lösung von Phenidon in 1,2-Propandiol (1,2-Propylenglycol) herstellt und damit entsprechend dosiert. Damit fällt die Dosierung leichter und das Löslichkeitsproblem wird elimiert.

2. Da POTA nur sehr schwach alkalisch ist, wird die Lichthofschutzschicht oft nicht vollständig entfernt. Es entstehen Schlieren und Wolken.
Abhilfe: Vorwässern mit 2% Waschsodalösung.
Danach und vor der Entwicklung mit Wasser sehr gut klar spülen, um den pH wieder abzusenken.

POTA, consists of only 2 compounds, and is easy to make yourself.  Anchell & Troop state that „POTA-type developers produce exceptionally even density growth over their useful range but have an abrupt shoulder after 8 zones. No further highlight detail is available above that point.“ 

The original objective was to use POTA to test TechPan .

The formula for POTA does remind of D-23 in the sense that it is a 2-compound developer.
The components to make 1 liter of POTA:

• Sodium Sulfite Anhydrous – 30 g
• Phenidone 1.5g
• Dissolve the dry chemicals in 750 ml water at 35°C, then add water to make 1 liter.  Not all of the Phenidone will dissolve, but don’t worry about it.

Use the POTA developer as soon as the temperature cools to 24°C.  The developer oxidizes quickly after mixing, and typically it’s recommend that you use it within an hour. 

You canweigh out the dry ingredients for each 1 liter batch and put them in a ziplock bag so that you can mix them when needed. 

50 g of Phenidone is $12, and 1 lb of Sodium Sulfite is $6.50.  That’s enough to make 33 liters of developer, which would develop up to 132 rolls of film, for a cost per roll of less than 15 cents. 

Anchell and Troop also provide another formula for a low-contrast developer called TDLC-103:

• Metol – 1g
• Sodium sulfite – 5g
• Sodium Bicarbonate (baking soda) – 10g
• dissolve to make 1 liter

POTA Development TIMES (all at 24°C)

Kodak Technical Pan – 12 minutes

Eastman 5363 – 12 minutes

Kodak 2378 – 11 minutes

Kodalith Ortho Type 3  – 11 minutes