Re: Rollo pyro-sodium metaborate/ plus pyro and roller transport

Carl Weese (cjweese@wtco.net)
Tue, 02 Jun 1998 03:33:35 -0400

Jamie,

"The Book" on pyro already exists, and is called "The Book of Pyro", by
Gordon Hutchings. Available at PhotoEye, LightWorks, and other places.

"Rollo" is a variation on PMK pyro meant especially for rotary
processing (and not covered in the Hutchings book). If you are
developing in a tray, the standard PMK formula is preferable. Rollo
contains ascorbic acid to serve as both co-developer with the pyro and
metol, and an anti-oxidant to combat the rapid oxidation that happens to
pyro in rotary processing. Rollo simplifies rotary processing because
regular PMK requires several steps--like developing in two stages to
keep the solution fresh--that the non-oxidizing version gets rid of.

In a tray, rollo functions like a "non-staining pyro" formula, producing
extremely high resolution negatives made up mostly of silver with very
little stain. Since the main reason to use pyro with modern films is to
obtain a negative with lots of stain and relatively little metallic
silver, it isn't recommended for tray use. If you are using it in a tray
you are probably getting sharp and contrasty high resolution negatives,
but not much staining. Switch to regular PMK and you will see much less
silver density and much more lovely proportional stain. (I haven't
tested Verichrome pan, but I *expect* this will be the case)

The metaborate is used to foster the formation of the proportional
stain. Any alkaline solution would do, including used pyro developer,
but using a fresh bath of dilute metaborate is a good way to maintain
consistency. A long wash--20 minutes--also should be used for best
staining effect.

Roller-transport processing usually requires high energy, concentrated
developers, which pyro is not. I wouldn't expect it to be a good option,
but haven't tested it.

(PMK and the "rollo" variation will both be covered in detail concerning
their use in making negatives for platinum printing (and "crossover"
negatives that print well in either platinum or silver) in "The New
Platinum Print" book by Richard Sullivan and me, to be published this
summer.)

---Carl