Developer for FP4

**Bill_1856** · 17-Dec-2008, 17:42

I would appreciate comments about using FP4 sheet film and tray developing in 1) PMK, or 2) Diafine. Thank you.

**John Berry** · 17-Dec-2008, 17:46

3) pyrocat

**Richard Wasserman** · 17-Dec-2008, 17:55

I'm another vote for Pyrocat. PMK is also nice, but by a small margin I prefer Pyrocat. I have no experience with FP-4 and Diafine.

**timbo10ca** · 17-Dec-2008, 17:58

py-ro-cat-HD!!!!!!

**Ken Lee** · 17-Dec-2008, 18:09

ditto

**scrichton** · 17-Dec-2008, 18:19

Diafine all the way. With FP4 rated at 200, or 160 for highlight bloom. It's a real winner. Try running a 120 film as a tester.

Plus Diafine also has the major advantage of the 'as long as it's over 3 mins' in each bath. Which lowers the confusion in the dark.

I have shot a lot of it on flash at 250 on an old TLR and the tonality in Diafine is great. Although it probably depends on the application you are thinking about.

**Blueberrydesk** · 17-Dec-2008, 19:47

another vote for pyrocat-HD.

**Bill_1856** · 17-Dec-2008, 21:41

Why Pyrocat instead of other Pyro developers? What ISO? How does it last? What is the difference between Pyrocat and Pyrocat-HD? Etc.

**Ken Lee** · 18-Dec-2008, 05:20

Many of us have had good experience with Pyrocat HD. This is anecdotal evidence, you might say.

Then, there is the theoretical evidence, which is expressed in carefully controlled sensitometry tests - which demonstrate that the combination is very linear in responding to light, and responds very nicely to changes in developing times. Compared to other films, and to other developers.

Pyrocat is an abbreviation for the key ingredient in Pyrocachetin-based formulas, and Pyrocat HD is one such formula. There are other "pyrocat" formulas. there are also other Pyro formulas, which use Pyrogallol, a different ingredient.

See http://unblinkingeye.com/Articles/PCat/pcat.html for the whole story.

**sanking** · 18-Dec-2008, 08:30

Bill,

Pyrocat-HD is the original Pyrocat formula. Like PMK it comes in two stock solutions that must be mixed in water to make a working solution. With Pyrocat-HD the A Stock solution is made up of the reducers pyrocatechin (catechol) and phenidone, sodium metabisulfite (preservative) and bromide (anti-fogging agent), and can be mixed in either water or glycol. Stock B is a 75% potassium carbonate solution. With most films it gives very low general stain and a brownish black stain. It was designed for tray development and for development with minimal agitation, but also works well in tubes with rotary development.

Pyrocat-MC is a newer formula and was specifically designed to give slightly higher accutance in rotary development, and to give lower general stain with long developments times of the type that would be needed for N+ development for alternative printing. Stock A is made up of the reducers pyrocatechin, metol and ascorbic acid and must be mixed in glycol. Stock B is the same as for Pyrocat-HD.

Sandy King