two bath developer with speed increase ??

hi,

 

I'm looking for a recipe for a two bath developer that yields a

genuine speed increase ( from box speed onwards )...

 

any suggestions? its for tri-x ( and other 400iso films. )

 

 

thanks.

Diafine gives what appears to be a speed increase with Tri-X. (Not sure if you'd call it a "genuine" speed increase, though.) A formula for a Diafine-like developer can be found at http://www.apug.org/forums/showthread.php?t=11827&highlight=diafine+formula

If you can get a copy of "The Darkroom Cookbook", there's a recipe for homebrew "Diafine" in there. That will give you at least a 1 stop push.

Why do you want a two bath? If you insist, Paterson's FX50 gives the biggest speed increase I've ever seen: true ISO close to +1 stop (i.e. not 'pushed') for Ilford HP5 Plus = near enough ISO 800. But I'd stick with DDX or Microphen. Same speed; easier.

 

Cheers,

 

Roger (www.rogerandfrances.com -- recently revised)

You may want to try Tetenal Emofin. You'll get two useful stops or more with less grain than N with many developers. The neg will be low contrast. I don't know what you mean by "genuine," but this may be as close as you'll get.

Try Diafine. The manufacturer recommends an ISO of 1600 for Tri-X. I prefer 1200-1250. If there's a true speed increase it's probably in the neighborhood of 500-600. But the negatives don't look right exposed that way. So 1000-1600 works better with Diafine.

 

It's no more troublesome than a single bath developer. Just different. The usual factors of time, temperature and agitation are less critical with Diafine. You can be off a few minutes here or there, several degrees cooler or warmer, it won't matter. Agitation makes no difference in Part A - agitate normally, continuously, doesn't matter. Part B requires careful agitation, tho'.

 

Diafine produces unique looking negatives and isn't suitable for a wide range of films. It's best with Tri-X, altho' I also like it with Pan F+ (at 50) and Delta 3200 (at 1600). You don't always get a significant speed increase, but sometimes the results are very good in other ways. I think it's awful with T-Max films but some folks like it.

 

Microphen will produce more "normal" looking negatives and is excellent for pushing Tri-X and T-Max 400 to 1600. An Ilford rep reported that HP5+ yielded a genuine ISO of 500 in Microphen. That's a pretty significant speed increase, considering that most of the time we're taking great liberties with the concept.

Dear Lex,

 

The Ilford rep was being conservative. Ilford's own technical people report ISO 650.

 

Cheers,

 

Roger

Two bath developer, WHY ? Modern single part formulas are so much more technically advanced than that (two part) concept. Additionally, it takes so much more time with less image quality.