[LargeFormat] TriX HC-110 development time

[Richard Knoppow]

----- Original Message ----- 
From: "David Galway" <design@wizbot.net>
To: <largeformat@f32.net>
Sent: Tuesday, August 12, 2003 5:39 AM
Subject: RE: [LargeFormat] TriX HC-110 development time



Second set of questions:

I looked on the Kodak site last night for info on how to mix
Kodak Rapid
Fix w/hardener for film. Couldn't find anything on anything
but
developers ... am I looking on the right site? Are there any
other sites
that might have this info?

Also, I was in the habit of presoaking my 5x7 HP-5 for a
minute before
developing ... should I be following the same practice with
8x10 Tri-X
Pan?

---

It's been a while since I got my hands wet, so to speak, and
I have a
cache of three to four year old liquid and powdered
chemicals in my
basement. Does anyone have a general idea of shelf life of
the
following:


Kodak Rapid Fix & Hardener (liquid)

Kodak Selenium Toner

Dektol (powder)

Hypo Clear (old bags have no expiry date, current bags do)

Ilford Rapid Paper Fix (liquid)


regards
David Galway

  Kodak Rapid Fixer with Hardener should be mixed one part
concentrate to three parts water for film and one part
concentrate to seven parts water for paper. The hardener can
be added or not as you choose, but if you use it, it should
be added to the concentrate before diluting it.
  The shelf life of the unopened concentrate is indefinite.
My experience is that it will last about two years before it
begins to decompose. The decomposition is obvious because
there will be a deposit of elemental sulfur in the
container.
  Life of the mixed solution is about two months in a closed
container and about one week in a tray.

  Kodak Selenium toner concentrate also has an indefinite
life in an unopened bottle. The mixed toner probably has a
life on the order of three months but I've used toner that
was much older than that. The test is whether is tones.

Dektol powder in container has an indefinite life.
Supposedly, the metalized plastic lined bags are completely
air and moisture tight but in practice they seem to leak. I
would guess the reliable life is around two years but could
be much longer. If the powder is not white when the bag is
opened the stuff has oxidized and should be tossed.

Hypoclear is a trade name, do you mean Kodak Hypo Clearing
Agent? If so the answer is the same as above for Dektol. The
life of the mixed stock solution is give by Kodak as three
months. The working solution will oxidize in 24 hours. The
sulfite oxidizes to sulfate. While sulfate will not harm the
negatives or prints it has much less power to displace
thiosulfate ions than sulfite does, so the solution becomes
much less effective.

  Ilford should have some data on shelf life on its web
site. At a guess its about the same as for Kodak liquid
fixer.

  All processing solutions are perishible and expendibles.

  I am not convinced that there is any advantage to
pre-soaking film except where some processing method is used
that does not insure uniform application of the developer to
the film. Its common in drum processing and is recommended
for processing several sheets of film in trays where there
is a problem with the film sticking to other films.
  Some films contain wetting agents and other additives
which are washed out in the pre-soak.
  Development times will be affected by the pre-soak since
they swell the emulsion and overcoating, and saturate it.
That will change the diffusion time of the developer into
the emulsion, and, consequently, the "induction" time, i.e.,
time for the first appearance of the image. Where the
developer has an overall long development time the effect is
less since the induction time is a smaller fraction of
overall time.
   I would not resort to a presoak unless you have problems
with uneven development from developer application or from
air bells which can not be gotten rid of by simply knocking
the tank.
   This does not apply to Jobo or other processors where the
machine manufacturer recommends a pre-soak.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com