Re: Tech Pan

[Andrew Hately <andrew.hately@xxxxxxxxxxxxxx>]

Jim wrote:
> Have several questions regarding 
> Kodak Tech Pan.

I think I've shot about 1/4 mile of the stuff. Its my favourite film.

> Although it has extended
> red sensitivity, I have not been able
> to detect any visual infrared
> characteristics, even using a #25
> red filter.  Using Konica 750 and a #25 I
> get good IR effects.

Tech pan's red sensitivity ends at about 690nm, a little into the infra
red. Konica's sensitivity curve has a peak at 750nm, the response
extending to about 800nm. (Kodak HIE's sensitivity extends well beyond
800nm)

> Has anyone used Tech Pan and produced
> IR effects?  If so...

IR film like skies, yes. 
IR film like haze cutting, more or less, ish.
IR like vegetation, never.

> For the first time two weeks ago I
> used Tech Pan 120 and had very unusual
> results.  The negatives were extremely
> thin, to the point I nearly chucked
> them out. However, I made contact
> prints which looked very presentable.

I always err on the side of overexposure, but yes the overal density is
low compared to conventional films.

> Then, yesterday I printed these negatives
> with wonderful results.  I cannot
> believe negatives that thin could
> produce such rich, detailed, full toned
> prints on #2 paper.  Is this normal
> for Tech Pan?

In my experience (all 35mm) yes.
Similarly its amazing the excellent results that can be obtained from
the dark, dense, fogged looking negatves that XP2 yields.

> My 35mm Tech Pan
> negatives are lighter than other
> films but close to normal.  I am using a
> proprietary developer from Photographers'
> Formulary which is supposed to
> hold contrast down and provide an
> ISO of 30-60 (I used ISO 50 with a hand
> held meter).

After a trying at least ten developers with Tech Pan, I settled on
Pota for best results and for almost as good results but considerably
less hassle, HC110 at 1+200 for 20 minutes, 20C, one inversion every 2
minutes, gives 25ASA ish. Use this as a starting point anyway.
(the flavour of HC110 which gives "dilution B" as 1+31, so this is more
or less dilution B 1 + 5. You might not be aware but two strengths of
HC110 are available.)
 
> My use of Tech Pan only goes back
> about 8 weeks, so my experience is
> limited.  I did try one roll of
> 35mm Tech Pan developed in HC-110 dil F
> with good and only slightly contrasty results.

way too strong! What do you want? Huge grain? :-)

For interesting, very contrasty, available light portraits, try TP at
125ASA with any popular black and white paper developer for 3 mins with
constant vigorous agitation.
You might want to bracket your exposures.

Other developers I've tried with TP:
Pota
  the best but does't keep more than an hour or two once mixed.
HC110
  very good when extremely dilute
Perceptol
  hopeless at all concentrations. Too much Sodium Sulphite.
  Destroys sharpness.
ID11/D76
  not very good.
Dektol
  contrasty! (other paper developers similar)
XTOL
  OK, but not as good as HC110. Improves with diution.
Rodinal
  almost OK at 1+150 or 1+200 but gives disconcerting 
  "edge enhancement effects" leading to patches of the
   picture appearing much sharper than other areas,
   depending on the subject matter, not the focus, etc.
Pyrocatechin based two part developer
  stains too much; thin negative on a dark brown
  base rather hard to print.
Other split developers, some of my own divising
  not worth the bother. Results never as good as HC110.
Tetenal BW Slide kit
  Good results. :-) 6 ASA :-(

regards
the normally silent Andrew.
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End of Infrared-Digest V0 #194
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