Re: Development of Konica 750

[Ben Kreunen <ben@xxxxxxxxxxxxxxxxxxxxxxx>]

At 05:08 PM 8/2/00 -0700, you wrote:
>I have noticed that my Konica 750 contacts do not produce a good, crisp
>white in the labels and frame numbers along the film rebate when the
>contacts are printed for minimum time to produce maximum black.  On the
>film, the frame numbers are a middle gray.  This has been true for me
>with both Rodinal and Xtol development, and I thought it was just a
>property of Konica 750 film.

You've actually got things around the wrong way.  Expose for the whites in 
a print and adjust the contrast for the blacks. What you have described 
here is overexposing a print on a paper with too low a contrast. I wouldn't 
adjust your processing until you get the printing right (unless you want to 
use this particular paper)

>Then on a recent roll I increased development time because I had a hunch
>that the subject would produce low contrast, even in IR; and for this
>roll the film labeling is nearly white in the 'properly printed'
>contacts.

The two are completely separate things. The frame numbers are put on with a 
fixed exposure. If you increase your processing then they will be lighter 
in the print.  What your subject looks like depends on a lot of other 
factors (exposure, lighting conditions, subject matter etc...) which have 
absolutely nothing to do with frame numbers.

>Since the usual benchmarks for zone system exposure and development are
>not available for B&W IR photography, I'm thinking that the film rebate
>may be a good indicator for development.

If the film rebate picks up density then it is a good indication that you 
are overprocessing.  If you have a black part of your image next to the 
edge of a frame and you have bracketed exposures then you would pick a 
frame around the point where the black part of your image began to pick up 
some density compared to the film rebate.  This will give you the shortest 
exposure (best highlight detail) which has the best shadow detail BUT it is 
not necessarily an indicator of good processing. This will depend on what 
the highlight detail on this frame is like as well.

Film: Expose for shadow detail (of final print), process for highlight detail
Print: Expose for highlight detail, contrast for shadow detail.

Forget about the appearance of frame numbers, your image is the only thing 
that matters.

If you're trying to get a direct comparison between contact prints and 
enlargements, remember that contact prints will have a lower contrast than 
enlargements.


Cheers

Ben

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