From: KEMAL DELIC (deli@swipnet.se)
Date: 03/26/01-01:39:15 PM Z
Sandy,
If you print from the slide film, you are right. Dark slide corners
combined with weak corner light of the enlarger lens will give you
lighter negative corners, or darker final positive corners.
But, if you print from the negative film, you are wrong.
Light negative corners combined with weak corner light of the
enlarger lens should give you the corners with more "normal"
density on the positive film. THEN YOU REVERSE ALL THE
TONES in the reversal bath to get a negative with corresponding
tones. With this negative you can make a final positive with
"normal" corners.
My negatives made with Liamīs reversal process donīt have dark
corners and are dust free.
Regards,
Kemal
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----- Original Message -----
From: Sandy King <sanking@hubcap.clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, March 27, 2001 4:27 AM
Subject: Reversal Negatives, was Direct negatives from slides
> Unfortunately there is a problem with reversal processing that has not
> previously received much attention. The problem is not in Liam's system,
> but in reveral processing per se. Consider the following.
>
> 1. Virtually all lenses deliver less light at the corners of the image
than
> in the center. This is true to some extent with all lenses but the
> differences can be especially great with wide-angle lenses, less with long
> focus lenses.
>
> 2.Use of movements on cameras that allow adjustments such as shift, swing
> and tilt can further increase the differences in illumination at
different
> corners or sides of the film plane.
>
> 3. When we make a print the lack of even illumination that was caused by
> the taking lens is compensated for to a considerable extent by the
> enlarging lens, which also delivers less light at the corners and edges
> than in the center. In the course of making a print we typically correct
> by dodging and burning in other parts of the image to correct for
uneveness
> of illumination.
>
> 4. The final densities of a reversal print are based on the initial
> exposure (and of reverse order), in which the uneveness of illumination of
> the camera lens and enlarger lens work together (rather than cancel each
> other out as in printmaking). The result is that unless some doding or
> burning is done in making the initial exposure the reversal negative will
> in most instances increase the difference in illumination between the
> center and the corners.
>
> What I have observed in printing reversal negatives made by me and by
> others is that they require considerably more work (dodging, burning) to
> print correctly than in-camera negatives.
>
> Sandy King
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