P3D Re: Dodging and burning

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Tue, 25 Nov 1997 10:42:59 -0700
>From: Paul Talbot <ptww@xxxxxxxxx>
>Subject: P3D Re: Re: Uniqueness of the original, II

>[Dodging and burning prints:]
>> I would think you'd be almost certain to introduce mismatches
>> between the two views.)

>I don't have any experience doing this, but dodging and burning
>are used to selectively lighten or darken parts of a print.  For
>me, overall exposure (and color) differences between the two images
>of a pair do not interfere with stereo viewing.  The brain seems
>perfectly willing to average the different exposures when viewing
>in 3D.  

I can see how that might work for a difference in exposure across the
entire print, but since dodging and burning just affects *parts* of the
print, I would think that if the specific parts affected don't match
up fairly closely, your visual system might pick up the local differential.

Does anyone have "rule of thumb" numbers for the number of density steps
"typically" available on a black and white print? A color print? A color slide?

Thanks.
John R


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