From: Peter Marshall (petermarshall@cix.co.uk)
Date: 02/27/02-05:13:21 PM Z
> Just a comment or two, Jack-the bi-cubic interpolation is fine, provided
> it's done in miniscule increments (like 1% at a time) which makes it
> enormously time consuming. I'm a big fan of Genuine Fractals, mostly
> because I can store a print-ready negative in one file and open it to
> whatever size I need to print and get exactly the resolution required.
> I
> haven't experienced it taking any longer than opening any other
> format-and
> it's certainly faster than the incremental bi-cubic adjustment. Of
> course,
> I'm usually off tending to something else while my files are opening.
> These
> days I'm mostly getting more Girl Scout cookies. . . .
>
> And, okay, I admit it-I don't run any 4x6 foot negatives.
>
> Go easy,
> John
>
I'd just add that as well as the stepwise use of bicubic interpolation, it
is often worth looking at the results of other algorithms, particularly
the Lancos and Mitchell ones. One piece of software which can use these is
FotoCanvas Lite which is the image editor that comes with ACDSee. Both run
pretty fast and would help your waistline. I've found that several other
image editing programs do a job than Photoshop's simple bi-cubic.
Sometimes the fractal software does a better job, but more often it seems
to be beaten by other methods.
The problem with the bicubic appears to be in building up artefacts (which
I think the stepwise approach avoids). Of course no interpolation provides
detail that was not present in the original.
Peter Marshall
Photography Guide at About http://photography.about.com/
email: photography.guide@about.com
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