Digital BW, The Print

> From: Bob Frost
>
> Mmmm. My 'understanding' of this was a result of making a 4x4" image of
> black and white lines one pixel wide - so 40x40 pixels
> alternating black and white lines, 10ppi.
>
> If I upsample this by 10% using nearest neighbour interpolation to keep
> things at their simplest, i.e. make it 11 ppi with resample checked, an
> extra white line is inserted every 10 lines, giving a band of
> white 2 pixels
> wide every 10 lines.
>
> If I upsample by 10% using another method such as bicubic, an
> extra line is
> still inserted every 10 lines, but some lines on either side are
> now altered
> in color. This makes it harder to see the extra inserted line,
> but it can be
> seen. It even seems to show the different effect of bicubic smoother and
> sharper.
>
> BUT, whatever method I use, the end result is banding of varying
> width and
> sharpness every 10 pixels. How does this square with what you are saying?

Sure, if you use Nearest Neighbor. But I'm under the impression that the
various stairstep upsampling actions that people gush about use repeated
iterations of Bicubic.

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Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...