Vuescan 4870 Batch and Multipass

  • Thread starter Thread starter MW
  • Start date Start date
M

MW

Hi, does Vuescan support batch scanning with the Epson 4870? I can't
see that it does.

How about multipass? I tried the scan to file and wanted to see if
multipass scanning from the raw file would result in better shadow
detail. Any comment?

Thanks,
Matt
 
MW said:
How about multipass? I tried the scan to file and wanted to see if
multipass scanning from the raw file would result in better shadow
detail. Any comment?
Click to expand...

You can no multi pass scan from raw. The noise is already present in
the raw file.

The noise reduction with multi scanning is baesed on the fact that
noise is different in each scan. This requieres physical scans.
 
You can no multi pass scan from raw. The noise is already present in
the raw file.

The noise reduction with multi scanning is baesed on the fact that
noise is different in each scan. This requieres physical scans.
Click to expand...

But his alignment will be perfect... ;o)

Seriously though, one cautionary note: *Multi-pass* multi-scanning in
VueScan is just a very time consuming and complicated way to blur an
image - and still manage to preserve most, if not all, of the noise!

The only way to get any meaningful noise reduction with multi-pass
multi-scanning is to *sub-pixel* align each image before averaging
them out. And even then the sub-pixel alignment will introduce slight
blurring so many more scans would be needed to achieve a comparable
effect to a smaller number of true single-pass multi-scans.

Don.
 
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