Periodic soft banding in grain

[pmiles]

Hi
Silverfast Ai 6.0.1r42 & 6.0.2r40
Polaroid SS120 scanner (using firewire)
OS10.2.3

Dear Silverfast

1-When scanning 'HDR Grayscale' @ 4000dpi (35mm film) I consistently get alternating bands of softly and clearly resolved grain sharpness across the whole negative.

2-These bands of softness are very regularly and closely spaced down the length of the scan.

3-The bands go right across the width of the frame.


I initially thought this was a hardware problem with the scanner. However the same negative scanned consecutively by Silverfast and then PCI 5.6 (PolaColor Insight) shows clear banding for the Silverfast software but no sign of banding for PCI software.

I much prefer that we use Silverfast. Can you help me sort this problem?
Do you want me to send copies of the respective files (Silverfast / PCI)?

Peter Miles
Photography Technician
Massey University

[LSI_Muenier]

Dear Mr. Miles,

please check if in SilverFast's Options dialog the interpolation
mode is chosen to be "Anti Alias".

If so, please send me your sample scans to
martin.muenier@silverfast.com
so that I can inspect them.

Thank you very much.

Martin Muenier

[ilyons]

Martin,

please check if in SilverFast's Options dialog the interpolation
mode is chosen to be "Anti Alias".

I've seen this particular response a few times now and wonder why you think it's relevant. If we scan at 4000ppi (i.e. the optical resolution of the scanner) and don't scale the image why would the choice of Interpolation method make any difference?

Ian

[pmiles]

Hi forum
I hope you find this useful, Thanks Martin (silverfast) for your help.

----------
Hi martin

I have been trying the Anti Alias interpolation.
This has stopped the periodic soft banding issue I was having.

Can you please explain the intention of these two different interpolations methods?


Regards
Peter Miles

[pmiles]

I've had a reply from Martin regarding the intent behind the two interpolation methods.

Martin, I hope you don't mind me posting your reply here but I think other users might find it useful.

Regards
peter Miles

Martin wrote....
Dear Peter,

the standard interpolation is faster and good enough if you do not have too much noise (or grain) in your scans,
the anti alias interpolation is slower but does not produce artefacts from noise.

Best regards,
Martin Muenier, LaserSoft Imaging AG