Vuescan multiple samples for BW film?

[stevierose]

I apologize if this has already been answered, but, I couldn't find it using the search function. When scanning traditional BW film using a Nikon Coolscan 4000ED and Vuescan, is it worth using the multiple samples option? It is supposed to reduce noise in the scan, but I am not sure that applies to BW film scans. If yes, how many passes is helpful (they increase the scan time a lot).

What about the "Multi Exposure" box, should that be checked?

Thanks!

 

[willie_901]

Typically signal averaging (multipass) decreases random noise by the square root of the number of passes. Two passes reduce random noise by 40% (sq. rt. of 2).

Color and monochrome negatives will benefit equally.

However, if there is not significant improvement, then what you perceive as noise is not actually noise. For instance, grain is not noise. The random noise would be electronic noise from the scanner CCD, the ADC and photon noise (an intrinsic property of light).

When I scan Tri-X with Vuescan and a Plustek OpticFilm, I don't see any benefit with multipass. I assumed this was because grain dominated my perception of scan quality.I have never scanned high-resolution B&W film.

I have seen improvements with color negatives and transparencies.