filmscanners: Nikon Coolscan LS4000 - Peppery scans with Fuji chromes

["Kah Heng, Tan" <kahheng@pacific.net.sg>]

Hi 

I have been fiddling with this scanner for the last half a day since
buying it yesterday. 

Whilst it's ability to see into dark shadows is nothing short of amazing,
and its terrific scanning speed at full res brings a smile to me, I have
been having an extremely annoying problem with what I can only describe
as 'peppery' scans with Fuji slides.

I have posted a section of the actual scans (jpeg cropped full size at
min. compression in Photoshop).

See:

http://www.studioq.com/NOICEVelvia.jpg
(very obvious - the big black spots are dirt; the overall specking is what I am referring to)

and with ICE on,

http://www.studioq.com/ICEVelvia.jpg (less obvious)

Note - these are large jpeg files about 1.5 megs each. The crop is more or less of the same area, same slide.

Having tried Velvia, Sensia II, Provia F, they all have the same outcome - 'peppery'.

Anyone experienced this with their Coolscan 4000?

Now, I had thought that all my slides have super tiny bits of dust on them, but checking them all with a 10x loupe on a Kaiser lightbox, I see no problem with the slides (diff batch, diff films, all well kept, etc). 

Some of the slides were drumscanned before and there is nothing on those scans resembling the specks that I can see here.

I examined the slides carefully at an angle, and I can see that the film base is not 100% clear (isn't this true for all films? Either chromes or negs, colour or otherwise). I took one of the slides and using the loupe viewed it with a specular light source (overhead ceiling lamp) and I could see that at certain angles, there is a 'black speck' effect - i.e., the substrate irregularities (which cannot be seen with a diffused light source like a lightbox) come through as specks. 

I am just wondering if the Coolscan 4000 is somehow 'overscanning' or has a light source that's somehow showing up natural irregularities with certain film bases that's no one needs to see in a scan?

I will do further testing with Kodak slides and other films and negs and post here.

Regards
Tan