Digital BW, The Print

Paul, you wrote:

> I have not been following this thread, but wanted to add that
I've been
> using "multi-pass" scanning since the days of my old HP 4c
flatbed.  The
> Photoshop "apply" function allows you to merge any number of
single pass
> scans easily.
>
> While this technique reduces noise by averaging the random
fluctuations, I
> have also noted more than occasional sharpness losses in every
scanner I've
> used, from the flatbeds to the Nikon 8000.  Some if not most of
it appears
> to come from the negative expanding slightly from the heat of
the light.

What kind of carrier are you using on the 8000 ?  If it is a
glassless carrier for MF then it is more likely that the film is
just not in focus anymore at the second pass. Even in a single
pass it happens if no autofocus is done just before the actual
scan. I don't think the leds produce enough heat to get film
popping or something alike, it is just the carrier and the very
limited DOF of that scanner that makes it happen.

There's another reason to do an autofocus just before scanning.
According to Paul Graham the leds start to burn directly at the
scan phase, they get warmer while travelling and by that their
light output increases. He noticed that on equal density areas
there was a change in the image data as a result of that.
Unlike the Epson 3200 the Nikon 8000 doesn't warm up before
scanning. For that reason Paul starts a scan and breaks it off
immediately and then starts it up again, so the leds are already
warmer at the beginning of the actual scan. I have not had any
film image that is so critical but I thought that an autofocus at
least makes the leds a bit warmer. The gradation effect of the
cold leds will of course be limited by multi pass scanning.

It is really time for a NikonScan upgrade.

Ernst