Digital BW, The Print

Hi Kevin,

> If my understanding is correct, the sensors in a ccd do not butt up
> against each other precisely.  There is a small gap between each sensor
> in the array. If the x's below were sensors it would something like
> this:
>
>    x x x x
>
>    x x x x
>
> not like this:
>
> xxxx
> xxxx

Well, though you are right...there are two issues.  One is the spacing
between the photosites is miniscule, compared to the size of the photosite,
and second, some sensors have microlenses over them...which have their own
issues as well.

> I also understand that this slight space between the sensing elements
> creates the "softness" often associated with scanned or digitally
> captured images.

No, that's not correct in my experience.  The "softness" is because of the
properties of the imaging sensors.  Red tends to be the softest channel,
blue next softest and green the sharpest.  This is one of the reasons I've
said that scanning using a single neutral density filter will give you
better (as in sharper...there you go Jerry ;-) scans than scanning using RGB
filters. That is why I believe the Leafscan gives better B&W scans than any
other CCD based scanner.  PMTs do not have this issue, and that's why they
are sharper.

> So, in your experience, is this true?  Also is there an important
> difference in the "spacing" of the sensors produced by different
> manufacturers (foveon vs whoever makes the chips in a Canon/Nikon etc)?

That is something I have not looked into.

Regards,

Austin