Nancy,

I have had really good luck in scanning shells and will gladly pass on what
I have learned and what I was taught by Bill Frank of Jacksonville.

First, I hope you have a good scanner.  I found the Visioneer to be great
for scanning shells.  I use the 300 dpi setting for most of my work, unless
the shell is really small, then I kick it up to 600 dpi and set an initial
frame really pretty tight on the shell so I can blow it up and still have a
good image.  If you leave the cover off you will pretty much get a black
background.  It will have some flaws and light areas, unless you scan in the
evening with the lights out.  Who watches that much TV anyway.

Recently I scanned a lot of nerites and many were black -- kind of negating
the use of a black background.  In this case I uses a piece of blue
construction paper.  One piece cut and taped to form a circle about one inch
high, then another to set on top of the circle (with the shell inside).  The
trouble with this is you end up with a shadow.  This looks okay unless you
combine two images (dorsal and ventral) and then the shadow may not quite
fit properly.  What I did was put in an entirely new background with
Paintshop Pro (a great program).  There are many other programs that will
perform similarly but I really like this one.  There is no easy way to do
this as the automatic fill functions almost always cut into the image.  I
basically go around the image with a pen tool and put in the new color, then
block out the large areas.

I have scans I can send you that show some of this and would be happy to
answer any questions.

Tom