Digital BW, The Print

Kip writes:

> At the risk of displaying my ignorance, can someone
> explain (or point me to an explanation) of the benefits
> of using a tablet over using a trackball (which is
> what I now use with Photoshop) when it comes to
> image work?

Try signing your name with a ball-point pen.  Then try signing it with a
trackball.  That will give you an idea of the difference between a graphics
tablet and a trackball.  I can easily sign my name on the screen with my
graphics tablet, and it looks exactly like it does on paper.

For graphics work, a mouse or trackball is very much like those machines you
used to see in arcades (and also in _Toy Story_), in which you had to
struggle with little wheels to manipulate a claw in order to grab a toy
prize and drop it into a bin.  A graphics tablet is like reaching inside the
machine with your hand and simply picking up the toy you want.

> I've been to the Wacom site, but it seems to assume
> you know what a tablet does, and only talks about
> the differences between their various models.

A graphics tablet is an input device that works like a mouse (most tablets
can in fact be used in conjunction with a standard mouse or trackball,
although not at exactly the same instant).  It's like a small smooth writing
pad on which you can sketch with a stylus that looks and feels just like an
ordinary writing pen (Wacom makes other types of stylus if you prefer a
different feel, e.g., one that feels like an airbrush and so on).  Wacom
tablets are wireless, so the pen is not connected to anything.  When you
hold it near the surface of the tablet, the tablet "sees" the pen and the
cursor on the screen of your PC snaps to a location on the screen exactly
matching the position of the pen on the tablet.  As you move the pen, the
cursor tracks it precisely (within 1/2540 inch).  The tablet is the same
shape as the screen, and each point on the tablet corresponds to one and
only one point on the screen.  Thus, you can sketch, scribble, write, paint,
etc., on the tablet with the pen, and these movements will be duplicated on
the screen.

Tablets are normally absolute; that is, unlike the mouse, placing the pen in
a given position on the tablet always places it in the same place on the
screen (a mouse just moves the cursor relatively, but a given point on the
mouse pad doesn't necessarily always put the cursor at a given point on the
screen).

The pen is sensitive to pressure.  You don't have to touch the tablet in
order to move the cursor; just holding it close (half an inch or so) will
do.  If you touch the tablet, this behaves as though you were pressing the
main button on your mouse and moving it; in other words, touching the tablet
and moving the pen is just like drag and drop with the mouse, only
dramatically more precise.  The pen also has a button you can press that is
the equivalent of a double mouse click; another button is the equivalent of
a right-click (you can configure this behavior differently if you wish).
The top of the pen has an "eraser" that is recognized by some applications
(including Photoshop) so that you can paint and erase just by turning over
the pen, as you would with a real pencil.

Pens are pressure sensitive; most graphics applications (including Photoshop
and Illustrator) are able to sense the pen pressure, which opens up an
entirely new world of graphics.  You can use the pen pressure to vary the
brush size or the opacity of a Photoshop tool as you use it, instead of
having to reset options for the tool.  You can control the sensitivity of
the pen, but it is very precise and it can be made to respond to a feather's
touch; it will tolerate extremely hard pressure as well.

Pens also are tilt sensitive: they communicate information on their position
(the angle they form with the tablet) to the PC, although I haven't seen any
applications that actually use this information, apart from a plug-in
provided with the tablet.  Applications that use it can accurately simulate
things like airbrushing (press harder, and the paint darkens--tilt the pen,
and the shape of the paintbrush changes).

Note that the pen and mouse can both be used on the PC.  If you try to use
both at the same instant, they "fight" (the pen tends to want to hold the
cursor at its absolute position, whereas the mouse tries to move it), but it
does no harm to the PC or the application you are using.  You can alternate
between them if you want.  The pen works just like the mouse for ordinary
applications.  I usually keep the mouse at my left hand, and the pen at my
right (because I am right-handed), and use them interchangeably for most
things; I use the pen exclusively when I am working in Photoshop, though.

> People who use them seem to love them (judging by the
> posts here) and they aren't all that expensive for a
> small one, but I'd be buying one blind at the moment.
> So any advice is appreciated.

You cannot fail to love a graphics tablet.  You'll never be willing to use a
mouse or trackball again once you have the tablet.  The difference is so
dramatic that I've never encountered anyone, anywhere who did not become
permanently addicted to a graphics tablet for graphics work after just
thirty seconds or so of using one.  Whatever you pay for the tablet, you'll
get your money's worth.  Wacom makes the best tablets.