User Guide

Academic Courseware: Chapter 1
Joyce Ryan
7
• the requirements of any systems that will process the animation
when you are finished with it in Corel Painter,
• the final delivery medium of the animation (video, film, Web, CD,
QuickTime, AVI, etc.).
Dimensions or spatial resolution
Bitmaps have two dimensions. They are grids containing picture
elements (pixels). The dimensions of a bitmap are described by the
number of pixels the bitmap is high and the number of pixels the
bitmap is wide.
spatial resolution = width x height
The spatial resolution of a bitmapped image is based on how many
pixels in the grid make up each unit of measurement. In Corel Painter,
you are working in pixels per inch (PPI). In other words, if you have a
one-inch grid, how many pixels is this grid broken up into: 72, 96, or
maybe 300? Which would look sharper and have more detail, the 1”
grid described by 76 pixels or the 1” grid described by 300 pixels?
Compare resolution and zooming
Look at an image file and note its resolution. Let’s say it is 720
x 486 pixels and has a resolution of 72 ppi. Zoom in on it
200%. It looks twice as big, but it is still only 720 x 486
pixels. You have made the pixels of the grid look bigger, but
you have not added more pixels to the grid, so the resolution
has not increased.
Increase screen resolution
Increase the resolution of your monitor to see what happens.
The icons on your desktop look smaller. Why?
Color resolution
A bit (binary digit) can describe two states: on and off, black and white,
0 and 1, etc. If 1 bit = 2 colors, 2 bits give you 4 colors, and 8 bits give
you 256 colors. That’s 2x2x2x2x2x2x2x2 = 256, or 2 to the power of 8
(2
8
). At 24 bits of information, you have over 16.7 million colors to
work with. Each pixel is made of three components: Red, Green and
Blue, or RGB for short. We have 8 bits of color for each component, or
256 levels of Red, 256 levels of Green and 256 levels of Blue. Multiply
256 x 256 x 256, and you get 16,777,216 colors. You now know why
Corel Painter and other software programs display RGB in values of 0 to
255. If each of the three RGB colors has 8 bits, the image needs 24 bits
The PPI doesn’t tell you
anything about the actual size of the
grid.
PC’s typically default to 96
ppi, and Macintosh® computers
default to 72 ppi. Television sets
default to 72 ppi. A liquid crystal
display (LCD) screen may be set
brighter than a cathode ray tube
(CRT) one. Apple® computers
typically default to a brighter screen
gamma than PC’s. When designing
for the Web, developers typically test
their work on both platforms. If you
are working in video, you will also
want to look at your work on a video
monitor.