This month let’s take a little time to understand
more about digital image resolution. There are many myths
floating around, and some of you might be confused. This
newsletter will help you understand more about how the
Imagener enlargement engines (in Imagener and YottaPrint)
affect images processed through them.
Digital images such as graphics on a web page or photos
from a digital camera are all made up of pixels -- “picture
elements” -- tiny units of picture information.
Every image on your computer is represented by a colored
grid of pixels.
Digital cameras records pixels, scanners convert images
into pixels, photo-editing software like Imagener manipulates
and adds pixels, a computer monitor displays pixels,
and a printer prints pixels onto paper.
Computers use pixels to measure instead of inches. Printers
use inches to measure instead of pixels. This is important
because what you see on the screen can be very different
than what prints out on your printer.
Pixels transform into inches through what is called “resolution,” --
the number of pixels per square inch on a computer. Resolution
allows you to transform pixels into inches and back again.
Two resolution definitions are often used in place of
one another. Pixel resolution is the size (in bytes)
of your image or its appearance on a computer screen.
This number is tied directly to how big your image is
on your hard drive. The byte-size of the image file is
directly proportional to the pixel count and its size
on your computer screen, which simply displays all the
pixels in a fixed one-to-one grid.
Embedded resolution is different. Embedded resolution
tells your printer how far apart to spread the pixels
in a printed image. It determines how "fine
grained" the printed image will look. It is completely
independent of the pixel count (file size) of the image.
A high-pixel-count image can have a low embedded resolution
or vice versa. Given the same pixel count, a high
embedded resolution will result in a smaller printed
image (the pixels are packed together more tightly),
and a low embedded resolution will result in a larger
image (the pixels are more spread out).
For example, these two images are exactly the same size
on your computer screen and they look the same, but they
are very different. The image on the left has an embedded
resolution of 230 dpi (dots-per-inch). The image on the
right has an embedded resolution of 600 dpi. The image
on the right will print out much smaller than the one
on the left.