Graphics Programs Reference
In-Depth Information
ive point-and-shoot cameras. Larger sensors are more light-sensitive and produce higher
image quality than smaller sensors.
However, in general,
for a given sensor size
, the more pixels the higher the image quality.
Photoshop will do some very useful math for you with respect to image size, but I thought
it might be worthwhile to run through an example to help you understand what Photoshop
is telling you in the
Image Size Window
shown in
Figure 24
.
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Math Warning! If you are math-averse you can skip this brief example. Photoshop will do
the work for you. This is just intended to show the process if you are curious.
For an image captured with my 15-Megapixel Camera, if I want to print an image at a res-
olution of 300 pixels per inch, it will be 4752 pixels divided by 300 or 15.84 inches wide.
Likewise it will be 3168 pixels divided by 300 or 10.56 inches high as shown in
Figure
24
. If I change the resolution, Photoshop will calculate the related size of the image. If I
change the size of the image, Photoshop will tell me the resolution based on the number of
pixels available.
If I want to print a smaller image such as 8 X 10, I first have to crop the image to the correct
aspect ratio of 4:5. This will eliminate a significant number of pixels. Even after cropping
