- [Instructor] When we look at a photo,
a graphic, a video clip, or any kind of design work
created using a computer, we see a whole image
and interpret it using our usual faculties
for understanding composition, context,
color, and light as a whole.
This isn't the way the image is formed, though.
In reality, we're looking at a number of single dots,
which collectively form the image.
These dots are referred to as pixels,
which is an abbreviation of the words picture and element.
Computer screens have them,
TV monitors and projectors have them,
and software allows you to work with them.
When you make adjustments to visual elements using software,
you're making adjustments to pixels.
There are many ways
of approaching the adjustments you'll make,
and the results can vary wildly.
But everything you do
will ultimately modify individual pixels.
If you make an image brighter,
you'll actually be making the pixels brighter.
If you stretch an image, blur it, sharpen it,
change the colors, or add a glow,
the result of the adjustment
is not produced by modifying a picture.
You're modifying the pixels in the picture.
This idea of using dots to form images
is far from new.
The pointillists had the idea in the late 1800s.
Each pixel has values associated with it.
These include an aspect ratio, color values,
and a position in the image,
measured horizontally and vertically
from the top-left corner.
I find many controls available in creative applications
make more sense when I keep in mind
the adjustments I'm making are per pixel
rather than for the image as a whole.
Understanding this distinction
helps explain the differing results
and the problems you might encounter with parts of an image.