High & Low Resolution
High
If there are lots of pixels per inch, the resolution is high.
Prints are often made with a high resolution, such as 300 ppi.
On such a print, the pixels are tiny.
There are many of them squeezed into every inch.
Low
If there are few pixels per inch, the resolution is low.
A billboard may have a resolution of only six pixels per inch.
If you looked at the billboard from one foot away, you could see
these enormous pixels.
But, because billboards are viewed from a distance, more pixels
per inch are not needed.
A low resolution is sufficient.
Lots of Pixels Per Inch - Higher Resolution
Few Pixels Per Inch - Lower Resolution
Example
The small version of the picnic table photograph below is small because
the resolution (300 ppi) "told" it to be small.
The photograph's pixels are closely spaced—300 ppi.
Similarly, the other version of the picnic table photograph is bigger
because it's resolution (72 ppi) "told" it to be big.
The same pixels are now spaced out over a larger area—72 ppi.
Resolution
Preconceptions
There are two common preconceptions about resolution.
#1 Preconception
The pixel dimensions of a file are not size
dimensions.
They're geometric dimensions.
A JPEG file from a 6 megapixel camera typically has these pixel dimensions:
3008 pixels x 2000 pixels
It looks like the file has a physical size, but it doesn't.
3008 x 2000 is just a description of how the pixels are arranged—their
geometric pattern—not their size.
The file needs a resolution to "tell" the pixels how big they should
be.
We'll get to that.
#2 Preconception
People often think that pixels have a fixed size.
Nope.
Pixels can change their size.
If we squish them into a small print, they get smaller.
If we spread them thinly on a huge print, they get bigger.
Pixels are very accommodating.
Let's look at another example.
