What Does a Photo's Pixels Per Inch Mean? (MacMost 2697)

Sometimes when you provide a photo to be printed or used in a publication, you will be asked about pixels per inch, or PPI. But PPI isn't really important. Only the number of pixels in the image matters, PPI is just a setting in the file.

Comments: 2 Responses to “What Does a Photo's Pixels Per Inch Mean? (MacMost 2697)”

    Jim S.
    2 years ago

    Why is the vertical dimension ignored? Seems like a 100ppi image (width) with a one inch vertrical (length) would contain less pixels than a 100ppi image width that is 10 inches vertically. Doesn't pixels per square inch matter?

    2 years ago

    Jim: PPI is both horizontal and vertical. I use horizontal in my examples to simplify things. But if you are using 100 PPI then that is 100 PPI horizontally and 100 PPI vertically. I've never seen an image format that does anything else. That would mean rectangular pixels instead of square ones.

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