Digital Images, Print Size, and DPI

One problem self-publishers have with images is getting the printer’s required dots per inch while maintaining the desired image size. It doesn’t take much doodling with an image editor such as GIMP, to discover that as one increases the photo size (either in pixels or inches) the image quality decreases. The choice seems to be clear but tiny images, or large and fuzzy images.

I was equally frustrated with this problem and did some searching around on the internet. I finally found the solution at the CreateSpace forums. (Thank you Seal, wherever you are).

Here’s how to do it in the GIMP.

  1. Open image in GIMP
  2. Image > Scale image > change the X and Y resolution to desired DPI, usually 300  (make sure these are locked)
  3. File > Export image under a new file name (never overwrite your original)
  4. Now change the image size to desired width and height.
  5. File > overwrite (you may save to a new file name if you wish)

Your new image should be the size you want for your book, and at the printer’s required DPI.

I should mention another term you’ll see, PPI. PPI (pixels per inch) and DPI (dots per inch), are often used interchangeably, but technically they are not the same thing. DPI is a term that describes the abilities of a printer. PPI describes the size of a file on a computer screen. If you have question, clarify it with your chosen publisher.