Today’s Question: As you know, the Crop tool in [Photoshop and] Photoshop Elements allows one to record the desired width and height in inches for an image to be printed. To the right of this is a box for “Resolution.” My question is, how does one determine what that resolution number should be?
Tim’s Quick Answer: The optimal output resolution setting will vary based on the specific output method. However, when printing an image a good starting point for a baseline resolution is 300 pixels per inch (ppi).
More Detail: If you were simply trying to crop an original image to a specific aspect ratio, but you don’t want to resize the image in the process, you should leave the Resolution field for the Crop tool blank. A blank value for Resolution will cause the crop box to fit the aspect ratio you’ve defined, but the image will only be cropped without resizing in terms of the overall dimensions. In other words, you would be trimming pixels out of the image without resizing to a specific output size.
If you are cropping an image to prepare it for printing, then you will want to specify a Resolution value for the Crop tool so the image will actually be resized to the specific intended output. The Resolution is only really a factor when preparing a photo for printing, not for preparing a photo for digital output.
So, the Resolution setting for the Crop tool can be thought of as mostly a tool to use when preparing an image for printing. In general, a resolution of 300 pixels per inch (ppi) works well for most printed output. If you’re using a photo inkjet printer, in most cases you’ll get best results with a resolution of up to 360 ppi, though the specific optimal setting will depend on the printer being used to produce the print.
In general, a resolution of at least 300 ppi will provide excellent results with just about any printer. A higher setting may result in improved print quality depending on the printer being used, although in most cases there won’t be a clear advantage to settings above about 400 ppi.