Cropping to the exact size and resolution seems like it should be easy, but it’s not always obvious. Sometimes when you crop the image to the size you want, the resolution is wrong, so you change the resolution. Now it’s too big or too small, so you bust out the calculator to figure it all out, and then off you go to print (or whatever the purpose is). It’s actually easy to do this using the Crop tool (C). The trick is to choose W x H x Resolution from the drop-down menu near the far left of the Options Bar when the Crop tool is selected. Now type in the width and height that you desire for your image (don’t forget to add a unit of measurement to your sizes, such as “px” for pixels, “in” for inches, etc.). Finally, in the third field in the Options Bar, add your desired resolution. A lot of people mess it up on this step. If you don’t know the resolution, here’s a rough rule of thumb: For multimedia, it’s 72 ppi, for print it’s 300 ppi, and for Epson printers it’s 360 ppi. Now crop your image and it’ll be the exact size and resolution you need.
This tip previously appeared in Colin Smith’s Photoshop Tips column, in the April, 2019 issue of Photoshop User magazine.