When printing in Photoshop the default resolution is 240 dpi. I would like to increase this to 300 dpi and would be grateful for advice on how this can be done.

The other answers are correct in that there is no default print resolution, it’s whatever ppi is saved in the specific image you are printing. So if you have 10 images that were saved at 10 different ppi values, those are the 10 different ppi values that each of them will have going into the Print dialog box.

You can change this right there in the Print dialog box. If an image was saved at a ppi value other than 300 ppi, you can adjust its width and height until it’s 300 ppi, as shown in the demo below. The reason it works this way is that the effective ppi resolution is always the number of pixels along one dimension (width or height) divided by the number of inches in the print size. So if you want a 10-inch-wide print to be 300 ppi, then there is only one possible number that the image width can be: 3000 pixels (3000 pixels / 10 inches = 300 pixels per inch).

If the image you are printing doesn’t evenly divide into 300 ppi at the print size in inches that you want, then to make it 300 ppi you must resample the image (add or remove pixels until it has the width that you want in pixels). JohanElzenga already replied about how to do that in Image Size.

​@stamed 

Why do you believe that want or need 300 PPI?

300 PPI and 240 PPI both come from different specific historical backgrounds - but they are not “magic” numbers.

Print method, paper, viewing distance/conditions and image content all play their roles. Print quality is the sum of many parts!

EDIT:

The following article is well worth translating from French…

300 PPI: the cult of useless pixels

https://www.linkedin.com/pulse/300-ppp-le-culte-des-pixels-inutiles-branislav-mili%25C4%2587-1qx6f/

​@stamed wrote: “the default resolution is 240 dpi”

Dots per inch (dpi) are determined by your printer, not Photoshop. You can choose the dpi for some printers in the print settings dialog. Adorama has a good list of high dpi printers:

https://www.adorama.com/lists/high-dpi-printers

In Photoshop you can only set pixels per inch (ppi).

Jane

I’m guessing you’re opening images from Camera Raw or Lightroom Classic? That’s where the 240 number comes from. Change the default in Camera Raw/Lightroom Classic Preferences.

The default resolution is set to whatever the image is set to. So go to ‘Image Size’, uncheck ‘Resample’ and set the Resolution to 300 ppi.