To utilize this new feature, start in Photoshop’s Preferences menu, and look for the menu item called Technology Previews. It’s sort of the “beta testing” area for new tools. The checkbox next to Enable Preserve Details 2.0 Upscale should be checked by default, but if it’s not, make sure to check it and then click okay to close the dialogue box.
With the image open that you’d like to upscale, click Image Size on Photoshop’s Image menu to open the Image Size dialogue box. Here, you’ll see the current pixel dimensions of the file (the truest way to measure the actual size of an image file, irrespective of dots per inch shown here next to resolution) in width and height, measured in pixels. Enter the new width or height, and with the lock engaged to constrain the proportions, the other entry will change accordingly. Before clicking okay, however, make sure Resample is checked and then adjust the resampling method by clicking the word Automatic to open the dropdown and choosing Preserve Details 2.0. Normally the Automatic setting will choose the most appropriate resampling algorithm for the situation, but because Preserve Details 2.0 is still in testing, it must be selected manually.
When you enter new dimensions, the preview window will update to show you what the result will look like. You can grab the corner of this dialogue box and drag it to resize the preview and make it much larger for a better view of the results.
With the JPEG image shown here, I doubled the image size and it’s evident from the upscaled detail image just how effective Preserve Details 2.0 is at sharpening the right details without amplifying noise or creating artifacts. Adobe touts this technique as being able to effectively enlarge an image as much as 400%. As important as sensor resolution is in determining the overall quality and size of a photograph, Preserve Details 2.0 is the kind of technology that makes camera resolution matter a lot less.