scan size vs image size in PSE 15

I totally agree with hatstead.

janabailey66  wrote When I scan in some of my art using my HP scanner, the settings are set at 12 x 12 and 300dpi.  After the scan is complete and I open the jpeg on my MacBook Pro in preview it states that it is 12 x 12 inches, 300 dpi and 2.7 MB.  All like I'd like it.  But when I open it to edit it in PSE 15 it always opens at 50 x 50 inches, 72 dpi and 37 MB.  Why in the world??

Another way to see the 300 vs 72 ppi resolution choice: resolution means how many individual pixels are displayed/printed/scanned on a given input/output: paper, slide, for a given size in in/cm.

A digital image is made of pixels, the size in in/cm/mm is not relevant. The same dimensions in pixels can be printed, displayed or scanned at any in/cm dimension (the pixels will be big or small). The dimensions in inches you are seeing are just indications of the size your image will have when YOU chose a given resolution in pixels per inches (ppi).

To play with this, use the menu Image/resize/image size, without checking the 'resample image' (which changes the number or pixels).

Change the the ppi to 72, 96, 240,300 and the resulting image size in in/cm will be calculated so that you can appraise the quality of the print. 72 is good for displaying on a display or on the Web, 240 - 300 for printing or scanning prints, 2400 would be ideal for fine 135 mmm slides...

The 'resample' function is an interpolation process to reduce or increase the number of pixels. That does not give more details, but that may optimize not only the size in pixels, but also help to avoid the 'scales' effect for straight lines.

janabailey66  wrote I'm a newbie, kind of, and I can't figure out why this is happening.  When I scan in some of my art using my HP scanner, the settings are set at 12 x 12 and 300dpi.  After the scan is complete and I open the jpeg on my MacBook Pro in preview it states that it is 12 x 12 inches, 300 dpi and 2.7 MB.  All like I'd like it.  But when I open it to edit it in PSE 15 it always opens at 50 x 50 inches, 72 dpi and 37 MB.  Why in the world??

You are referring to two different metrics.

DPI=dots per inch. This is determined by the printer/scanner.

PPI=pixels per inch, which is the resolution of the file. When you go to Image>resize>image size, this is where you read the resolution value in px/in. In this dialog you can resize by resampling.

If your goal is to use the artwork file(s) for web work, 72 px/in is ok.

For printing, it is recommended to have the resolution in the 240-300px/in range, although I have printed successfully below this value, esp. with larger prints where the observer's eye is at a distance from the print.

I don't have a clue as to your MacBook Pro, as I don't have one.