Photos grainy in PE15 after editing in ACR on Mac OS

elissad56292093  wrote When I have taken pictures on my T5i in Raw/JPEG and open them in ACR, I can edit them fine and they look crystal clear. When I open them in photoshop elements after editing (or not) in ACR, they appear grainy at any zoom level below 25%. Can anyone help? This is driving me crazy!

Contrary to what your title seems to suggest, your problem has nothing to do with Macs nor with ACR.

What you are seeing is not grain (that only exists with silver photography) nor noise (typical of high ISO shots).

It's pixellisation resulting from the necessity to combine pixels for showing in your display. The only true display is at 100%. Note that 50% or 25% can be combined satisfactorily. Any viewing at intermediate values, especially under 25% will show a loss of precision. That's the nature of digital files and displays.