Community Beginner , Sep 06, 2023. Unfortunately on a mac ayt leadst there is NO default RGB to CMYK conversion action. Its just not part of PS. I can't undertsnad why people sare saying, "yeah for batch RGB to CMYK coversion, go in PS and in the File>Automate>Batch.
For this issue, Image Editors like Photoshop use CMYK **MODE**.In this mode , if you select the RGB color, the editor convert it to color that you see after printing and shows that to screen.this conversion is absolutely depend on color Profiles ( here ICC )Aditional tip. You can convert an image directly from RGB to grayscale, but you also can try using a specific channel. Imagine this photo: A blue sky as a background with a tree with red leaves as your main subject. .