How to Properly Grayscale an Image in Photoshop

Many artistic effects can be achieved with black and white photography. It allows the viewer to focus on the lighting, texture, and composition that you work so hard to perfect. Here is a short video I made on how to properly grayscale an image in Photoshop. Changing the Image Mode is no longer acceptable!
Greetings from Serbia
I have only one conclusion:
never more Image mode for old photos, thank you very much!
Thank you for reading!