I use H264 for proxy media..You may ask why.. because i run out of space...
can i just like that color grade being in proxy media playback set to proxy only
or i should switch to orginal media???
does it makes any difference
Yes, you should switch Media Playback to Optimized/Original before color grading and have it on that setting for export to get the best quality. I'm not sure about the Quality setting in the View menu, whether it affects output quality or not.
I would recommend having "Better Quality" selected, along with "Optimized/Original" when grading. If you try to grade using a proxy version of a clip you won't be seeing the best quality image (and that may affect your choices during grading).
As a test, you can take a sample clip in the timeline that has an H.264 proxy and do some color correction on it. With the Meida Playback set to Proxy Only, you can select that clip and set I and O points for the clip only, and export it as say a ProRes 422 file. Then, switch the Media Playback setting to Optimized/Original and export the clip again to ProRes 422. Now, import both clips without making proxies, edit them into a timeline and stack one above the other. For the top clip change the blending mode to difference. You should see something besides all black (all black would mean the clips are exactly the same). I did a simple test using a "bars" generator clip that I randomly tweaked with the color settings.
P.S. - In the FCP User Guide, on page 87, it states:
Important: If you use proxy media for playback, make sure to switch back to optimized/original media before sharing your project. This ensures the highest quality in the exported file. See Intro to sharing projects in Final Cut Pro.
Yes,You are 100% Right...even i did my own test...yes we can colorgrade in proxy...but we will see the color in mainly areas like sky..some blochiness...also yes we can select our master frame switch to orginal media & start grade...Also note that i am downing 4k to 1080P...so even i do basic grade in proxy....because any apple device from 2015+ handles 1080P without any issues....so proxy is to speeds up and scrub through timeline smoothly...when comes to colour accuracy is important then scrubbing....so switching to Orginal Media is optimal...1080P proxy also usable ...anything below that is wacky...