I have a clip loaded into the timeline with the timeline indicator at a particular spot that displays a single frame in the viewer. When I press play ('L', Spacebar, or button) the image appears lighter. When I stop the video, the image goes back to the darker image.
Why does this happen?
Can I change something so it will be consistent?
Which image will export (the lighter or darker one)?
Am I color correcting the correct image?
Three issues. Do you have on screen indicators like luma safe tick and title safe? I have only seen that happen when I had a whole lot of extra onscreen displays.
Secondly the play image is what will be exported.
Finally the FCP viewers and canvas are not accurate for color grading. An external feed via a card AJA/ Matrox/ Decklink etc to a calibrated monitor not a computer screen is the accurate way to grade and judge your footage.