When I am playing a TV episode or movie and I press the OK button, the pause menu shows. At the bottom, it shows the length of the movie in time & how long the movie has been playing. What I want to do, is to increase the brightness of the time numbers. How?
Which skin are you using?
Stock standard OSMC.
The text in those areas is our “non-focus” text. You may go to the skin settings and adjust the colour there under colour/custom. But it will also alter the non-focus text everywhere in the skin thus reducing contrast between focus and non-focus text, if you make it brighter/less opaque… 
Thank you. Had a play around after taking note of what the defaults are. I left the Background Opacity & Overlay Opacity at their defaults. Under Custom, I clicked on the Non-focus text colour, agreed to the download of the Add-on and changed the Opacity to 80%. It gave me CCFFFFE3. I don’t know what that means but I am sure you will. I did take it up to 100% but found that too glaring. When I do updates, will what I changed stay changed?
Of course, these settings will be preserved 