Whether you are adding titles in the lower third of a video or creating text captions to be placed on top of a coloured photograph, the text should be readable irrespective of the color of the background image.
If you have been struggling to find the perfect text colours for your video or image, try this simple rule. Set the fill colour as white and use a thin black outline and your text captions will be clear readable over any other colour and brightness.
This is exactly the reason why most meme generators on the Internet, including the one available on Google+ and Cheezburger.com, use a white font with a black outline for the text to be readable over any background.
And if you enable text captions for any YouTube video, you’ll find they also use the white colour with a black outline and a little amount of drop shadow. Thus the titles ill display well in the foreground even if there are different colours used in the video. The source is unknown.
One more thing. Prefer using Sans Serif fonts, like Arial, Calibri, Helvetica, Tahoma or Verdana, for your video and image captions as they are more readable than Serif typefaces.