I'm running GNU Emacs 24.5.4 on Mac OS X 10.10.5 in Terminal.app.
In this (stock) setup, Emacs has a transparent background. With a transparent background, the colors that Emacs uses to display text are auto-adjusted based on the color underneath Emacs. In my case, "underneath Emacs" is a Terminal.app window with an opaque black background.
(In the title I refer to the "effective" theme. I'm using that to mean to the colors that Emacs actually uses to render text - as opposed to the "specified" theme, which is different in this case.)
Here is what the default theme looks like when no background color is specified in Emacs, and Emacs is running in a Terminal.app window with an opaque black background:
And here is the same setup - except with a black background specified in Emacs:
While beauty is certainly in the eye of the beholder, I've gotten used to the colors in the top image.
So I'd like to duplicate those colors in GUI Emacs. But since GUI Emacs isn't a transparent window always running on top of something with a black background and hence having colors auto-adjusted, setting its background to black results in the coloring shown in the bottom screenshot.
How do I duplicate the 'effective' colors used in the top screenshot so that they are used in GUI Emacs as well?
P.S. Here's a video demonstrating the text color adjustments happening in real-time vs. changes to the background color of Terminal.app: vimeo.com/139967912. (I had to use an external camera since QuickTime Player's screen recording didn't work for this purpose.)