emacs-27 6916e79: Improve documentation of 'ps-print-color-p'

[Eli Zaretskii]

branch: emacs-27
commit 6916e7954ab5de5e2dc7b25f165a63396d0e70a0
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Improve documentation of 'ps-print-color-p'
    
    * doc/emacs/misc.texi (PostScript Variables): Improve and clarify
    the description of 'ps-print-color-p'.  (Bug#44962)
---
 doc/emacs/misc.texi | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 2f02c70..5f70036 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -2252,13 +2252,18 @@ off.
 @vindex ps-print-color-p
   If your printer doesn't support colors, you should turn off color
 processing by setting @code{ps-print-color-p} to @code{nil}.  By
-default, if the display supports colors, Emacs produces hardcopy output
-with color information; on black-and-white printers, colors are emulated
-with shades of gray.  This might produce illegible output, even if your
-screen colors only use shades of gray.
-
-  Alternatively, you can set @code{ps-print-color-p} to @code{black-white} to
-print colors on black/white printers.
+default, if the display supports colors, Emacs produces hardcopy
+output with color information; on black-and-white printers, colors are
+emulated with shades of gray.  This might produce barely-readable or
+even illegible output, even if your screen colors only use shades of
+gray.
+
+@vindex ps-black-white-faces
+  Alternatively, you can set @code{ps-print-color-p} to @code{black-white}
+to have colors display better on black/white printers.  This works by
+using information in @code{ps-black-white-faces} to express colors by
+customizable list of shades of gray, augmented by bold and italic
+face attributes.
 
 @vindex ps-use-face-background
   By default, PostScript printing ignores the background colors of the