Some updates taken from https://www.emacswiki.org/emacs/color-theme.el
in order to make this work with Emacs 26. EmacsWiki calls this
version 6.6.1, but doesn't package any other files from the upstream
tarball.

--- color-theme-6.6.0-orig/color-theme.el
+++ color-theme-6.6.0/color-theme.el
@@ -1077,13 +1077,11 @@
   (let ((rules '((font-lock-builtin-face font-lock-reference-face)
 		 (font-lock-doc-face font-lock-doc-string-face)
 		 (font-lock-constant-face font-lock-preprocessor-face)
-		 ;; In Emacs 21 `modeline' is just an alias for
-		 ;; `mode-line'.  I recommend the use of
-		 ;; `modeline' until further notice.
-		 (modeline mode-line)
-		 (modeline modeline-buffer-id)
-		 (modeline modeline-mousable)
-		 (modeline modeline-mousable-minor-mode)
+		 ;; D.ADAMS - Emacs 24.3 made `modeline' obsolete, so I've just commented-out these four lines.
+		 ;; (modeline mode-line)
+		 ;; (modeline modeline-buffer-id)
+		 ;; (modeline modeline-mousable)
+		 ;; (modeline modeline-mousable-minor-mode)
 		 (region primary-selection)
 		 (region zmacs-region)
 		 (font-lock-string-face dired-face-boring "^dired")
@@ -1254,7 +1252,9 @@
 	   (val (cdr (assq param params)))
 	   (frame (if color-theme-is-global nil (selected-frame))))
       (when val
-	(set-face-property face prop val frame)))))
+	(if (fboundp 'set-face-property)
+	    (set-face-property face prop val frame)
+	  (set-face-attribute face frame prop val))))))
 
 (defun color-theme-alist-reduce (old-list)
   "Reduce OLD-LIST.
@@ -1332,7 +1332,9 @@
     (dolist (var vars)
       (if (or color-theme-is-global color-theme-xemacs-p)
 	  (set (car var) (cdr var))
-	(make-variable-frame-local (car var))
+	;; DADAMS
+	;; `make-variable-frame-local' was removed from Emacs C code in Emacs 26.
+	(when (fboundp 'make-variable-frame-local) (make-variable-frame-local (car var)))
 	(modify-frame-parameters (selected-frame) (list var))))))
 
 (defun color-theme-install-faces (faces)