diff --git a/development/FORMAT b/development/FORMAT
index 4e6dcc0f1c..2fff885219 100644
--- a/development/FORMAT
+++ b/development/FORMAT
@@ -7,6 +7,10 @@ changes happened in particular if possible. A good example would be
 
 -----------------------
 
+2021-01-19 Jürgen Spitzmüller <spitz@lyx.org>
+ 	* Format incremented to 604: Branch colors now take two values:
+ 	  \color lightmode darkmode
+
 2021-01-18 Jürgen Spitzmüller <spitz@lyx.org>
  	* Format incremented to 603: New InsetGraphics param darkModeSensitive
  	  This advises LyX to revert colors in dark mode.
diff --git a/lib/lyx2lyx/lyx_2_4.py b/lib/lyx2lyx/lyx_2_4.py
index 0fc850baef..d3177f9787 100644
--- a/lib/lyx2lyx/lyx_2_4.py
+++ b/lib/lyx2lyx/lyx_2_4.py
@@ -4086,6 +4086,26 @@ def revert_darkmode_graphics(document):
         i += 1
 
 
+def revert_branch_darkcols(document):
+    " Revert dark branch colors "
+
+    i = 0
+    while True:
+        i = find_token(document.header, "\\branch", i)
+        if i == -1:
+            break
+        j = find_token(document.header, "\\end_branch", i)
+        if j == -1:
+           document.warning("Malformed LyX document. Can't find end of branch definition!")
+           break
+        k = find_token(document.header, "\\color", i, j)
+        if k != -1:
+            m = re.search('\\\\color (\S+) (\S+)', document.header[k])
+            if m:
+                document.header[k] = "\\color " + m.group(1)
+        i += 1
+
+
 ##
 # Conversion hub
 #
@@ -4150,10 +4170,12 @@ convert = [
            [600, []],
            [601, [convert_math_refs]],
            [602, [convert_branch_colors]],
-           [603, []]
+           [603, []],
+           [604, []]
           ]
 
-revert =  [[602, [revert_darkmode_graphics]],
+revert =  [[603, [revert_branch_darkcols]],
+           [602, [revert_darkmode_graphics]],
            [601, [revert_branch_colors]],
            [600, []],
            [599, [revert_math_refs]],
diff --git a/src/BranchList.cpp b/src/BranchList.cpp
index aa8551ed5d..f21fec57a7 100644
--- a/src/BranchList.cpp
+++ b/src/BranchList.cpp
@@ -29,7 +29,8 @@ namespace lyx {
 Branch::Branch()
 	: selected_(false), filenameSuffix_(false)
 {
-	color_ = "background";
+	lmcolor_ = "background";
+	dmcolor_ = "background";
 }
 
 
@@ -74,23 +75,57 @@ void Branch::setFileNameSuffix(bool b)
 
 string const & Branch::color() const
 {
-	return color_;
+	return (theApp() && theApp()->isInDarkMode())
+			? dmcolor_ : lmcolor_;
 }
 
 
-void Branch::setColor(string const & str)
+string const & Branch::lightModeColor() const
 {
-	color_ = str;
+	return lmcolor_;
+}
+
+
+string const & Branch::darkModeColor() const
+{
+	return dmcolor_;
+}
+
+
+void Branch::setColor(string const & col)
+{
+	if (theApp() && theApp()->isInDarkMode())
+		setColors(string(), col);
+	else
+		setColors(col);
+}
+
+
+void Branch::setColors(string const & lmcol, string const & dmcol)
+{
+	if (lmcol.empty() && lmcolor_ == "background" && support::prefixIs(dmcol, "#"))
+		lmcolor_ = X11hexname(inverseRGBColor(rgbFromHexName(dmcol)));
+	else if (!lmcol.empty())
+		lmcolor_ = lmcol;
+	if (dmcol.empty() && dmcolor_ == "background" && support::prefixIs(lmcol, "#"))
+		dmcolor_ = X11hexname(inverseRGBColor(rgbFromHexName(lmcol)));
+	else if (!dmcol.empty())
+		dmcolor_ = dmcol;
 
 	// Update the Color table
-	string color = str;
-	bool darkmode = theApp() ? theApp()->isInDarkMode() : false;
-	if (color == "none")
-		color = lcolor.getX11HexName(Color_background, darkmode);
-	else if (color.size() != 7 || color[0] != '#')
-		color = lcolor.getX11HexName(lcolor.getFromLyXName(color), darkmode);
+	string lmcolor = lmcolor_;
+	string dmcolor = dmcolor_;
+	if (lmcolor == "none")
+		lmcolor = lcolor.getX11HexName(Color_background);
+	else if (lmcolor.size() != 7 || lmcolor[0] != '#')
+		lmcolor = lcolor.getX11HexName(lcolor.getFromLyXName(lmcolor));
+	if (dmcolor == "none")
+		lmcolor = lcolor.getX11HexName(Color_background, true);
+	else if (dmcolor.size() != 7 || dmcolor[0] != '#')
+		dmcolor = lcolor.getX11HexName(lcolor.getFromLyXName(dmcolor), true);
+
 	// FIXME UNICODE
-	lcolor.setColor(to_utf8(branch_), color);
+	lcolor.setColor(to_utf8(branch_), lmcolor, dmcolor);
 }
 
 
diff --git a/src/BranchList.h b/src/BranchList.h
index cdae7b6d0c..2c6d0eb578 100644
--- a/src/BranchList.h
+++ b/src/BranchList.h
@@ -62,13 +62,21 @@ public:
 	void setFileNameSuffix(bool);
 	///
 	std::string const & color() const;
+	///
+	std::string const & lightModeColor() const;
+	///
+	std::string const & darkModeColor() const;
 	/**
-	 * Set color from a hexcolor string "#rrggbb" or a lyx color name.
+	 * Set background color from a hexcolor string "#rrggbb" or a lyx color name.
 	 * Use Color:background if the string is no valid color.
 	 * This ensures compatibility with LyX 1.4.0 that had the symbolic
 	 * color "none" that was displayed as Color:background.
+	 * This sets the dark color if in dark mode, else the light color.
 	 */
-	void setColor(std::string const &);
+	void setColor(std::string const & color);
+	/// Set dark and light background colors
+	void setColors(std::string const & color,
+		      std::string const & dmcolor = std::string());
 
 private:
 	///
@@ -77,8 +85,10 @@ private:
 	bool selected_;
 	///
 	bool filenameSuffix_;
-	///
-	std::string color_;
+	/// light mode background color
+	std::string lmcolor_;
+	/// dark mode background color
+	std::string dmcolor_;
 };
 
 
diff --git a/src/BufferParams.cpp b/src/BufferParams.cpp
index 2c9821cffa..607ea2dca6 100644
--- a/src/BufferParams.cpp
+++ b/src/BufferParams.cpp
@@ -990,9 +990,13 @@ string BufferParams::readToken(Lexer & lex, string const & token,
 			}
 			if (tok == "\\color") {
 				lex.eatLine();
-				string color = lex.getString();
+				vector<string> const colors = getVectorFromString(lex.getString(), " ");
+				string const lmcolor = colors.front();
+				string dmcolor;
+				if (colors.size() > 1)
+					dmcolor = colors.back();
 				if (branch_ptr)
-					branch_ptr->setColor(color);
+					branch_ptr->setColors(lmcolor, dmcolor);
 			}
 		}
 	} else if (token == "\\index") {
@@ -1382,7 +1386,7 @@ void BufferParams::writeFile(ostream & os, Buffer const * buf) const
 		os << "\\branch " << to_utf8(br.branch())
 		   << "\n\\selected " << br.isSelected()
 		   << "\n\\filename_suffix " << br.hasFileNameSuffix()
-		   << "\n\\color " << br.color()
+		   << "\n\\color " << br.lightModeColor() << " " << br.darkModeColor()
 		   << "\n\\end_branch"
 		   << "\n";
 	}
diff --git a/src/Color.cpp b/src/Color.cpp
index 6248e67b6a..c627e5b654 100644
--- a/src/Color.cpp
+++ b/src/Color.cpp
@@ -153,6 +153,16 @@ RGBColor const RGBColorFromLaTeX(string const & color)
 }
 
 
+RGBColor const inverseRGBColor(RGBColor color)
+{
+	color.r = 255 - color.r;
+	color.g = 255 - color.g;
+	color.b = 255 - color.b;
+
+	return color;
+}
+
+
 Color::Color(ColorCode base_color) : baseColor(base_color),
 	mergeColor(Color_ignore)
 {}
diff --git a/src/Color.h b/src/Color.h
index 865f0ab8a8..d67c4989a7 100644
--- a/src/Color.h
+++ b/src/Color.h
@@ -64,6 +64,8 @@ RGBColor rgbFromHexName(std::string const & x11hexname);
 std::string const outputLaTeXColor(RGBColor const & color);
 /// Inverse of outputLaTeXColor
 RGBColor const RGBColorFromLaTeX(std::string const & color);
+/// Inverted color
+RGBColor const inverseRGBColor(RGBColor color);
 
 } // namespace lyx
 
diff --git a/src/version.h b/src/version.h
index d2ad51d619..1b15e8d6ab 100644
--- a/src/version.h
+++ b/src/version.h
@@ -32,8 +32,8 @@ extern char const * const lyx_version_info;
 
 // Do not remove the comment below, so we get merge conflict in
 // independent branches. Instead add your own.
-#define LYX_FORMAT_LYX 603 // spitz: InsetGraphicsParam darkModeSensitive
-#define LYX_FORMAT_TEX2LYX 603
+#define LYX_FORMAT_LYX 604 // spitz: separate dark branch color
+#define LYX_FORMAT_TEX2LYX 604
 
 #if LYX_FORMAT_TEX2LYX != LYX_FORMAT_LYX
 #ifndef _MSC_VER