diff --git a/src/openrct2/drawing/string.c b/src/openrct2/drawing/string.c
index cc517ea247..fc45f42bb3 100644
--- a/src/openrct2/drawing/string.c
+++ b/src/openrct2/drawing/string.c
@@ -717,48 +717,6 @@ static void ttf_draw_string_raw_sprite(rct_drawpixelinfo *dpi, const utf8 *text,
 
 #ifndef NO_TTF
 
-static uint8 colormap[256][256] = {0};
-
-uint8 findClosestIndex(uint8 red, uint8 green, uint8 blue)
-{
-    sint16 closest = -1;
-    sint32 closestDistance = INT32_MAX;
-
-    for (int i = 0; i < 256; i++)
-    {
-        const int distance =
-            pow(gPalette[i].red - red, 2) + pow(gPalette[i].green - green, 2) + pow(gPalette[i].blue - blue, 2);
-
-        if (distance < closestDistance)
-        {
-            closest = i;
-            closestDistance = distance;
-        }
-    }
-
-    return closest;
-}
-
-uint8 blend(const uint8 base, const uint8 layer)
-{
-    const uint8 cMin = min(base, layer);
-    const uint8 cMax = max(base, layer);
-
-    if (colormap[cMin][cMax] != 0)
-    {
-        return colormap[cMin][cMax];
-    }
-
-    log_info("Blending colours %d and %d", cMin, cMax);
-
-    uint8 red = (gPalette[cMin].red + gPalette[cMax].red) / 2;
-    uint8 green = (gPalette[cMin].green + gPalette[cMax].green) / 2;
-    uint8 blue = (gPalette[cMin].blue + gPalette[cMax].blue) / 2;
-
-    colormap[cMin][cMax] = findClosestIndex(red, green, blue);
-    return colormap[cMin][cMax];
-}
-
 static void ttf_draw_string_raw_ttf(rct_drawpixelinfo *dpi, const utf8 *text, text_draw_info *info)
 {
     if (!ttf_initialise())
diff --git a/src/openrct2/interface/colour.c b/src/openrct2/interface/colour.c
index 86da749f21..ae71a59c3b 100644
--- a/src/openrct2/interface/colour.c
+++ b/src/openrct2/interface/colour.c
@@ -62,3 +62,47 @@ void colours_init_maps()
         ColourMapA[i].colour_11 = g1Element->offset[INDEX_COLOUR_11];
     }
 }
+
+#ifndef NO_TTF
+static uint8 BlendColourMap[PALETTE_COUNT][PALETTE_COUNT] = {0};
+
+static uint8 findClosestIndex(uint8 red, uint8 green, uint8 blue)
+{
+    sint16 closest = -1;
+    sint32 closestDistance = INT32_MAX;
+
+    for (int i = 0; i < PALETTE_COUNT; i++)
+    {
+        const int distance =
+            pow(gPalette[i].red - red, 2) + pow(gPalette[i].green - green, 2) + pow(gPalette[i].blue - blue, 2);
+
+        if (distance < closestDistance)
+        {
+            closest = i;
+            closestDistance = distance;
+        }
+    }
+
+    return closest;
+}
+
+uint8 blend(const uint8 base, const uint8 layer)
+{
+    const uint8 cMin = min(base, layer);
+    const uint8 cMax = max(base, layer);
+
+    if (BlendColourMap[cMin][cMax] != 0)
+    {
+        return BlendColourMap[cMin][cMax];
+    }
+
+    log_info("Blending colours %d and %d", cMin, cMax);
+
+    uint8 red = (gPalette[cMin].red + gPalette[cMax].red) / 2;
+    uint8 green = (gPalette[cMin].green + gPalette[cMax].green) / 2;
+    uint8 blue = (gPalette[cMin].blue + gPalette[cMax].blue) / 2;
+
+    BlendColourMap[cMin][cMax] = findClosestIndex(red, green, blue);
+    return BlendColourMap[cMin][cMax];
+}
+#endif
diff --git a/src/openrct2/interface/colour.h b/src/openrct2/interface/colour.h
index 735982e830..e2da007032 100644
--- a/src/openrct2/interface/colour.h
+++ b/src/openrct2/interface/colour.h
@@ -111,6 +111,8 @@ enum
     PALETTE_INDEX_209 = 209,    // Bright Pink (light)
     PALETTE_INDEX_222 = 222,    //
     PALETTE_INDEX_245 = 245,    //
+
+    PALETTE_COUNT = 256,
 };
 
 #define TEXT_COLOUR_254         (254)
@@ -148,6 +150,10 @@ extern rct_colour_map ColourMapA[COLOUR_COUNT];
 
 void colours_init_maps();
 
+#ifndef NO_TTF
+uint8 blend(const uint8 base, const uint8 layer);
+#endif
+
 #ifdef __cplusplus
 }
 #endif