--- leptonlib-1.52/src/colormap.c	2007-11-25 01:15:24.000000000 +0300
+++ leptonlib-1.52.my/src/colormap.c	2007-12-19 19:13:17.000000000 +0300
@@ -437,7 +437,7 @@
     *prval = *pgval = *pbval = 0;
     if (!cmap)
         return ERROR_INT("cmap not defined", procName, 1);
-    if (index >= cmap->n)
+    if (index < 0 && index >= cmap->n)
         return ERROR_INT("index out of bounds", procName, 1);
 
     cta = (RGBA_QUAD *)cmap->array;