diff --git a/matlab/reports/@graph/writeGraphFile.m b/matlab/reports/@graph/writeGraphFile.m
index 40463c4ac2ddff88de9891b3235dba35371bdef5..e0d415a9dc7f017a600d025ff7384970fd48f1e6 100644
--- a/matlab/reports/@graph/writeGraphFile.m
+++ b/matlab/reports/@graph/writeGraphFile.m
@@ -142,8 +142,9 @@ if ~isempty(o.shade)
                         date2string(o.shade(1)) ' or ' date2string(o.shade(end)) ' is not in the date ' ...
                         'range of data selected.']);
     fprintf(fid, ['%%shading\n\\addplot[area legend,solid,fill=%s,' ...
-                  'opacity=.2,draw=black,forget plot]\ntable[row sep=crcr]{\nx y\\\\\n%d %d\\\\\n%d %d\\\\\n%d %d\\\\\n%d %d\\\\\n};\n'], ...
-            o.shadeColor, x1, ymin, x1, ymax, x2, ymax, x2, ymin);
+                  'opacity=%f,draw=black,forget plot]\ntable[row sep=crcr]{\nx ' ...
+                  'y\\\\\n%d %d\\\\\n%d %d\\\\\n%d %d\\\\\n%d %d\\\\\n};\n'], ...
+            o.shadeColor, o.shadeOpacity, x1, ymin, x1, ymax, x2, ymax, x2, ymin);
 end
 
 for i=1:ne