diff --git a/ESP32-RGB64x32MatrixPanel-I2S-DMA.cpp b/ESP32-RGB64x32MatrixPanel-I2S-DMA.cpp
index e632cf6..dedea53 100644
--- a/ESP32-RGB64x32MatrixPanel-I2S-DMA.cpp
+++ b/ESP32-RGB64x32MatrixPanel-I2S-DMA.cpp
@@ -430,6 +430,8 @@ void RGB64x32MatrixPanel_I2S_DMA::configureDMA(int r1_pin, int  g1_pin, int  b1_
  *
  *  Critical dependency: That 'updateMatrixDMABuffer(uint8_t red, uint8_t green, uint8_t blue)' has been run at least once over the
  *                       entire frameBuffer to ensure all the non R,G,B bitmasks are in place (i.e. like OE, Address Lines etc.)
+ *
+ *  Note: If you change the brightness with setBrightness() you MUST then clearScreen() and repaint / flush the entire framebuffer.
  */
 #define GO_FOR_SPEED 1