diff --git a/examples/automatic.py b/examples/automatic.py
index 6a70928..5f48904 100755
--- a/examples/automatic.py
+++ b/examples/automatic.py
@@ -20,6 +20,7 @@
 parser.add_argument('--nobutton', action='store_true', default=False, help='Disable button input')
 parser.add_argument('--noled', action='store_true', default=False, help='Disable LED control')
 parser.add_argument('--brightness', type=float, default=255.0, help='LED brightness, from 0 to 255')
+parser.add_argument('--extended-colours', action='store_true', default=False, help='Extend LED colours for outside of normal low to high range')
 
 args = parser.parse_args()
 
@@ -34,13 +35,13 @@ def clean_exit(signum, frame):
 def update_led_temperature(temp):
     led_busy.acquire()
     temp = float(temp)
-    if temp < args.low_temp:
+    if temp < args.low_temp and args.extended_colours:
         # Between minimum temp and low temp, set LED to blue through to green
         temp -= min_temp
         temp /= float(args.low_temp - min_temp)
         temp  = max(0, temp)
         hue   = (120.0 / 360.0) + ((1.0 - temp) * 120.0 / 360.0)
-    elif temp > args.high_temp:
+    elif temp > args.high_temp and args.extended_colours:
         # Between high temp and maximum temp, set LED to red through to magenta
         temp -= args.high_temp
         temp /= float(max_temp - args.high_temp)
@@ -50,6 +51,7 @@ def update_led_temperature(temp):
         # In the normal low temp to high temp range, set LED to green through to red
         temp -= args.low_temp
         temp /= float(args.high_temp - args.low_temp)
+        temp = max(0, min(1, temp))
         hue   = (1.0 - temp) * 120.0 / 360.0
 
     r, g, b = [int(c * 255.0) for c in colorsys.hsv_to_rgb(hue, 1.0, args.brightness / 255.0)]
diff --git a/examples/install-service.sh b/examples/install-service.sh
index 75879ff..7da0f41 100755
--- a/examples/install-service.sh
+++ b/examples/install-service.sh
@@ -10,6 +10,7 @@ POSITIONAL_ARGS=()
 NOLED="no"
 NOBUTTON="no"
 BRIGHTNESS=255
+EXTCOLOURS="no"
 PYTHON="python3"
 PIP="pip3"
 PSUTIL_MIN_VERSION="5.6.7"
@@ -19,7 +20,7 @@ OFF_THRESHOLD_SET=false
 
 SERVICE_PATH=/etc/systemd/system/pimoroni-fanshim.service
 
-USAGE="sudo ./install-service.sh --off-threshold <n> --on-threshold <n> --delay <n> --brightness <n> --low-temp <n> --high-temp <n> --venv <python_virtual_environment> (--preempt) (--noled) (--nobutton)"
+USAGE="sudo ./install-service.sh --off-threshold <n> --on-threshold <n> --delay <n> --brightness <n> --low-temp <n> --high-temp <n> --venv <python_virtual_environment> (--preempt) (--noled) (--nobutton) (--extended-colours)"
 
 # Convert Python path to absolute for systemd
 PYTHON=`type -P $PYTHON`
@@ -93,6 +94,15 @@ while [[ $# -gt 0 ]]; do
 		shift
 		shift
 		;;
+	-x|--extended-colours)
+		if [ "$2" == "yes" ] || [ "$2" == "no" ]; then
+			EXTCOLOURS="$2"
+			shift
+		else
+			EXTCOLOURS="yes"
+		fi
+		shift
+		;;
 	*)
 		if [[ $1 == -* ]]; then
 			printf "Unrecognised option: $1\n";
@@ -141,6 +151,10 @@ if [ "$NOBUTTON" == "yes" ]; then
 	EXTRA_ARGS+=' --nobutton'
 fi
 
+if [ "$EXTCOLOURS" == "yes" ]; then
+	EXTRA_ARGS+=' --extended-colours'
+fi
+
 if ! [ "$1" == "" ]; then
 	if [ $ON_THRESHOLD_SET ]; then
 		printf "Refusing to overwrite explicitly set On Threshold ($ON_THRESHOLD) with positional argument!\n"
@@ -169,15 +183,16 @@ fi
 
 cat << EOF
 Setting up with:
-Off Threshold:  $OFF_THRESHOLD C
-On Threshold:   $ON_THRESHOLD C
-Low Temp:       $LOW_TEMP C
-High Temp:      $HIGH_TEMP C
-Delay:          $DELAY seconds
-Preempt:        $PREEMPT
-Disable LED:    $NOLED
-Disable Button: $NOBUTTON
-Brightness:     $BRIGHTNESS
+Off Threshold:    $OFF_THRESHOLD C
+On Threshold:     $ON_THRESHOLD C
+Low Temp:         $LOW_TEMP C
+High Temp:        $HIGH_TEMP C
+Delay:            $DELAY seconds
+Preempt:          $PREEMPT
+Disable LED:      $NOLED
+Disable Button:   $NOBUTTON
+Brightness:       $BRIGHTNESS
+Extended Colours: $EXTCOLOURS
 
 To change these options, run:
 $USAGE