diff --git a/plots/README.md b/plots/README.md
index b805512..388bb8d 100644
--- a/plots/README.md
+++ b/plots/README.md
@@ -3,3 +3,7 @@
 ## discrete_colour_ramp.py
 
 ![discrete colour ramp](png/discrete-colour-ramp.png)
+
+## discrete_colour_ramp_edges.py
+
+![discrete colour ramp edges](png/discrete-colour-ramp-edges.png)
diff --git a/plots/discrete_colour_ramp.py b/plots/discrete_colour_ramp.py
index 2e5ab88..1fc7714 100644
--- a/plots/discrete_colour_ramp.py
+++ b/plots/discrete_colour_ramp.py
@@ -15,7 +15,7 @@ c_min = -8
 c_step = 2
 
 # Create colour map
-cmap = plt.cm.get_cmap('Blues', (c_max - c_min + c_step) / c_step)
+cmap = plt.cm.get_cmap('YlOrRd', (c_max - c_min + c_step) / c_step)
 
 fig, ax = plt.subplots(1, 1, figsize=(6, 4))
 
diff --git a/plots/discrete_colour_ramp_edges.py b/plots/discrete_colour_ramp_edges.py
new file mode 100644
index 0000000..0c7ffef
--- /dev/null
+++ b/plots/discrete_colour_ramp_edges.py
@@ -0,0 +1,39 @@
+import os
+import numpy as np
+import matplotlib.pyplot as plt
+
+# Generate dummy data
+delta = 0.01
+x = np.arange(-3.0, 3.0, delta)
+y = np.arange(-3.0, 3.0, delta)
+X, Y = np.meshgrid(x, y)
+Z = X * Y
+
+# Set range and steps for colour bar
+c_max = 5
+c_min = -5
+c_step = 1
+
+# Create colour map
+cmap = plt.cm.get_cmap('YlOrRd', (c_max - c_min) / c_step)
+
+fig, ax = plt.subplots(1, 1, figsize=(6, 4))
+
+# Plot image
+im = ax.imshow(Z,
+               cmap=cmap,
+               interpolation='bilinear',
+               vmax=c_max,
+               vmin=c_min)
+
+# Add colour bar
+plt.colorbar(im, ticks=np.arange(c_min, c_max + 1, c_step))
+
+# Hide spines and ticks
+ax.set_axis_off()
+
+# Export figure
+png_name = os.path.join(
+    'png',
+    os.path.basename(__file__).replace('.py', '.png').replace('_', '-'))
+plt.savefig(png_name, bbox_inches='tight', dpi=100)
diff --git a/plots/png/discrete-colour-ramp-edges.png b/plots/png/discrete-colour-ramp-edges.png
new file mode 100644
index 0000000..81b210a
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diff --git a/plots/png/discrete-colour-ramp.png b/plots/png/discrete-colour-ramp.png
index 726fdd3..341efb3 100644
Binary files a/plots/png/discrete-colour-ramp.png and b/plots/png/discrete-colour-ramp.png differ