Update docs/tutorial/kymographs.rst

I like that suggestion. Then the contribution of background to the signal is more visible. The user can always subtract it later.

Co-authored-by: Joep Vanlier <[email protected]>

docs/tutorial/kymographs.rst

@@ -175,7 +175,8 @@ Since every pixel has an average background signal of `background_mean`, we need
     time = np.arange(len(summed_photon_counts)) * kymo.line_time_seconds
 
     plt.figure()
-    plt.plot(time, summed_photon_counts - summed_background)
+    plt.plot(time, summed_photon_counts)
+    plt.axhline(summed_background, color='k', linestyle='--')
     plt.xlabel("time (s)")
     plt.ylabel("Signal Intensity")
     plt.title("Photon counts along binding event minus background")