diff --git a/code/modules/lighting/light_source.dm b/code/modules/lighting/light_source.dm
index ae9df7bb702..808f4d1dc3a 100644
--- a/code/modules/lighting/light_source.dm
+++ b/code/modules/lighting/light_source.dm
@@ -11,9 +11,9 @@
 	var/lum_g
 	var/lum_b
 
-	var/tmp/old_lum_r
-	var/tmp/old_lum_g
-	var/tmp/old_lum_b
+	var/tmp/applied_lum_r
+	var/tmp/applied_lum_g
+	var/tmp/applied_lum_b
 
 	var/list/effect_str
 	var/list/effect_turf
@@ -107,11 +107,6 @@
 	if(light_range && light_power && !applied)
 		. = 1
 
-	if(. || source_atom.light_color != light_color)//Save the old lumcounts if we need to update, if the colour changed DO IT BEFORE we parse the colour and LOSE the old lumcounts!
-		old_lum_r = lum_r
-		old_lum_g = lum_g
-		old_lum_b = lum_b
-
 	if(source_atom.light_color != light_color)
 		light_color = source_atom.light_color
 		parse_light_color()
@@ -149,6 +144,12 @@
 
 /datum/light_source/proc/apply_lum()
 	applied = 1
+
+	// Cache the applied lum counts.
+	applied_lum_r = lum_r
+	applied_lum_g = lum_g
+	applied_lum_b = lum_b
+
 	if(istype(source_turf))
 		FOR_DVIEW(var/turf/T, light_range, source_turf, INVISIBILITY_LIGHTING)
 			if(T.lighting_overlay)
@@ -188,7 +189,7 @@
 
 		if(T.lighting_overlay)
 			var/str = effect_str[i]
-			T.lighting_overlay.update_lumcount(-str * old_lum_r, -str * old_lum_g, -str * old_lum_b)
+			T.lighting_overlay.update_lumcount(-str * applied_lum_r, -str * applied_lum_g, -str * applied_lum_b)
 
 		i++