diff --git a/src/Emphasise.lua b/src/Emphasise.lua
index f56f295..694db16 100644
--- a/src/Emphasise.lua
+++ b/src/Emphasise.lua
@@ -2,6 +2,7 @@ local GetLuminance = require(script.Parent.GetLuminance)
 local Lighten = require(script.Parent.Lighten)
 local Darken = require(script.Parent.Darken)
 
-return function(colour: Color3, coefficient: number): Color3
-    return GetLuminance(colour) > .5 and Darken(colour, coefficient) or Lighten(colour, coefficient)
+return function(colour: Color3, coefficient: number, threshold: number?): Color3
+    threshold = type(threshold) == "number" and threshold or .5
+    return GetLuminance(colour) > threshold and Darken(colour, coefficient) or Lighten(colour, coefficient)
 end
diff --git a/src/Emphasise.spec.lua b/src/Emphasise.spec.lua
index 74ea284..badc2bd 100644
--- a/src/Emphasise.spec.lua
+++ b/src/Emphasise.spec.lua
@@ -12,4 +12,14 @@ return function()
         local colour = Color3.fromRGB(250, 240, 230)
         expect(Emphasise(colour, .3)).to.equal(Darken(colour, .3))
     end)
+
+    it("lightens a light colour with a high threshold", function()
+        local colour = Color3.fromRGB(230, 220, 210)
+        expect(Emphasise(colour, .1, .9)).to.equal(Lighten(colour, .1))
+    end)
+
+    it("darkens a dark colour with a low threshold", function()
+        local colour = Color3.new(.2, .2, .2)
+        expect(Emphasise(colour, .1, .01)).to.equal(Darken(colour, .1))
+    end)
 end