diff --git a/colors.lua b/colors.lua
index 0faeb43..9405bc3 100644
--- a/colors.lua
+++ b/colors.lua
@@ -7,6 +7,9 @@
 	LICENSE is BEER-WARE.
 ]]
 
+local GAMMA = 2.2
+local GAMMA_INV = 1/GAMMA
+
 local colors = {}
 
 --------------------------------------------------------------------------------
@@ -83,13 +86,14 @@ end
 -- Interpolation
 
 colors.interpolate_rgb = function (c1, c2, t)
-	assert(type(c1) == 'table' and type(c1[1]) == 'number' and type(c1[2]) == 'number' and type(c1[3]) == 'number' and (type(c1[4]) == 'number' or c1[4] == nil))
-	assert(type(c2) == 'table' and type(c2[1]) == 'number' and type(c2[2]) == 'number' and type(c2[3]) == 'number' and (type(c2[4]) == 'number' or c2[4] == nil))
-	assert(type(t) == 'number')
-	--	
-	local alpha = nil
-	if c1[4] or c2[4] then  alpha = (c1[4] or 255) + ((c2[4] or 255)-(c1[4] or 255))*t  end
-	return { c1[1]+(c2[1]-c1[1])*t, c1[2]+(c2[2]-c1[2])*t, c1[3]+(c2[3]-c1[3])*t, alpha }
+	return { c1[1]+(c2[1]-c1[1])*t, c1[2]+(c2[2]-c1[2])*t, c1[3]+(c2[3]-c1[3])*t }
+end
+
+colors.interpolate_rgb_gamma_adjusted = function (c1, c2, t)
+    local c1_r, c1_g, c1_b = c1[1]^GAMMA, c1[2]^GAMMA, c1[3]^GAMMA
+    local c2_r, c2_g, c2_b = c2[1]^GAMMA, c2[2]^GAMMA, c2[3]^GAMMA
+    local c3_r, c3_g, c3_b = c1_r+(c2_r-c1_r)*t, c1_g+(c2_g-c1_g)*t, c1_b+(c2_b-c1_b)*t
+    return c3_r^GAMMA_INV, c3_g^GAMMA_INV, c3_b^GAMMA_INV
 end
 
 local function angle_delta (a1, a2)
@@ -151,3 +155,4 @@ end
 --------------------------------------------------------------------------------
 
 return colors
+