diff --git a/Data/Color.hs b/Data/Color.hs
--- a/Data/Color.hs
+++ b/Data/Color.hs
@@ -70,7 +70,7 @@
     fromString x = error $ "Invalid color representation: " ++ x
 
 -- | Blend two colors.
-blend :: Num a => Float -> RGBA -> RGBA -> RGBA
+blend :: Float -> RGBA -> RGBA -> RGBA
 blend t (RGBA r0 g0 b0 a0) (RGBA r1 g1 b1 a1) = RGBA
     (r0 * (1 - t) + r1 * t)
     (g0 * (1 - t) + g1 * t)
diff --git a/colors.cabal b/colors.cabal
--- a/colors.cabal
+++ b/colors.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                colors
-version:             0.2
+version:             0.2.0.1
 synopsis:            A type for colors
 -- description:         
 homepage:            https://github.com/fumieval/colors