diff --git a/data/minimal.frag b/data/minimal.frag
--- a/data/minimal.frag
+++ b/data/minimal.frag
@@ -12,7 +12,7 @@
   float t = texture2D(tt, gl_TexCoord[0].st).x;
   vec4 c = vec4(interior, 1.0);
   if (i > 0.0) {
-    float k = clamp(0.5 + 0.5 * log2(0.5 * d), 0.0, 1.0);
+    float k = tanh(clamp(d, 0.0, 4.0));
     c.rgb = mix(border, exterior, k);
   }
   gl_FragColor = c;
diff --git a/gruff.cabal b/gruff.cabal
--- a/gruff.cabal
+++ b/gruff.cabal
@@ -1,5 +1,5 @@
 Name:                gruff
-Version:             0.3.3
+Version:             0.3.4
 Synopsis:            fractal explorer GUI using the ruff library
 Description:
     Mandelbrot Set fractal explorer using the ruff library.
@@ -13,6 +13,8 @@
     @cabal install gruff -fmpfr@.
     Note that the default setting for this flag has changed since gruff-0.2.
     .
+    gruff-0.3.4 updates dependencies for ghc-7.8.  Colouring is improved.
+    .
     gruff-0.3.3 relaxes dependencies for ghc-7.6.
     .
     gruff-0.3.1 is a bugfix release, fixing a performance problem wherein
@@ -111,16 +113,16 @@
                       Tile
                       Utils
                       View
-  Build-depends:      gruff == 0.3.3,
+  Build-depends:      gruff == 0.3.4,
                       base >= 4 && < 6,
                       containers >= 0 && < 1,
                       directory >= 1 && < 2,
                       filepath >= 1 && < 2,
-                      FTGL == 1.333,
+                      FTGL == 2.0,
                       gtk >= 0.11 && < 0.13,
                       gtkglext >= 0.11 && < 0.13,
                       old-locale >= 1 && < 2,
-                      OpenGL >= 2.4 && < 3,
+                      OpenGL >= 2.9 && < 2.10,
                       OpenGLRaw >= 1.1 && < 2,
                       parallel >= 3.1 && < 3.3,
                       qd >= 1 && < 2,
@@ -146,4 +148,4 @@
 source-repository this
   type:     git
   location: git://gitorious.org/ruff/gruff.git
-  tag:      v0.3.3
+  tag:      v0.3.4
diff --git a/src/Shader.hs b/src/Shader.hs
--- a/src/Shader.hs
+++ b/src/Shader.hs
@@ -1,29 +1,30 @@
 module Shader (shader) where
 
+import qualified Data.ByteString as BS
 import Graphics.Rendering.OpenGL
 
 shader :: Maybe FilePath -> Maybe FilePath -> IO Program
 shader mV mF = do
-  [p] <- genObjectNames 1
+  p <- createProgram
   vs <- case mV of
     Nothing -> return []
     Just v -> do
-      [vert] <- genObjectNames 1
-      source <- readFile v
-      shaderSource vert $= [ source ]
+      vert <- createShader VertexShader
+      source <- BS.readFile v
+      shaderSourceBS vert $= source
       compileShader vert
 --      print =<< get (shaderInfoLog vert)
       return [vert]
   fs <- case mF of
     Nothing -> return []
     Just f -> do
-      [frag] <- genObjectNames 1
-      source <- readFile f
-      shaderSource frag $= [ source ]
+      frag <- createShader FragmentShader
+      source <- BS.readFile f
+      shaderSourceBS frag $= source
       compileShader frag
 --      print =<< get (shaderInfoLog frag)
       return [frag]
-  attachedShaders p $= (vs, fs)
+  attachedShaders p $= (vs ++ fs)
   linkProgram p
 --  print =<< get (programInfoLog p)
   return p