diff --git a/src/camera.rs b/src/camera.rs
index cf606bc..a3188d8 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -61,18 +61,19 @@ impl<T: RealField> ImageSampler<T> {
     }
 }
 
-pub fn render_scene<T: RealField>(output_image: &mut ImageRgbF<T>, scene: &Scene<T>)
-{
+pub fn render_scene<'a, T: RealField>(output_image: &mut ImageRgbF<T>, scene: &Scene<T>) {
     let image_sampler = ImageSampler::new(
         output_image.get_width(),
         output_image.get_height(),
         scene.camera_location,
     );
+    let ambient_intensity: T = convert(0.0);
+    let directional_intensity: T = convert(0.9);
     let integrator = PhongIntegrator::<T> {
-        ambient_light: convert(0.1),
+        ambient_light: ColourRgbF::from_named(NamedColour::White) * ambient_intensity,
         lights: vec![DirectionalLight {
             direction: Vector3::new(convert(1.0), convert(1.0), convert(-1.0)).normalize(),
-            intensity: convert(0.3),
+            colour: ColourRgbF::from_named(NamedColour::White) * directional_intensity,
         }],
     };
     for column in 0..output_image.get_width() {
@@ -100,8 +101,9 @@ pub fn render_scene<T: RealField>(output_image: &mut ImageRgbF<T>, scene: &Scene
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::materials::Material;
+    use crate::materials::LambertianMaterial;
     use crate::raycasting::{Intersect, IntersectionInfo, Plane};
+    use std::rc::Rc;
 
     #[cfg(test)]
     mod imagesampler {
@@ -126,7 +128,7 @@ mod tests {
             let film_plane = Plane::new(
                 Vector3::new(0.0, 0.0, 1.0),
                 target.film_distance,
-                Material::<f64>::new_dummy(),
+                Rc::new(LambertianMaterial::<f64>::new_dummy()),
             );
             let point_on_film_plane = match film_plane.intersect(&ray) {
                 Some(IntersectionInfo {
diff --git a/src/integrators.rs b/src/integrators.rs
index db81330..5f7ceb8 100644
--- a/src/integrators.rs
+++ b/src/integrators.rs
@@ -9,20 +9,22 @@ pub trait Integrator<T: RealField> {
 
 pub struct DirectionalLight<T: RealField> {
     pub direction: Vector3<T>,
-    pub intensity: T,
+    pub colour: ColourRgbF<T>,
 }
 
 pub struct PhongIntegrator<T: RealField> {
-    pub ambient_light: T,
+    pub ambient_light: ColourRgbF<T>,
     pub lights: Vec<DirectionalLight<T>>,
 }
 
 impl<T: RealField> Integrator<T> for PhongIntegrator<T> {
     fn integrate(&self, info: &IntersectionInfo<T>) -> ColourRgbF<T> {
-        let intensity = self.lights
+        self.lights
             .iter()
-            .map(|light| light.intensity * light.direction.dot(&info.normal))
-            .fold(self.ambient_light, |a, b| a + b);
-        ColourRgbF::from_vector3(&(info.material.colour.as_vector3() * intensity))
+            .map(|light| {
+                info.material.bsdf()(info.retro, light.direction, light.colour)
+                    * light.direction.dot(&info.normal)
+            })
+            .fold(self.ambient_light, |a, b| a + b)
     }
 }
diff --git a/src/main.rs b/src/main.rs
index ebf8b6c..5162c76 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,10 +7,12 @@ use std::time::Duration;
 
 use nalgebra::Vector3;
 
+use std::rc::Rc;
+
 use vanrijn::camera::render_scene;
 use vanrijn::colour::{ColourRgbF, NamedColour};
 use vanrijn::image::{ClampingToneMapper, ImageRgbF, ImageRgbU8, ToneMapper};
-use vanrijn::materials::Material;
+use vanrijn::materials::LambertianMaterial;
 use vanrijn::raycasting::{Plane, Sphere};
 use vanrijn::scene::Scene;
 
@@ -61,18 +63,16 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
             Box::new(Plane::new(
                 Vector3::new(0.0, 1.0, 0.0),
                 -2.0,
-                Material {
+                Rc::new(LambertianMaterial {
                     colour: ColourRgbF::from_named(NamedColour::Green),
-                    smoothness: 0.0,
-                },
+                }),
             )),
             Box::new(Sphere::new(
                 Vector3::new(0.0, 1.0, 5.0),
                 1.0,
-                Material {
+                Rc::new(LambertianMaterial {
                     colour: ColourRgbF::from_named(NamedColour::Blue),
-                    smoothness: 0.7,
-                },
+                }),
             )),
         ],
     };
diff --git a/src/materials.rs b/src/materials.rs
index edc4194..a20391a 100644
--- a/src/materials.rs
+++ b/src/materials.rs
@@ -1,18 +1,36 @@
-use nalgebra::RealField;
+use nalgebra::{RealField, Vector3};
 
 use super::colour::ColourRgbF;
 
-#[derive(Debug)]
-pub struct Material<T: RealField> {
-    pub colour: ColourRgbF<T>,
-    pub smoothness: T,
+use std::fmt::Debug;
+
+pub trait Material<T: RealField>: Debug {
+    fn bsdf<'a>(
+        &'a self,
+    ) -> Box<dyn Fn(Vector3<T>, Vector3<T>, ColourRgbF<T>) -> ColourRgbF<T> + 'a>;
 }
 
-impl<T: RealField> Material<T> {
-    pub fn new_dummy() -> Material<T> {
-        Material {
+#[derive(Debug)]
+pub struct LambertianMaterial<T: RealField> {
+    pub colour: ColourRgbF<T>,
+}
+
+impl<T: RealField> LambertianMaterial<T> {
+    pub fn new_dummy() -> LambertianMaterial<T> {
+        LambertianMaterial {
             colour: ColourRgbF::new(T::one(), T::one(), T::one()),
-            smoothness: T::zero(),
         }
     }
 }
+
+impl<T: RealField> Material<T> for LambertianMaterial<T> {
+    fn bsdf<'a>(
+        &'a self,
+    ) -> Box<dyn Fn(Vector3<T>, Vector3<T>, ColourRgbF<T>) -> ColourRgbF<T> + 'a> {
+        Box::new(
+            move |_w_o: Vector3<T>, _w_i: Vector3<T>, colour_in: ColourRgbF<T>| {
+                self.colour * colour_in
+            },
+        )
+    }
+}
diff --git a/src/raycasting.rs b/src/raycasting.rs
index 59a80ba..861155f 100644
--- a/src/raycasting.rs
+++ b/src/raycasting.rs
@@ -2,6 +2,8 @@ use nalgebra::{convert, RealField, Vector3};
 
 use super::materials::Material;
 
+use std::rc::Rc;
+
 #[derive(Clone, Debug)]
 pub struct Ray<T: RealField> {
     origin: Vector3<T>,
@@ -22,26 +24,26 @@ impl<T: RealField> Ray<T> {
 }
 
 #[derive(Debug)]
-pub struct IntersectionInfo<'a, T: RealField> {
+pub struct IntersectionInfo<T: RealField> {
     pub distance: T,
     pub location: Vector3<T>,
     pub normal: Vector3<T>,
     pub retro: Vector3<T>,
-    pub material: &'a Material<T>,
+    pub material: Rc<dyn Material<T>>,
 }
 
 pub trait Intersect<T: RealField> {
-    fn intersect(&self, ray: &Ray<T>) -> Option<IntersectionInfo<T>>;
+    fn intersect<'a>(&'a self, ray: &Ray<T>) -> Option<IntersectionInfo<T>>;
 }
 
 pub struct Sphere<T: RealField> {
     centre: Vector3<T>,
     radius: T,
-    material: Material<T>,
+    material: Rc<dyn Material<T>>,
 }
 
 impl<T: RealField> Sphere<T> {
-    pub fn new(centre: Vector3<T>, radius: T, material: Material<T>) -> Sphere<T> {
+    pub fn new(centre: Vector3<T>, radius: T, material: Rc<dyn Material<T>>) -> Sphere<T> {
         Sphere {
             centre,
             radius,
@@ -51,7 +53,7 @@ impl<T: RealField> Sphere<T> {
 }
 
 impl<T: RealField> Intersect<T> for Sphere<T> {
-    fn intersect(&self, ray: &Ray<T>) -> Option<IntersectionInfo<T>> {
+    fn intersect<'a>(&'a self, ray: &Ray<T>) -> Option<IntersectionInfo<T>> {
         let ray_origin_to_sphere_centre = self.centre - ray.origin;
         let radius_squared = self.radius * self.radius;
         let is_inside_sphere = ray_origin_to_sphere_centre.norm_squared() <= radius_squared;
@@ -84,7 +86,7 @@ impl<T: RealField> Intersect<T> for Sphere<T> {
             location,
             normal,
             retro,
-            material: &self.material,
+            material: Rc::clone(&self.material),
         })
     }
 }
@@ -92,11 +94,15 @@ impl<T: RealField> Intersect<T> for Sphere<T> {
 pub struct Plane<T: RealField> {
     normal: Vector3<T>,
     distance_from_origin: T,
-    material: Material<T>,
+    material: Rc<dyn Material<T>>,
 }
 
 impl<T: RealField> Plane<T> {
-    pub fn new(normal: Vector3<T>, distance_from_origin: T, material: Material<T>) -> Plane<T> {
+    pub fn new(
+        normal: Vector3<T>,
+        distance_from_origin: T,
+        material: Rc<dyn Material<T>>,
+    ) -> Plane<T> {
         normal.normalize();
         Plane {
             normal,
@@ -107,7 +113,7 @@ impl<T: RealField> Plane<T> {
 }
 
 impl<T: RealField> Intersect<T> for Plane<T> {
-    fn intersect(&self, ray: &Ray<T>) -> Option<IntersectionInfo<T>> {
+    fn intersect<'a>(&'a self, ray: &Ray<T>) -> Option<IntersectionInfo<T>> {
         let ray_direction_dot_plane_normal = ray.direction.dot(&self.normal);
         let point_on_plane = self.normal * self.distance_from_origin;
         let point_on_plane_minus_ray_origin_dot_normal =
@@ -128,7 +134,7 @@ impl<T: RealField> Intersect<T> for Plane<T> {
             location: ray.point_at(t),
             normal: self.normal,
             retro: -ray.direction,
-            material: &self.material,
+            material: Rc::clone(&self.material),
         })
     }
 }
@@ -148,6 +154,7 @@ mod tests {
     }
 
     use super::*;
+    use crate::materials::LambertianMaterial;
     use quickcheck::{Arbitrary, Gen};
     impl<T: Arbitrary + RealField> Arbitrary for Ray<T> {
         fn arbitrary<G: Gen>(g: &mut G) -> Ray<T> {
@@ -188,49 +195,77 @@ mod tests {
     #[test]
     fn ray_intersects_sphere() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(0.0, 0.0, 1.0));
-        let s = Sphere::new(Vector3::new(1.5, 1.5, 15.0), 5.0, Material::new_dummy());
+        let s = Sphere::new(
+            Vector3::new(1.5, 1.5, 15.0),
+            5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(s.intersect(&r), Some(_));
     }
 
     #[test]
     fn ray_does_not_intersect_sphere_when_sphere_is_in_front() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(0.0, 0.0, 1.0));
-        let s = Sphere::new(Vector3::new(-5.0, 1.5, 15.0), 5.0, Material::new_dummy());
+        let s = Sphere::new(
+            Vector3::new(-5.0, 1.5, 15.0),
+            5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(s.intersect(&r), None);
     }
 
     #[test]
     fn ray_does_not_intersect_sphere_when_sphere_is_behind() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(0.0, 0.0, 1.0));
-        let s = Sphere::new(Vector3::new(1.5, 1.5, -15.0), 5.0, Material::new_dummy());
+        let s = Sphere::new(
+            Vector3::new(1.5, 1.5, -15.0),
+            5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(s.intersect(&r), None);
     }
 
     #[test]
     fn ray_intersects_sphere_when_origin_is_inside() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(0.0, 0.0, 1.0));
-        let s = Sphere::new(Vector3::new(1.5, 1.5, 2.0), 5.0, Material::new_dummy());
+        let s = Sphere::new(
+            Vector3::new(1.5, 1.5, 2.0),
+            5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(s.intersect(&r), Some(_));
     }
 
     #[test]
     fn ray_intersects_plane() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(-1.0, 0.0, 1.0));
-        let p = Plane::new(Vector3::new(1.0, 0.0, 0.0), -5.0, Material::new_dummy());
+        let p = Plane::new(
+            Vector3::new(1.0, 0.0, 0.0),
+            -5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(p.intersect(&r), Some(_));
     }
 
     #[test]
     fn ray_does_not_intersect_plane() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(1.0, 0.0, 1.0));
-        let p = Plane::new(Vector3::new(1.0, 0.0, 0.0), -5.0, Material::new_dummy());
+        let p = Plane::new(
+            Vector3::new(1.0, 0.0, 0.0),
+            -5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         assert_matches!(p.intersect(&r), None);
     }
 
     #[test]
     fn intersection_point_is_on_plane() {
         let r = Ray::new(Vector3::new(1.0, 2.0, 3.0), Vector3::new(-1.0, 0.0, 1.0));
-        let p = Plane::new(Vector3::new(1.0, 0.0, 0.0), -5.0, Material::new_dummy());
+        let p = Plane::new(
+            Vector3::new(1.0, 0.0, 0.0),
+            -5.0,
+            Rc::new(LambertianMaterial::new_dummy()),
+        );
         match p.intersect(&r) {
             Some(IntersectionInfo {
                 distance: _,
diff --git a/src/scene.rs b/src/scene.rs
index 7dc67d3..16ee56f 100644
--- a/src/scene.rs
+++ b/src/scene.rs
@@ -1,8 +1,8 @@
-use nalgebra::{RealField,Vector3};
+use nalgebra::{RealField, Vector3};
 
 use crate::raycasting::Intersect;
 
-pub struct Scene<T:RealField> {
+pub struct Scene<T: RealField> {
     pub camera_location: Vector3<T>,
     pub objects: Vec<Box<dyn Intersect<T>>>,
 }