Hard light / soft light / specular light / diffuse light / by Xuan Prada

These days we are lucky enough to apply the same photographic and cinematographic principles to our work as visual effects artists lighting shots. That's why we are always talking about cinematography and cinematic language. Today we are going to talk about some very common techniques in the cinematography world: hard light, soft light, specular light and diffuse light.

The main difference between hard light and soft light do not eradicate in the light itself but in the shadows. When the shadow is perfectly defined and opaque we talk about hard light. When the shadows are diffuse we called it soft lighting, the shadows will also be less opaque.

Is there any specific lighting source that creates hard or soft lighting? The answer is no. Any light can create hard or soft lighting depending on two factors.

  1. Size: Not only the size of the practical lighting source but also the size in relationship with the subject that is being illuminated.
  2. Distance: In relation to the subject and the placement of the lighting source.

Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit. It is defined as the bending of light around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle.

When a light beam impacts on the surface of an object, if the size of the lighting source is similar to the size of the object, the light beam will go parallel and get slightly curved towards the interior.

If the size of the lighting source is smaller than the object or it is placed far away from it, the light beam won't bend creating very hard and defined shadows.

If the lighting source is bigger than the subject and it's placed near of it, the light beam will get curved a lot generating soft shadows.

If the lighting source is way bigger than the subject and it's place near of it, the light beam will be curved a lot, even they will get mixed at some point. Consequently the profile of the subject will not be represented in the shadows.

If a big lighting source is placed very far of the subject, its size will be altered in relation with the subject, and its behavior will be the same as a small lighting source, generating hard shadows. The most common example of this is the sun. It is very far but still generates hard lighting. Only on cloudy days the sun lights gets diffused by the clouds.

In two lines

  • Soft light: Big lighting sources and or close to the subject.
  • Hard light: Small lighting sources and or far from the subject.

Specular light: Lighting source very powerful in the center that gradually loses energy toward its extremes. Like a traditional torch. It generates very exposed and bright areas in the subject. Like the lights used in photo calls and interviews.

Diffuse light: Lighting source with uniform energy all over its surface. The lighting tends to be more compensated when it hits the subject surface.

Diffuse light and soft light are not the same. When we talk about soft lighting we are talking about soft shadows. When we mention diffuse light we are talking about the distribution of the light, equally distributed along its surface.

Some 3D samples with Legos.

  • Here the character is being lit by a small lighting source, smaller than the character itself and placed far from the subject. We get hard light, hard shadows.
  • Here we have a bigger lighting source, pretty much same size as the character and placed close to it. We get soft lighting, soft shadows.
  • This is a big lighting source, much bigger than the subject. We now get extra soft lighting, losing the shape of the shadows.
  • Now the character is being lit by the sun. The sun is a huge lighting source but being placed far far away from the subject it behaves like a small lighting source generating hard light.
  • Finally there is another example of very hard light caused by the flash of the camera, another very powerful and concentrated point of light placed very close to the subject. You can get this in 3D reducing a lot the spread value of the light.
  • Now a couple of images for specular and diffuse light.