I want to make certain shadows more prominent (using Cycles) without further illuminating the rest of the scene.

Example: I have a simple studio with a bowl of fruit and 3-point lighting. The light looks great so I don't want to change it but I want the bowl to cast a darker shadow on the ground (without dimming the back-light).

Alternatively, and this would be really cool, an anti-light source. Like a spot light that throws darkness instead of light. (Am I crazy for wanting this?)


up vote 11 down vote accepted

You have three options.

  1. You could add a light that is only visible to the shadow path, so it won't add any light, but it will cast shadows. If you're happy with the scene otherwise, you should duplicate one of the existing lights and move it forward or back just a touch.

  2. Another option is to add a "negative light", where you add a light with a color of white, and a negative value for the strength. There aren't such things in real life (except maybe black-holes) but for some lighting effects it is a neat trick to add darkness.

  3. Lastly you could do something with render layers, and render passes to get the shadow on it's own render layer and then control how dark it is during composting.

  • 4
    To make a negative lamp in cycles you must set the Strength to a negative number. Setting it to black will effectively disable it. – gandalf3 Apr 27 '14 at 19:09
  • Ah, yes. edited to fix my answer. – J. A. Streich Apr 28 '14 at 19:33

Using Light Paths

Without adding any more lights to the scene, you can play with the light paths node for the existing lights. For example, in this scene with only one light source and no ambient lighting the darkness of the shadows is determined by the light bouncing on other objects. enter image description here

By adding a light path node to the light, you can separate direct light (green) and indirect lighting (red) using with two different emitter shaders in the same light. enter image description here

By moving the values on the emitter, now you can control how dark your shadows are. You can even use negative values! enter image description here

for additional info on light paths check out Bartek Skorupa's tutorial: http://cgcookie.com/blender/2013/02/26/blender-cycles-light-path-node/


You could also use Compositing:

By enabling the AO and Shadow passes in Renderlayers > Passes:

enter image description here

You can use these in the compositor to darken parts of your image. For example:

enter image description here

You can achieve a wide variety of effects with the compositor and render passes (this is only a basic example). If you use renderlayers you can do even more, such as only affecting the shadows cast on the floor plane (see this question).

A nice advantage to using compositing is that you can tweak things without re-rendering.


Another thing you can try that hasn't already been covered by the other answers is Bounces:

Here is an example comparing 0 to 3 glossy and diffuse bounces (Render settings > Light Paths > bounces):

enter image description here

Note that you can also set the bounces per-shader with the lightpath node.

Disabling Caustics can also result in a slightly darker image.

If you are using Cycles and just want to make all shadows in the scene darker, you can simply use the new "Clamp Indirect" option. By setting it to a very low value (eg. 0.01) you can minimize the amount of indirect light that brightens shadows, thus making them darker:

very low clamp indirect darkens shadows

You can modify the materials properties of the table so that the shadows cast on it are darker.

If you turn down the shader for 'ambient' and turn it up for 'diffuse' then you will have your higher contrast shadow. You will also be able to do this without adding contrivances to your scene (e.g. magic invisible negative lights).

info here: http://wiki.blender.org/index.php/Doc:2.6/Manual/Materials/Properties/Ambient_Light_Effect

In the compositor

You can use the ASC-CDL node to alter the values of the rendered image to increase contrast

enter image description here

Read: What is the the ASC-CDL node?

Using color management.

If you are using Filmic Blender, you can use a High contrast or very high contrast look.

enter image description here

As an alternative you can create a LUT that alters the contrast the way you want and create a new stanza in the config.OCIO

Read: How to make 3D LUTs and use them in Blender?

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