Channel specific filter

An effect can be specific to a particular channel. In that case, if you want to affect a specific channel, you need to create an input AND an output which identifies this channel. As a general rule, the input / output structure should always respect a 1:1 rule. If you want to input a specific channel, you have to output the same channel.

Example of a filter affecting the basecolor channel only :

It is not possible to combine generic setup (input/output nodes) and specific channels (basecolor/basecolor).

Alpha component management

Channels stored as RGBA support alpha (basecolor for instance). For these channel, the alpha Input/Output can be stored directly in the Substance color output. However, the Substance engine does not support Alpha for grayscale images: it has to be managed using a secondary map. To get the alpha component of a specific channel in a substance graph, create a grayscale input named 'channelname_Alpha', example: basecolor_Alpha, roughness_Alpha and so on.
To output this alpha component, create an output node with the same name convention.

The specific "_Alpha" output per channel doesn't work with regular materials. To hide a channel with a mask, a specific output must be created with the following naming convention :

  • Identifier : channels_Alpha
  • Usage : channels_Alpha 

List of input/output usages and identifiers

It is possible to use either the usage or the identifier in an input node (the usage has the priority).

Channel nameUsageIdentifier / Identifier Alpha
Ambient OcclusionambientOcclusionambientOcclusion / ambientOcclusion_Alpha
Anisotropy Angleanisotropyangle anisotropyangle / anisotropyangle_Alpha
Anisotropy Levelanisotropylevelanisotropylevel / anisotropylevel_Alpha
Base Colorbasecolor 

basecolor / basecolor_Alpha

Blending Maskblendingmaskblendingmask / blendingmask_Alpha
Diffusediffusediffuse / diffuse_Alpha
Displacementdisplacementdisplacement / displacement_Alpha
Emissiveemissiveemissive / emissive_Alpha
Glossinessglossinessglossiness / glossiness_Alpha
Heightheightheight / height_Alpha
IORiorior / ior_Alpha
Metallicmetallicmetallic / metallic_Alpha
Normalnormalnormal / normal_Alpha
Opacityopacityopacity / opacity_Alpha
Reflectionreflection reflection / reflection_Alpha

roughness / roughness_Alpha

Scatteringscatteringscattering / scattering_Alpha
Specularspecularspecular / specular_Alpha
Specular Levelspecularlevelspecularlevel / specularlevel_Alpha
Transmissivetransmissive transmissive / transmissive_Alpha
User 0user0 user0 / user0_Alpha
User 1user1user1 / user1_Alpha
User 2user2user2 / user2_Alpha
User 3user3user3 / user3_Alpha
User 4user4user4 / user4_Alpha
User 5user5user5 / user5_Alpha
User 6user6user6 / user6_Alpha
User 7user7user7 / user7_Alpha


In this example the Base Color alpha channel is extracted via a grayscale node to overwrite the Roughness channel.

In this example the Roughness channel is multiplied over the Base Color.