Multiple Light Select outputs can be rendered for a single scene, and lights may be included in more than one Light Select render element.

By using the Light Select render element, specific lights in the resulting render can be captured and adjusted (color, temperature, brightness, etc.) in a composite without the need to re-render. For example, a Light Select element for all of the backlights in a scene, an artist may adjust the backlighting in the composite without affecting the rest of the scene's illumination.

UI Path: ||V-Ray|| > Render Elements > Light Select

How to add a render element to a scene

Enable Deep Output – Specifies whether to include this render element in deep images.

Color Mapping – Applies the color mapping options specified in the Color Mapping rollout of the V-Ray tab in the Render Settings window to this render element. This option is enabled by default.

Consider for Anti-Aliasing – When enabled, anti-aliasing is used where possible.

Filtering – Applies an image filter to this channel.

Vfb Color Corrections – Applies the post-render color adjustments made from the VFB.

Denoise – Enables the render element's denoising, provided the Denoiser render element is present.

Mode – Sets what type of lighting contribution is generated in the element as follows:

Direct illumination – Contains diffuse and specular information from the specified lights.
Direct Raw – Lighting within the VRayLightSelect element behaves as a raw render element.
Direct Diffuse – Lights output only their diffuse contribution and contain no specular information.
Direct Specular – Lights output only their specular contribution and contain no diffuse information.
Full – Lights provide full output for all information available in the scene, such as GI, SSS, reflection, refraction, etc.
Indirect – Lights output only the indirect scene lighting.
Indirect Diffuse – Lights output only indirect scene lighting that originated from the diffuse contribution of the specified lights.
Indirect Specular – Lights output indirect scene lighting that originated from the specular contribution of the specified lights.
Subsurface – Lights output only the information calculated from Subsurface Scattering materials.
Light Path Expression – Allows capturing custom light transport paths with regular expressions. 

Direct Diffuse Shadow – Outputs only the shadows cast by objects illuminated by pre-selected lights. This option has the same output as the Shadow render element. 
Direct Specular Shadow – Outputs the specular information from the shadows cast by objects illuminated by a pre-selected light. The objects that the shadows are cast on have to be with reflective material for this channel to be visible.

Light Path Expression – Allows you to enter a Light Path Expression when the Mode is set to Light Path Expression.

Matte Objects Only – When enabled, it renders only the shadows cast on matte objects illuminated by a pre-selected light.

Light Path Expression Builder – Opens the https://lpe-builder.chaosgroup.com/ webpage, available to help you compose expressions and track exactly which ray paths they capture.

Enable the arrow to enter a selection mode. Once enabled, you can select the lights from the viewport.

Emissive materials can also be added to this list. V-Ray respects VRayMtl with non-black self-illumination and VRayLightMtl.