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J
Jolyun
Participant
August 10, 2023
Question

How do I apply effects based on luminosity?

  • August 10, 2023
  • 1 reply
  • 422 views

I'm trying to figure out how to apply an effect (time displacement) to my clip based on the brightness of the clip. In areas where the image is bright, the effect should be fully at work. In areas where the image is dark the effect shouldn't be applied. Could anyone help me with a process to do this?

 

1 reply

R
Community Expert
Rick GerardCommunity Expert
Community Expert
August 10, 2023

Duplicate the footage layer. If the footage has been trimmed, pre-compose the top copy to move all attributes to the new comp, trim the comp to the layer length, and name it Time Matte. Apply the Black And White filter to the Time Matte layer. You may want to add Curves, Gaussian Blur, or other color effects to help you generate a good matte layer. You can then turn off the layer or move it to the bottom of the timeline.

 

Add an adjustment layer to the comp. Set the Time Matte layer as a Luma track matte for the adjustment layer.

 

Apply effects to the Adjustment layer. The track matte will limit the intensity of the effects you add.

 

If you are using Effects/Time/Time Displacement, you don't need the adjustment layer because Time Displacement uses a Time Displacement Layer to control the effect. Apply the effect to the source footage and select the Time Matte layer plus Effects and Masks as the Time Displacement Layer.

 

Let us know if you have any problems with this workflow.

 

 

rpiantanida
rpiantanida
Participant
September 27, 2025

Hi Rick, or anyone else who can solve this same question for a different effect.

 

I am needing to apply 2 different types of distortion (turbulent displace and wave warp), one to foreground and one to background. 

 

Using a standard depth map (i generate them in resolve) works almost, but where foreground transitions to background (the grey areas) the effect is being applied with lower transparency (like you would think). However this causes the image to double up, where you see half original undistorted footage and distorted footage layered over each other, creating a poor faux bluriness zone in the image.

 

Im looking everywhere but not seeing anyone asking this specificall. I am wanting to use a depth map, to map the intensity (wet vs dry) of the dostortion effects, as opposed to the transparency of the effect(at constant intensity).

 

This seems like a no brainer need, as you cannot get totally realistic looking depth of field by using tranparency and constant blur level. You would need to use the data to control amount of blur, with the effect being full opactiy.

 

Im hoping there is a simple solution, or even some legnthy expressions that can do what i am talking about.

 

attached screenshot you can see the doubled up images from the effect using the depth map just a transparency data.

Thanks in advance

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