Adjustment layer blend mode only works when an effect is active

[Horshack]

I noticed this behavior and was wondering if it was by design or a bug. If I add an adjustment layer and change its blending mode, the blending mode is not visibly applied to the layers beneath. However, if I then add any effect to the adjustment layer the blending mode starts working. It can be any effect, even one whose parameters have no modifications to the adjustment layer, such as a hue/saturation effect dialed to the default master hue of zero. If I then disable the effect by clicking the Fx column on the layer then the adjustment layer reverts back to not honoring the blending mode.

Btw if I repeat this same procedure on Photoshop the blending mode is applied/visible.

[Rick Gerard]

Think about it. How many pixels are there in an adjustment layer to blend with the pixels in the layers below?

Nothing wrong here.

[Horshack]

@Rick, an adjustment layer is a composite of the layers beneath it, so it has all the pixels of the layers beneath it. And as described, the blending mode works after I've added a do-nothing effect to the layer, which does not affect the content of the layer (ie, doesn't add "pixels" to it).

[Mylenium · Accepted solution]

You have a wrong understanding of how adjustment layers in AE work. They are an empty container. They are not doubling the buffer. The actual accumulation of pixel data is triggered by the effect, not the layer. It works as it is designed within AE's general logic. And of course even if it would work as in PS, it would have almost zero benefit since due to how AE's render pipeline works, you may still need to introduce some step that "flattens" the intermediate buffers, i.e. pre-composing or additional layers. Even if you don't pre-compose, clearly what you want can already also be done by using specific effects like Channel Compiner or CC Composite on normal solids. One therefore might argue that your workflow is kinda crooked on some level even, but "whatever works..."

Mylenium

[Horshack]

Mylenium​, thanks. I re-read Adobe's description of adjustment layers and it's consistent with what you wrote - they frequently use the word "effect" to describe the compositing behavior. One might argue though that a non-default blending mode should trigger a composite as well. I agree the CC Composite achieves the same result - it was more a curiosity for me than a workflow impediment. Thanks again for the reply.

[Rick Gerard]

I stand by what I said, an adjustment layer has no pixels so there is nothing to blend until you create some by adding an effect. Only then will there be some pixels to blend. As Mylenium said, your understanding is flawed. Everything works as designed.