2 Replies Latest reply on May 4, 2011 9:01 AM by hillaryknox

    Multiple adjustment layers vs. multiple effects on a single adj. layer

    hillaryknox

      I posted this earlier on the Creative Cow forums, and came back with inconclusive answers...

       

      If I have the exact same clip in 2 separate comps...In Comp 1 I have 5 color correction effects on a single adjustment layer, and in Comp 2 I have 5 adjustment layers with the same effects, 1 effect each spread over the 5 adjustment layers (in the same order). Should I theoretically expect to get the exact same image in both comps?

       

      Here's the reason I'm asking. I'm doing some color correction that occasionally involves a lot of keying, which I'm doing in Colorista II. It's not green/blue screen keying, it's keying the shot footage for adjustment, e.g. skin tones, backgrounds, blown-out highlights, etc. I'm finding that in order for the Colorista II keyer to work based on previous instances of effects calculations (i.e. Levels, Hue/Sat, or other Colorista instances, all of which occur *before* the key) I'm having to put it on another Adjustment Layer for the keyer to take the earlier effects into account. Otherwise, if it's on the same adjustment layer, the Colorista keyer disregards the previous effects & uses the un-effected clip as the source for the key.

       

      I don't know if this is just the way the Colorista II keyer works, or if this is a global After Effects-wide order-of-operations thing that I don't fully have a handle on. I understand order of operations, and that Adjustment Layers affect all layers below it, and all that stuff. My question is, what (if anything) is the difference in behavior between multiple effects on a single adjustment layer vs the same effects spread out over multiple adjustment layers? Is it predictable & consistent? Or is it just common knowledge (to everyone else but me) that sometimes you have to use multiple adjustment layers based on the specific effect combinations that you're using?

        • 1. Re: Multiple adjustment layers vs. multiple effects on a single adj. layer
          Mylenium Most Valuable Participant

          I don't know if this is just the way the Colorista II keyer works, or if this is a global After Effects-wide order-of-operations thing that I don't fully have a handle on.

           

          As far as I understand the SDK, it is not considered practical, since it would require a plug-in to establish its own comp buffer outside the main rendering pipeline, which could lead to issues with color consistency and things like premultiplied vs. straight Alpha. I also seem to remember that as of CS5 it is actually no longer technically possible. Hence effects that use specific source footage API calls will bypass any previous effects and directly operate on the source.

           

          My question is, what (if anything) is the difference in behavior between multiple effects on a single adjustment layer vs the same effects spread out over multiple adjustment layers? Is it predictable & consistent?

           

          The result should be the same under all circumstances, assuming all adjustment layers have the same opacity and no masks and their stacking order is equal. Only when you apply masks or adjust the opacity to fade specific adjustments you will see differences. It is also to note that having all effects might be a bit faster and more efficient, since less data is passed from buffer to buffer...

           

          Mylenium

          • 2. Re: Multiple adjustment layers vs. multiple effects on a single adj. layer
            hillaryknox Level 1

            Ok, interesting.

             

            I'm just saying, for certain, that the keyer in Colorista, when operating in the first adjustment layer (with or without other effects before it) will use the un-effected source to pull the key, whereas if it is on a second adjustment layer, it uses the source plus the effects on a lower adjustment layer to pull the key...which, in my case is a good thing, because I need to be able to use things like Levels & Hue/Saturation prior to doing the key - and doing that all on one adjustment layer doesn't really work.

             

            As for it being faster & more efficient, I don't doubt that for a minute. AE can turn into a sluggish beast when doing a lot of color correction.