Darby Edelen
Forum Replies Created
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Some applications treat Alpha Channels as transparency. Photoshop does not. If you want to use an Alpha Channel as a transparency in Photoshop then you’ll likely want to record a couple of actions as it can be tedious if you have to do it for several images.
The process is:
1) Remove any locks from your layer (you can drag it to the trash icon in the layers panel).
2) Make a selection from the alpha channel (you can cmd/ctrl click the channel).
3) Apply your selection as a layer mask to your layer.
4) Remove any pre-multiplication by first applying the layer mask then using Layer > Matting > Remove Black/White Matte.
This can be a pain. However, Photoshop will use Alpha Channels for a lot of things other than transparency and can’t simply assume that the alpha is transparency. I wish there were an easier way to convert an alpha to transparency in your case, but if there is I haven’t found it!
Darby Edelen
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[Ashish Gupta] “so if u want to have an animated displacement map u have to precompose along with your animation in and in your case tracking…”
You can pre-compose and Leave Attributes and set the pre-comp’s collapse transformations switch on. I do this a lot for these sorts of animation unaware effects (Displacement Map, Compound Blur, Set Matte, etc.)
The advantage is that you can animate in the parent comp without having to drill down into the pre-comp.
You may need to move some effects into the pre-comp depending on what your set up is. The displacement map will see the transforms in the parent comp but not the effects.
Darby Edelen
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[josef brett] “It’s frustrating as I have tried pre-comping the dancer etc and nothing works!”
Enable collapse transformations on the pre-comp.
Darby Edelen
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Todd’s suggested book is a good one.
I recently had a lot of keying to do and had the opportunity to try a few different keyers.
I’m most familiar with and comfortable with Keylight, which is a color difference keyer.
Ultimate is also a color difference keyer and works on the same fundamental principal as Keylight(although with a somewhat different approach).
There’s also Primatte which takes an entirely different approach to keying in terms of what’s under the hood. Conceptually it uses 3 different polyhedrons that contain color values which correspond to the solid, transparent and spill colors. Most of the adjustments you make to key internally deform these polyhedrons. I was very impressed with Primatte initially but found it difficult to massage the key into something I was satisfied with.
I also tried out the Image Based Keyer (IBK) in Nuke which uses a clean plate to key. I assume this works somewhat similar to a difference key, but the results are pretty amazing. You can pull some fantastic edges even on a really messy green or blue screen. It seems that you really need to rely on another keyer to generate a core matte though.
That was a long winded post 🙂 I’d encourage you to look for training materials for some of these keyers (some of the better ones cover the theory to some degree).
Darby Edelen
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[Vishesh Arora] “If you double click on the camera to open Camera Settings, you will notice that the z-Position is equal to( negative of )Focus Distance.”
Just a quick not of clarification: it’s actually set to the -zoom value rather than the focus distance.
These are often locked together in the camera dialog.
Darby Edelen
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You’ve stumped me. The interface in that image looks like the Layer Viewer rather than the Composition Viewer, but the tab at the top of the panel very clearly states that you’re viewing a Composition.
When you create a new composition do you have the same problem?
Darby Edelen
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[Chris Vile] “Strange because it shouldn´t care if the mode is set to add or what ever when in use of a 3D-Obj?”
What do you mean by a 3D object? 3D layers should work properly, but there are several effects that are “3D” but render on a 2D plane. These do not get free interaction with 3D AE layers.
So how did you make your 3D lightscreen?
The more information we have the more helpful we can be 🙂
Darby Edelen
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The Normal blend mode is a standard alpha blend. The reason the colors don’t quite make sense in a simple mathematical relationship is because you’re not considering the alpha values.
If you assume ‘A’ is the top layer, ‘B’ is the lower layer and their alphas are ‘a’ and ‘b’ respectively then the resulting color is:
A*a + B*b*(1-a)
Opacity modifies the alpha of the layer.
Darby Edelen
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I can’t really tell from the still, but if I were approaching this I’d create the background, text and flare separately and comp them together.
Background looks like a combination of gradient elements and possibly a 3D floor plane.
Text looks like it’s got a gradient as well, possibly a spot light illuminating it.
The flare looks like it’s just comp’d in on top of everything. Apply it to a black solid and set it to Screen or Add if you prefer the overblown look.
Darby Edelen
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[Grant Wilber] “But what program/person is doing this kind of stuff and how much you think it would cost so I can entertain them?”
Why that’s Macaulay Culkin!
You might want to clarify what you’re asking.
Darby Edelen