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Color key masking in after effects9/2/2023 ![]() ![]() Managing Multiple MasksĪ few features in After Effects exist specifically to help you manage multiple masks in a single layer. Thus applying these modes to the top mask in the stack has no effect. Remember that masks render from top to bottom, so each mask's mode applies to its relationship with the layers above it. Keep these in mind when combining multiple feathered or semi-transparent masks. No pixel within the combined masks will have a value that is not already represented in one of the overlapping masks either the lighter or the darker of the two will be represented.įigures 3.20a and b With a Lighten (a) or a Darken (b) mask, the transparency values are chosen either from the mask set to this mode or those overlapping it, depending on which has the lighter (higher) or darker (lower) values. That's when Lighten and Darken modes come into play.įigures 3.20a and b show the result of using each of these modes they prevent mask densities from building up the way that they do with the other modes. When combining masks that have semi-transparent areas, either because the opacity of the masks is less than 100% or, as in the examples shown here, because the edges are heavily feathered, you may not want densities to have a linear relationship, building them up. In the digital world we sometimes speak of masks and alpha channels as having "density," and overlapping semi-transparent areas must be managed to avoid having the densities build up in undesirable ways. It is therefore the inversion of opacity or alpha values the higher the density, the less light is transmitted. ![]() "Density" is traditionally a film term describing how dark (opaque) the frame of film is at a given area of the image. ![]() The Subtract mask will now operate as expected if its opacity is lowered from 100%. The workaround is to add a mask at the top of the stack, set to Add mode, giving the mask the dimensions of the entire layer (double-click the Rectangular Mask tool). This is the identical result to applying the same mask in Add mode with Invert checked, although in that case the behavior is at least anticipated. But instead of the anticipated result, displaying the layer at full opacity and the masked area at 50%, the masked area is subtracted 100% and the rest of the layer displays at 50% opacity! You create a mask for the area to be dialed back, set it to Subtract, and set Mask Opacity to 50%. Say there's one part of an overlaid element that you want to mask and reduce to partial opacity, perhaps 50%. That way you can do a chroma key + some rough masking by hand.Does a bug still count as a bug if the development team knows about it and has decided to leave it as is to be backward-compatible? I'll let you be the judge. If you want to isolate the guitar player and the guitar, you can do this by covering the guitar in blue painters tape and shooting against a solid color background. If you have the opportunity to shoot your footage then you can save yourself a few weeks of work by shooting intelligently. Often breaking the task into a few passes (head, torso, arms, legs) can go faster than trying to mask it all at once, since changes to any one feature will be smaller than the overall change in pose. You can do the same thing with individual body parts to limit your work to adapting the masks on a frame by frame basis rather than moving and then adapting the mask. If the source video is quality, you can do some operations to help, like for the guitar, you can try motion tracking it so that you only need to adapt your mask when the guitar tilts and effectively changes shape. ![]() For that footage, you go frame by frame, keyframing masks for each. jimmi hendrix archival footage, then you don't have a lot of options to work intelligently - since the colors are muted, the quality is low, and the footage was never shot with rotoscoping in mind. So the most basic, tautological answer is that you rotoscope it, which means different things depending on the footage: ![]()
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