Often times when you’re creating an image and using the track matte process, you’ll be using a luma matte. The luma matte option uses the luminance values in an image (the black and the white) to create the matte. In one of the projects, this ink texture was used which has been stripped down to black and white to create a reveal using the luma matte method.
However, we had to use the inverted luma matte option because when you’re working with luma matte, the parts of your image that you want to reveal need to overlap with the white pixels and the parts you want to hide should overlap with the black ones. Unless of course you choose the “invert” option which will simply reverse that requirement.
The hardest part about the track matte workflow is that the layer you’re using for its luminance is not the layer for which the settings change. The settings change for the layer beneath it. As you can see in this example, the stacking order starts with the luminance layer and below that is the layer that you want to be cut away with those luminance values. Below that, there can be more layers that have background information.
Tips and Tricks for Track Matting
There are also some major tips that will help you when you’re working with track mattes on your own. First, remember that Levels are your best friend when creating a Luma Matte. You can use this effect to increase the contrast in your footage and push the mid-tones to make up their mind! When you have too many mid-tone values your image will have partial transparency which is good in moderation but you want more contrast overall.
Another tip to keep in mind is that you can use a different channel other than the alpha channel if you’re doing an alpha matte. The shift channels or set channels effects will allow you to re-route the channel you want to the alpha channel slot. This can come in handy if you don’t have an alpha channel but you have amazing contrast in maybe the blue channel. You can simply tell the blue channel to be the alpha channel and voila, you have an alpha matte!
Yet another trick is to animate a track matte layer to move along with the layer that it’s matting. If you’ve already animated the matte layer try parenting the matted layer to it and check out the results. If you’re using footage as a matte this will not always work.
One of the things they did in the True Detective titles was to project the footage onto 3D geometry that mimicked the shape of the matte layer. This is a time consuming process, but the results as you can see are awesome and the movement you get from adding in that extra detail brings so much more depth to a composition than just using a basic track matte.
Whether you’re just getting started with track mattes or you’re a seasoned pro, you can be sure that it’s a process that’s not going away. Especially after seeing some of the amazing results in the True Detective spot, we can’t get enough of this fresh take on an old trick. Be sure to implement these tips into your next project to see the added benefits it has on your track mattes!
Do you have any tips for your track matte process? Leave them in the comments below!