1. Open your clip in Vegas.
2. Create a new layer above the clip.
3. Right click on the empty space and choose "Insert generated media". Choose "Color gradient".
4. First set the angle to 90, then choose your colors. You can change the transparency from the slider on the left.
5. Next, set the compositing mode of the top layer to overlay by clicking the green little box with the symbol α.
6. You can control the overall brightness by changing the opacity of the top layer. 70-90 was used throughout Meatshot Vol. 2. It depends on the clip.
7. Add the effect "Levels" to your video clip and experiment with different settings. I like to add a little contrast to make that shit pop.
Additional stuff:
- "Unsharp mask" can be used to sharpen the image, but it will affect the colors a bit.
- Make your bottom layer "compositing child" so that layers below the clip will not be affected by the compositing mode of the top layer.
- Try duplicating the clip, setting the compositing mode to "Add", then creating the color gradient layer on top of those two. This gives the video more brightness and allows for more interesting looks (it'll also increase your rendering time)
- Glow, use sparingly please.