How this glow effect was created in cel-shaded anime? I sometimes see this glow in the old stuff. Curious if this technique has a name, and how this was made.



If you have something like documentary about technical and business aspects of anime, it would be appreciated.

A few extra examples, all from rurouni kenshin second opening:






And this:
All your screenshots look like conventional cel animation, but done with various different techniques. The first image the "glow" looks like it was painted with an airbrush, probably on its own cel sheet overlaying the rest of the image. The lens flare effects in your second and fourth screenshots look they were painted on separate cel sheets and then optically faded in and out to animate them and then combined with the background using multiple exposures. The glow of the candles in the third image was probably airbrushed on the same cel as the candle flames. I'm not sure how the animated sunlight falling on the water in the fifth image was done, but my guess it was simply hand painted. The last image with the glowing bar was probably done with an airbrush similar to the previous examples, though it could be that a diffuser was placed in front the camera lens.