Filming Question: Why does grain appear only in some scenes?

[Aoi Kurenai]

I was watching the Goggle-V movie and something I notice here, and well in a lot of older shows, has been bugging me. Why is it that only certain scenes have this terrible amount of grain on them? Sometimes scenes will go from crystal clear quality to having grain everywhere to having just a bit of grain. I've noticed this mostly happens in the action scenes, does anyone know why?

Examples of grain shots ranging from decent to really obtrusive -

http://i.imgur.com/kn2Ge.jpg
http://i.imgur.com/GlAH7.jpg
http://i.imgur.com/C8ndd.jpg
http://i.imgur.com/k0rUd.jpg
http://i.imgur.com/zIt9E.jpg

Examples of clear shots -
http://i.imgur.com/RRNtb.jpg
http://i.imgur.com/Wq4Hz.jpg
http://i.imgur.com/JEtwK.jpg
http://i.imgur.com/Ck5uL.jpg
http://i.imgur.com/eeLFK.jpg

(these are from the blu-ray release so they might be clearer than normal, but the concept is the same)

 

[Igadevil]

Is the grainy stuff all footage taken from the TV show and given the pan & scan treatment, or is it newly-shot? I dunno about that movie, but that's usually how it works with the Riders (that, or if it's stock footage from the archives.)

 

[Toku Prime]

Film grain is dependant on the chemical composition of that particular roll of film. Some film has a slightly different compostion and is more prone to graining than others. Look up "film grain" on wikipedia for all the details. The only way to know in advance would be to film a little bit, develop it and see how good (or not) it was for every single roll of film (and that assumes the chemical composition is consistent throughout the entire roll).

Assuming that Goggle-V was recorded on actual film (I wouldn't know if/when recording onto videotape became common in Japanese TV), I'd guess that they would record a scene using only a single camera, loaded with one roll of film. If they develop that film and it turns out that the film is grainey, the entire scene will be. There would be no way to alter it short of going back and re-recording the scene with a different roll of film, which they probably wouldn't have the time for on a weekly series. Other scenes would be recorded with different rolls, so the amount of grain on those scenes would be different. Once the film has been edited together to form the complete episode, you end up with the grain levels changing from scene to scene.

 

[KingWilly]

The grainy shots are special effects shots, while the non-grainy ones are not.

Special effect shots needed to be processed using optical effects, and since they are very old special effects that were made for a TV show with a strict schedule and a low budget, not a lot of effort had to be made to make a scene work on a tiny analog TV screen (they did not expect the show to ever be seen with detail as big as Blu-Ray).

This happens everywhere, from American movies like Back to the Future (which the soft-looking side-effect from optical effects made various shots seem blurrier) and even from later Sentai series (even as late as Jetman, the special effects scenes were blurrier and softer than those that didn't use any).

If the movie used pan and screen stock footage from the TV show (as is very common from these shows, even as late as the Dairanger movie and even 199 Heroes), then the grain will be very noticeable.