New approach to levels, 16-255 ?

musicvid10 wrote on 1/25/2010, 8:58 PM
I've got five screens (two lcd, three crt) and five dvd players (three set top, two computer) in my home. and have spent a bit of time playing with some nicely-shot but conservatively-leveled footage shot of a recent event. It was from a professional shooter with lots of experience, but just a bit gunshy over the levels, IMO.

Synopsis: To make the best render-for-dvd on any player / screen combination, I had to expand the levels from the original footage, which was just a bit flat, errm. Gave me an opportunity to play.

0-255 looked great on the monitors, but too dark on the crt's. 16-235 looked OK on the crt's but a little flat on the monitors. 16-255 looked good on both, because 16 blacks are customary and acceptable on either, and the >235 whites get clamped (also acceptably) on the crt's.

Comments? I'm sure I've opened a can of worms on this one, but oh well . . .

Comments

farss wrote on 1/25/2010, 11:21 PM
Going below Y'=16 could be asking for trouble. Aside from that I always keep things reasonably legal. As you say though going over Y'= 235 is unlikely to cause major grief as most players will simply clamp the signal. I have no clue really as to what happens with playback on PCs or LCDs, there's too many user tweaks to reach any consensus. Again though I would say keep it legal that way even if the user has everything at 11 at least your content will look the same horrid mess that they're used to. Considering that some devices are now using variable PAR all bets are of regarding our 'artistic intent'.
The other comment I'd make is don't limit yourself to a linear transform, that's why I use curves.

Bob.
musicvid10 wrote on 1/26/2010, 8:39 AM
Right. Anything below 16 (except with fadeouts) isn't pleasant on a crt. I also have one crt that is touchy with the whites, but my new approach hasn't caused any blowout or buzzing on it, so I think I'm on safe ground here.

The other comment I'd make is don't limit yourself to a linear transform, that's why I use curves.

I'm using the Sony Levels plugin and the Gamma control provides all the "curviness" I need for these simple projects.
Jay Gladwell wrote on 1/26/2010, 9:08 AM

Not being at technical as Glenn Chan, for example, let me say I'm just musing here, nothing more, nothingless...

I own both a CRT and a LCD, both properly calibrated. When I watch (rarely) network programming, i.e., NTSC, on either it looks smashing. The same can be said about DVDs like Planet Earth (also engineered to NTSC standards).

All things being equal, and based on the information provided, it would appear there might be something amiss in your workflow/system/screens.


GlennChan wrote on 1/26/2010, 6:01 PM
I think you should try to have proper levels on what you create.

As bob/farss points out, if you go below 16 (Y') you can have problems such as older TV sets getting a rolling picture.

If you have values above 235 (Y'), that is not so awful. But some DVD players will clip everything about 235 (Y'), and others won't. Some TVs will clip above, others won't. Why do you want your audience to see a different picture depending on what DVD player and TV they have?

The example workflows at the bottom of this article explains how to make a proper master:
http://www.glennchan.info/articles/vegas/v8color/vegas-9-levels.htm

This article explains how to deal with superwhites:
http://www.glennchan.info/articles/vegas/color-correction/tutorial.htm


farss wrote on 1/26/2010, 6:52 PM
I think Glenn covers this in his excellent articles however just to be sure:
If your fade outs are going below 16 then you need to add a track of legal (16,16,16) black as your bottom track.

Bob.
Former user wrote on 1/26/2010, 7:05 PM
Bob brings out an important point about fades. I have been caught on this a few times. The fade will go to 0 black if you do not have 16 black track below.

Dave T2