Why does the color Red suck so bad?

W

Whathafa

Member
So, I've noticed that in DV, DVCPro 50, and even DVCPro HD, the color RED -- pure red, especially -- looks like absolute shee-ite. For example, a red stoplight, or a red shirt, or whatever. It gets aliased to the bejesus and looks terrible. Can anyone explain to me why? Is this a flaw of the compression? Is there a setting I should change?

I'm fairly certain it's not an HVX200 problem, but probably a codec problem. For example, I used a scan converter, pushing component video out to the Firestore FS-100, recording in DV. No HVX involved at all, and the same RED problem occurred. Is this FCP's shortfall? The codec?

Anyone...?
 
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I've noticed similar things in my footage and other people's stuff. There definatly seems to be some real aliasing issues when you are shooting something that is pure red (T-shirts in general). Someone once suggested that this may well be from the limitations of pixel shifting. When the subject is made up of different primary colors, pixel shift can give you theoretically 1.5 times more resolution under the best circumstances. On the other hand, with primary colors the gain is diminished. This may be why there are issues with pure Red (never seen any with blue or green but that may be because it's less common to have pure blue or green stuff). This pixel shifting issue would explain why Red would have an issue in 1080p or 720p but not in DVCPro50 or DV where there are already way more than enough pixels to go around. I only shooting in HD so I don't know of issues in SD formats.
 
Just looked at some of my stuff that actually did have some pure blue and it looked fine. In fact, there's one shot which has a pure blue playground slide with a kid wearing a pure red shirt in front of it. The blue looks great but the red definatly has issues. I guess it's probably not the pixel shifting but some form of codec issue.
 
It has everything to do with the 4:1:1 color space of DV. Not sure why, but If I've learned anything from these forums its that.
 
Actually, there is a problem with just about any pure color. I've seen it on it's worst on blue and red, but also on yellow and green. Use Chroma blur to solve it, it blurs out the aliasing.
 
I haven't seen it on anything higher than DV either... Thought it was just about unnoticeable in 4:2:2.
 
It's an NTSC problem, not a camera problem and not a color space issue, a D1 4:4:4 signal would have the same effect. You just need to tone down the saturation a bit.
 
no i mean
i have shot factory settings

exported it, watched it on DVD, i never had any issues ore resolution loss in the Reds, or any pure colors.
 
Did you white balance properly? Using the 5.6k and 3.2k presets somethimes brings this effect...
 
i've had issues with red, as well. -- at first i thought this thread was all about how much the Red One camera sucked... I was astonished! Thank god it's not!!
 
Tone down the saturation? When? In the camera? In post?

It seems like then I would be sacrificing the other 999,999 colors just to fix a RED problem...
 
It's not an NTSC problem
It's not a pixel shift problem
It's not a DVX problem, or an HVX problem

It is a codec problem, and occurs more than you think. The main reason that most people never see it is becasue it doesn't really show up on an interlace TV. If have have a production monitor hooked up to your editing system you may see nasty red aliasing on your computer monitor, but not on your TV monitor.

This happens in most cameras that have the ability to capture saturated colors, and against popular belief, especially in 4:1:1 color space, it does happen with other colors as well, especially overly saturated blues, but not nearly as much as red.

The solution to this has already be stated, use a slight chroma blur filter and your good to go.
 
Scharky,

Could you please give me a little more info on the chroma blur filter? Is this in the Scene File on the HVX, or is this something to apply in post? Thanks a lot for your help.
 
This is something that you would ad in post. most modern NLE's today have it in some form or another. which NLE are you using?
 
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