Color Correction! Is there a basic foundation?

[Mike Kujbida]

Originally Posted by Richard Jones

In the RGB world 255 represents extreme white (fully opaque) and 0 extreme black. (fully transparent). That is an RGB of 0,0,0 will produce white and of 255,255,255 will represent black.

Richard, you may be referring to alpha channel levels.
I was taught that an RGB value of 0-0-0 is pure black while 255-255-255 is pure white.

[Mike Kujbida]

Originally Posted by Adam Stanislav

Hue is actually an angle on the color wheel. It determines what color a pixel has regardless of its luminosity or saturation. That is, its value, while numeric, represents things such as red, green, orange, etc.

Thanks for the clarification Adam.

[Richard Jones]

I think I'm trying to say something similar in that the RGB figures represent the colour values of R,G and B with the mix between them and the differing values leading to different colours or, if used within only a single R, G or B field, the intensity (value) of that colour. Hence the 16,777,216 steps you both refer to but Adam is right in that the hue itself is identified from its angle on the colour wheel.

To go back to the start of the debate, the chart (which has attracted a number of favourable comments from experienced colourists who have said that they wished they might have had a similar aide memoire when they were starting to explore what is a huge subject in its own right) was designed to give brief introductory guidance and to help the beginner take the step to the next level. It was never intended, nor could it ever be, a comprehensive or infallible guide to the subject as a whole

Richard

[David Ruhland]

you guys are speaking different language here right now. Someday I hope to learn what your talking about...

[Mike Kujbida]

David, the DVD referred to in this thread is $60 and both books are less than $30 each.
All of them are very worthwhile investments in helping you to better understand what can be a very confusing topic.
I have the DVD and have watched it several times.

[Adam Stanislav]

Originally Posted by David Ruhland

Someday I hope to learn what your talking about...

Let's make it today, ;)

If you look at the Sony Vegas vectorscope and move the cursor over it, a yellow line connects your cursor position with the center of the vectorscope (see the enclosed image, though unfortunately it does not show the cursor itself, but in this case I held the cursor at the point where the two withe lines connect).

In the upper right corner, an angle is shown. In the enclosed example, the angle is 240°. That is the hue of any color that would lie anywhere on the yellow line seen in the example. As you can see, the yellow line crosses the letter G, which stands for green. So, the hue of any green pixel, from dark green to light green is 240°.

When used in effects, such as the "add hue" example above, Sony Vegas expresses this angle in values from 0.00 to 1.00. If you multiply that value by 360, you will convert it to degrees (Vegas, and many other editors, uses the values from 0 to 1 instead of 0 to 360 because it is more intuitive, especially for people who are not aware of hue being the angle on the color wheel). So, if you "add" 0.5 hue, Vegas will rotate the hue of every pixel by 0.5 * 360° = 180° (or, if you prefer, it turns the entire color wheel by 180°). That is a particularly interesting effect as all colors look like the "negative" but without the change in luminosity that exists in a true film negative. In an actual negative, light green turns into dark magenta. In the rotation by 180° light green turns into light magenta instead, as neither its luminosity (brightness, from dark to light) nor its saturation (color vs. black and white) is affected. In other words, the color of each pixel becomes its complementary color.

If you add 1.00 instead, Vegas will rotate the wheel by 1.00 * 360° = 360°, which means nothing will change (since turning a wheel by 360° just brings it back to its original position).

I hope this explains it. If not, keep asking. ;)

[Mike Kujbida]

Excellent explanation Adam.

For more help, here's a newsletter from Sony on Using the Vegas Pro color scopes

[Adam Stanislav]

Thanks, Mike. And thanks for the newsletter link.

[David Ruhland]

Adam... Do you think my comprehension of this topic is somewhat limited due to the fire water I used to drink when i lived in Harshaw? LOL

[Adam Stanislav]

Next time you come up to see the Hodag, stop by and we can go over it. :)

[D.J. Ammons]

The Vegas Pro 8 Companion DVD set by Gary Kleiner covers it. I think in the DVD titled "Image enhancement". I contacted Gary to see if he is going to come out with a DVD set for Pro 10 and he said yes. I will definitely get it. A lot of good tutorials out there but I particuarly like his because it is 12 DVD's so much more comprehensive than most. This DVD set and the VASST ones I own have been a lifesaver when we get stuck and can't figure something out.

[David Ruhland]

Originally Posted by Adam Stanislav

Might I suggest that instead of reading quick charts you study Chapter 8 (Color-Correction) of Digital Compositing for Film and Video, by Steve Wright.

Second or Third edition?

[Adam Stanislav]

Originally Posted by David Ruhland

Second or Third edition?

Third edition.

[Rochelle Morris]

So we have been so used to colour correcting our Z7 & GH1 footage and now that we have moved to 5D and a new TV, everything looks orange.

How can I reduce the orange most effectively? I use colour correct, levels + colour curves as base settings in process. I have just tried to reduce the mid tones as an experiment towards the blues...I have no idea if that's right or not.

All advice would be appreciated.