Using the Color Corrector plugin:

Have you tried taking the Choose Complimentary Color eyedropper from the High color wheel on the right and clicking on something white (preferrably clothing) in the video in the preview window and then doing the same with black using the Low color wheel on the left?

John

email me a screen grab or two to

"d a v e {At} d a y - v i d s p r o d u c t i o n s . c o m"

(remove the spaces and switch that {At} to @ from that email, and I'll be happy to see what I can do, if I can pull it off, I'll give you a short tute on how to do it.

Dave

try the easy method I outline in this thread

2- From what I can figure out about the underlying math/algorithms:

When you set white balance in camera, the camera adjusts the red green blue gain controls (gain = multiply).

Vegas' color corrector actually doesn't do the opposite of that. It does operations in Y'CbCr color space, which is wacky IMO. The method B outlined in my other post will adjust the gains to do what a camera will do. However, it doesn't work perfectly because...

(this is just my guess here) In each of the r/g/b channels, the transfer response becomes non-linear as you get into the extremes. That is, you get color shifting (especially as you hit the highlights of that channel).
When you change the gains on each channel *in post*, you actually have to increase the overall gain. I think this makes any non-linearities more obvious, since it effectively increases saturation.
Doing so also throws away dynamic range (because you really do want to clip some information) and increases your noise.

Anyways, just try the 3-way color correction + the secondary CC.

Glenn,

How about using After Effects Pro/Combustion etc. to do the color correction in 16-bit or float format, then convert the result to 8-bit?

I don't think that would really help much.

No matter what you do, it will never look as good as if you taped it properly to begin with. Maybe you could go with an artsy approach, and make this portion black and white.

Glenn,

Wouldn't that be more like having it done in-camera (where it is done with more bits)?

The main problem is that when you adjust the gains in post, 1 or 2 of the channels will go above normal range. Suppose the B and G channels go over. You don't have the corresponding R channel information. The easiest way to fix this is to clip the B and G channels.

Or if you use the secondary color corrector method (de-saturate the highlights), you are kind of "filling in" that missing highlight information.

2- I believe this is correct, since I've tested this. The non-linearities in all cameras (they rarely track grayscale perfectly) throws things off though.

3- If you process things in post at a higher bit depth, then you avoid some of the quantization error that can happen.

you could always Sepia the whole thing plus some hazyness and popo you get a rich, artistic effect and no color correction problem .......

"I guess my first question is philosophical.... Is it possible, given infinite intelligence and a black belt in the use of Vegas color corrector tools, to correct a horribly white balanced clip such that it looks precisely as it would had the camera been set correctly? Or is there simply something inherent in the video once it's shot incorrectly that it'll never look perfect? "

Not perfect... but sometimes, if i have a shooter who forgets (it happens) they jsut keep shooting and when teh EVF is BW, theres no way of telling...

either way, i run a series of corections and levels chains to create an oversaturated master.. it actually looks ok once you crank everythng, it has teh look of "E6 crosprocessing" but then i bring it back in and tweak a little more..
it wont ever be as perfect as it should be, but thats life in teh events game...

Just a thought here, I haven't tried this but here goes.

Wouldn't color curves be a better tool than the usual color correction toolset? Reducing the gain in the red channel rather than increasing the gain in G and B channels would avoid the clipping problem. Also curves could be shaped to compensate for the non linearity issues.

I'm kind of curious about all the implications of this.
Most of the prosummer cameras appear to adjust white balance by controlling gain in the RGB channels. Higher end cameras seem to use optical filters, they have a knob near the lens mount for ND and CT adjustments which seems to rotate a filter wheel. This might be the 'best' approach, get the light close to correct and then the amount of gain needed per channel is kept within tighter limits hence minimising noise issues.

Bob.

what i usualy do is run a colour balance and kill off the highlights blue tone.. then add a colour corrector to bring in the other RG which is missing...

Now this additional colour ads luminance but u can also supress the luminance by using colour balance instead of colour corrector (jsut tick the checkbox for it.. )

I try not to mess with gain or gamma, as u end up losing imagine info, but once i sort out teh colour issue, i then place a levels filter BEFORE everything.. i add it later, but then its placed in front of teh chain.. and its here than i adjust the luminance before any of the colouring is tweaked...

Working this way helps create a base colour fix, then adding the levels afterwards allows that colour to be tweaked again AFTER u sort out the exposure...

2G? Do you use Copy To Clipboard, and then bring this BACK into the Preview so you can "compare" that which you WANT against that which HAVE? Meaning, using a "good" Event as your key to changing the Event that needs "correcting"?

If you have, apologies - if not, this makes life very easy indeed.

At the end of the day, what I do, is to then sit back and look at the total Video; the areas that have been worked over and "changed"; where the action falls into place for the colourization and maybe use a gradual change of colourization over those "iffy" sections.

.. oh, and ALWAYS, if have it, use an external monitor to do CC work! I don;t know WHAT I'm gonna do when CRTs are finally laid to rest and we completely enter the digital world of colourization. Hopefully I will be long gone.

There is a plugin for NewTek's VTEdit called BobsOneTouch. It performs a one-click white balance. You simply click on an area that is supposed to be white. I have not used it myself but VT users seem quite happy with the result. You may want to find a VT user in your area and let him try it on a sample of your footage.

I'm not sure if this plugin is doing something similar to using the complimentary colour picker in Vegas CC as suggested by craftech. If it is, it's probably doing it across all levels, not just highs, mids or lows.

Here's a link to Bob Tasa's online demo.

http://www.toastergarage.com/bobfx/IntroBobsOneTouch.html

theres a free mike crash plug from virtualdub, its called autolevels, BUT it doesnt lock WB... so u get fluctuations.. this si the only thing holding me back from using it on all CC work..

Here's a white balance trick that works great in Vegas using the waveform monitor and vectorscope. I've used this method for years from way back in the analog days...

Find a scene with something that is supposed to be white (but isn't.) Place the full-up color corrector filter (not the "simple" one) on the clip in question. Select "video scopes" under the VIEW menu. Select the waveform monitor and place it in the "composite" mode. Notice where the object that is supposed to be white appears in the waveform monitor, it should be somewhere near the top of the scale.

Using the "high" color wheel in the Color Corrector dialog box, move the marker around until the area on the waveform monitor that is displaying the white object "nulls out." In other words, where that horizontal portion of the white object on the waveform monitor becomes the "thinnest." You'll see what I'm talking about when you do it.

You can also set the black balance using the vectorscope. Select a portion of the clip that has the most blacks, or near blacks, in it. Select the vectorscope and select "magnified" (where it usually says, "normal") Now using the low color wheel, move the marker around until the fattest portion of the "blob" is centered in the vectorscope window.

You can play with the "mid" wheel and set it to suit you taste, or perhaps just not touch it at all. Now, go back to the waveform monitor and select "luminance", find the brighest section of the clip and then adjust the "gain" control in the color corrector filter until the white object sits at "100%" and you're all set. If there are some black portions in the clip, then adjust the "offset" in the filter until they display just above "0". Do this BEFORE you adjust the gain of the white object to 100%.

Of course, use a calibrated video monitor to make any final decisions about color correction adjustments.

John

John...


thanx, so much, for this. i've been doing a similar thing by eye, without the scopes. this works great!! thanx for the tip.

John! A BIG thank you from me too!

I've been using the Complimentary eye-dropper on the 3 wheels to set adjustment and then use the Waveform to get less than 100 "levels" then readjust the black set up, Gamma and saturation and that works well, but your additional tips make for working with CC even more accurate and flexible.

One difficulty with this method is you mightn't have a frame with a large slab of white, use cookie cutter or bezier to window the scopes.

Bob.

Several times I've suggested to Sony that a future version of Vegas include a plug-in with an eyedropper ala Photoshop (even Elements) for white balance. Even Magix Movie Studio or whatever it's called has that feature.

In fact, I imagine you could also capture a frame and open it in Photoshop as a jpeg, use the white-balance eyedropper feature and read RGB numerical settings in that frame grab, then switch back to Vegas and enter the same values.

Wouldn't color curves be a better tool than the usual color correction toolset? Reducing the gain in the red channel rather than increasing the gain in G and B channels would avoid the clipping problem.
You actually *do* want to clip information. Otherwise values that are originally white (i.e. blown out), will pick up a color cast once you adjust the r/g/b gains.

As far as the non-linearities go... I haven't figured out an easy way to figure them out.

Most of the prosummer cameras appear to adjust white balance by controlling gain in the RGB channels. Higher end cameras seem to use optical filters, they have a knob near the lens mount for ND and CT adjustments which seems to rotate a filter wheel. This might be the 'best' approach, get the light close to correct and then the amount of gain needed per channel is kept within tighter limits hence minimising noise issues.
Yep, that's what I believe they're for. I think filter wheels would be more useful on the digital cinema cameras, as it would buy you additional dynamic range. There's lots of discussion about this on the CML... the Viper camera doesn't have a filter wheel with magenta filters built in.

Several times I've suggested to Sony that a future version of Vegas include a plug-in with an eyedropper ala Photoshop (even Elements) for white balance. Even Magix Movie Studio or whatever it's called has that feature.
The 3-way CC is Vegas' version of that.

However, a better algorithm (IMO) is to adjust the RGB gains and have intentional clipping of particular channels. It also lends itself to a one-click operation, and avoids discolored highlights issues (that you have with the 3-way CC).

2- The gradient map filter can be disabled and you can use its eyedropper to get RGB values.
Or use the utility TakeColor. Takecolor only samples a single pixel, which is prone to noise (as opposed to drag selecting an area).

You actually *do* want to clip information. Otherwise values that are originally white (i.e. blown out), will pick up a color cast once you adjust the r/g/b gains.
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I think here is the nub of the problem.
With the color balance this far off what's going to happen I think is that colors at say the red end are going to clip to white before they should. Now trying to correct that is impossible, the actual data that'll tell you what color it was got lost when it got clipped.