Event White Balance in V4, Color Correction/Secondary Color Correction

wcoxe1 wrote on 2/1/2003, 9:40 PM
Someone, somewhere, mentioned that using V4's new Color Correction or Secondary Color Correction, you could do an event level, key-framable, even frame by frame, White Balance using the eye-droppers on something that was truly white in the clip.

The comment was made a while back when several people were asking for a feature that would automatically White Balance using some known true white object in a clip.

Any one know how? It isn't mentioned in the help that I can find.

Just for a trial, I took a digital photograph of a brand new, pristine paper photograph on Kodak RC paper, imported it into V4, and tried my darndest to get the white border edges of the photo to be truly white. Never was satisfied, not even close. Should have been easy. Tried every combination I could think of, starting over a couple of dozen times from scratch.

I am using a very nice, recently calabrated Sony 1354MD external monitor, so that wasn't the problem. I just could never get it really white either on the monitor, an attached camcorder screen, or a TV. Seems like it should be fairly simple, if I just understood the principle of the thing.

Tutorial, anyone?

Comments

Cheesehole wrote on 2/1/2003, 11:35 PM
I was able to do it by clicking the 'complimentary' eye dropper to the left of the 'High' color wheel, and then clicking the white area of an image. that should nuetralize the color so it is grey but it will probably look white. you might then apply 'color curves' and make an S curve to draw the grey-white area up to 100% white.

I did this using an image with clouds and a strip of beach. first I made the clouds white. then I tried it with the strip of beach. for that I had to use the High wheel (same as before, use the complimentary eyedropper), and then I set the 'Mid' wheel to the same settings as the high. using that setting with the color curve I was able to make the tan strip of beach turn white.

note: I'm using the normal Color Corrector for doing white balance, not the secondary color corrector, which is for affecting just specific colors.
SonyEPM wrote on 2/1/2003, 11:46 PM
Cheese has it right- you can rebalance low/mid/hi separately using the 3-wheel corrector and the complimentary eyedropper.
BillyBoy wrote on 2/2/2003, 10:26 AM
Just a bit of caution. Pure white (255) and pure black (000) rarely if ever appears in nature. So 'white clouds' for example or 'black pavement' really aren't that white or black, well almost maybe. So just be careful. Like I said a couple times already the color corrector tools in version 4 are much more powerful then in version three which were very good, this is kind of like that super size order of fries, you really get a lot. Don't ask how I know about super sized fries. <wink>
wcoxe1 wrote on 2/2/2003, 12:46 PM
I realize that white and black are almost non-existant, but there are plenty of nearlys. Good places to start. The white border edges of a brand new Kodak photograph may not be PURE white, but they are darned close. And, 255 was not what I was expecting, anywhy. Illegal color, remember?

The disappointment is that, after hearing and reading during the last 6 months about several recent packages what offer one-click White Balance, I was hoping that V4 with its fancy new CC and SCC would have something similar. Especially since I seem to remember someone saying it was there.

Maybe next time.
Tyler.Durden wrote on 2/2/2003, 1:29 PM
Hi William, all...

I think BillyBoy might be close and so might you. V4's CC is beyond "one-click" but very close. And white is a tough color because there isn't much color to assess.

The one-click concept is especially helpful for the improper white balance. This is typically a constant offset throughout the brightness range of the shot.

Working from that notion, I took a clip into the timeline and whacked it's color out using the color curves fx. I just moved the blue channel, in the same fashion a poor white balance would affect a shot - fairly consistant across the range.

Rather than using the hightlight complementary eyedropper on the white, I used the midtone comp.-dropper on what should be a grey tone - *pow* the shot was really close. Copying the values to the other wheels was even closer, and a slight reduction in magnitude was good enough for Govt. work.

So, it may not be "one-click", but it is easy to use and has so much more, that it seems a fine tradeoff in my book.

I'll keep trying with other footage; if it looks viable, I'll write it up as a tut.


HTH, MPH