White Balancing Using A Card

ALO wrote on 9/5/2021, 9:17 PM

I have a few questions about white balancing using a card. Specifically, shooting a scene with a white card in frame, and then using something like Vegas' white balance plugin to white balance the scene by clicking on the card.

It looks like the card matters a lot. If you buy a generic white balance card on Amazon, you've apparently already lost -- at least according to Leeming's reviews:

https://www.leeminglutpro.com/whitebalance.html

So let's assume we've got a good accurate white card. I assume we want to white balance for the light falling on the scene, with as little reflected light falling on the card as possible. Ie, if shooting outdoors in daylight, you want the sun and the blue light from the atmosphere/sky on the card, but not, for example, the green light reflecting off the lawn you're standing on.

So it seems like maybe there is a bit of art to doing this well?

Am I getting the gist of this right? Any tips or pointers toward good resources much appreciated.

Comments

Musicvid wrote on 9/5/2021, 10:48 PM

Specifically, shooting a scene with a white card in frame, and then using something like Vegas' white balance plugin to white balance the scene by clicking on the card.

No, it's ideally about getting the white balance right in the camera, and not touching it in the editor. White balancing in post is actually destructive.

If you buy a generic white balance card on Amazon, you've apparently already lost -- at least according to Leeming's reviews:

Most are probably fine as long as they don't reflect UV. But read the reviews; cheap cards will sometimes make the video look pink.

So it seems like maybe there is a bit of art to doing this well?

Change the word "bit" to "lot."

 

RogerS wrote on 9/6/2021, 12:50 AM

You want the card to be a stand in for your subject so I would include reflections that would hit the subject when white balancing in camera.

Shoot a few seconds of the card, potentially while tweaking the angle slightly. If it doesn't look good this will help you with a reference in case you want to refine in post.

Do get a good card or you will have to compensate for it too!

Last changed by RogerS on 9/6/2021, 1:47 AM, changed a total of 1 times.

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Grazie wrote on 9/6/2021, 5:08 AM

Specifically, shooting a scene with a white card in frame, and then using something like Vegas' white balance plugin to white balance the scene by clicking on the card.

No, it's ideally about getting the white balance right in the camera, and not touching it in the editor. White balancing in post is actually destructive.

@Musicvid - Oh yes. This was the first my Video Mentor drummed into my head. It only took me twenty years to fully appreciate what he meant. I’m still not he really understood why, but there are you.

Grazie wrote on 9/6/2021, 5:15 AM

Mostly I’ve done WB for two adjacent Scenes where the WB was such a smack in the eye different or, it was just off enough that the green palour of the Bride was just too sickly to get me my invoice paid! Mixed lighting is the bane of Run n Gun Event OMBs or multiple cammies. Ugh…. Takes me back.

ALO wrote on 9/6/2021, 11:48 AM

No, it's ideally about getting the white balance right in the camera, and not touching it in the editor. White balancing in post is actually destructive.

I am specifically working with a camera that has no on-board wb capability, but noted -- thx.

RogerS wrote on 9/6/2021, 9:03 PM

What kind of camera has no on-board WB capability? GoPro? If so, here are some hints for optimal settings.

Former user wrote on 9/6/2021, 9:11 PM

 

No, it's ideally about getting the white balance right in the camera, and not touching it in the editor. White balancing in post is actually destructive.

@Musicvid - Oh yes. This was the first my Video Mentor drummed into my head. It only took me twenty years to fully appreciate what he meant. I’m still not he really understood why, but there are you.

I see the destructive nature when altering white balance and then trying to bring up shadow detail, The image falls apart much faster after adjusting white balance in editor

Musicvid wrote on 9/6/2021, 9:35 PM

The simple explanation is, all you can do is stretch the existing bits toward a chosen white point, which reduces bit depth. In extreme cases, this "falling apart" of a particular color could cause banding, such as the red in this example histogram.

@Grazie @Former user

Grazie wrote on 9/7/2021, 12:05 AM

@Musicvid - Of yes! LED Illumination can be see to have actual GAPS in the Wavelengths that then can’t be filled or adjusted for. I was shown this by placing a magenta filter over the Lamp. Nasty! Have LED Lamps been improved to combat these “gaps”?

RogerS wrote on 9/7/2021, 12:47 AM

@Musicvid - Of yes! LED Illumination can be see to have actual GAPS in the Wavelengths that then can’t be filled or adjusted for. I was shown this by placing a magenta filter over the Lamp. Nasty! Have LED Lamps been improved to combat these “gaps”?

Sure... for ones that are sold at premiums that are designed with color accuracy as a goal. It isn't as perfect a spectrum as the sun (or an incandescent lamp) but the low power usage, low heat and different form factors make them more usable for certain applications.

Howard-Vigorita wrote on 9/7/2021, 9:13 PM

The way white balance is supposed to be used is to determine the color temperature to set the camera to when you shoot. The appropriate card, white or grey, is totally dependent on the calibration of the measuring device you use. You need to read the device's manual to find that out. Given how expensive color temperature meters are, unless you're on a Hollywood budget, the measuring device is usually a camera. For instance, higher quality Canon cameras have on board color temperature measurement and their manuals say to use a white card. I've gotten great results using a white table cloth when I forgot mine. Other cameras specify neutral grey. Good luck finding a table cloth for that in a pinch.

If your camera doesn't have the ability to set white balance by color temperature, it might have rough settings like daylight, tungsten, florescent, etc. Just go by that. But I wouldn't recommend using a white or grey card read by Vegas or any other nle after the fact for color correction. Although it might be better than nothing, if you're lucky, best bet is to record a color chart. My x-rite color chart has both calibrated white and grey bands on the sides and they rarely work alone for me in any nle. But free Resolve has a great color chart mask & match function. And the ability to export a correction lut that you can pull back into Vegas. When the white balance is done before shooting, the correction curves and luts generated in Resolve do minimal tweaking if it was done right.

Grazie wrote on 9/7/2021, 11:03 PM

The way white balance is supposed to be used is to determine the color temperature to set the camera to when you shoot.

@Howard-Vigorita - Might I add to your comprehensive and "illuminating" experiences, that the purpose of that card or cloth or Bride's Dress is to provide a surface, with all ALL the various and mixed light falling on it, AT THAT POINT, and consequently the datum for the Camera to sit up and take notice, "Look Camera here, this is what I am calling White/Grey! Now, you senseless piece of kit, go away and adjust your settings accordingly!"