Grey card for custom white balance?? Although the manuals for every camera I have says to use something white for setting a custom white balance, I have also read/seen videos that say...

Rab-Eye Loc: Indiana

Although the manuals for every camera I have says to use something white for setting a custom white balance, I have also read/seen videos that say to use something white or a gray card. This makes no sense to me (they are not talking about using the grey card as a reference for setting WB in post). How can telling your camera that a grey card should be white result in correct WB? Are these sources simply wrong, or am I missing something?

Thanks!

bleirer

For white balance anything with equal r, g, and b will work. So middle grey might show up as 118, 118,118 if you hover over it, but light grey might be 211,211,211. The problem is grey cards for exposure might have a tint and not be true grey cards. One sold for white balance might be closer to neutral.

Its pricey but the color checker passport photo is tested for the grey patches they give to be reliably grey or white or whatever neutral. Adding to its cost is other standard color patches and the software it comes with to calibrate camera color, so I'm sure there must be lower cost cards if all you want it for is white balance.

The reason grey is used is white can get oversaturated especially if light is bright then you don't get reliable results.

rook2c4 Loc: Philadelphia, PA USA

As long as the gray card is neutral gray, it will be just as effective as a white card. Neutral is the key here.

joecichjr Loc: Chicago S. Suburbs, Illinois, USA

I learn something whenever I'm here⭐

bsprague Loc: Lacey, WA, USA

Grey cards are a holdover from when meters, especially internal 35mm camera meters, were relatively new. They are colorless for the white balance and reflect 18 percent of the light. That is roughly equal to what is an average reflection for an average scene on an average day. Kodak made good ones that were pure white on the back side.

With films like Kodachrome it saved a lot of money to get the first shot right. With digital it is so easy to bracket and adjust WB in post that I don't carry a gray card any more.

PHRubin Loc: Nashville TN USA

White balance is for tint, not exposure. Both white and gray are neutral in tint.

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Rab-Eye wrote:

Although the manuals for every camera I have says to use something white for setting a custom white balance, I have also read/seen videos that say to use something white or a gray card. This makes no sense to me (they are not talking about using the grey card as a reference for setting WB in post). How can telling your camera that a grey card should be white result in correct WB? Are these sources simply wrong, or am I missing something?

Thanks!

Depending on whether you’re the glass half full or half empty type, grey is just a darker shade of white or white is just a brighter shade of grey. They are the same color. A grey card in bright sun is the same as a white card in the cellar. If you’re losing sleep over it, get a double sided card with both shades on it.

Strodav Loc: Houston, Tx

I shoot raw and often take a shot of a 3 square gray scale with white, mid gray, and dark gray squares (QPCARD 101 from Adorama). The white and dark squares can help set exposure while shooting and the mid gray can help set white point during PP. It's basically a reference so you can compare what you see on your monitor during Post to the reference. Years ago I was taught to take a picture of the palm of my hand to act as a reference if I forgot my gray card, so many different kinds of references work. But you need to be a bit careful how you use it. What if you were shooting during the golden hours? What happens during Post if I were to try and make the imaged gray patch on my monitor match my gray reference under the 5000k lights I use in my lightroom? Sometimes you want a color cast and don't want to remove it like during the golden hours or the warmth you get from a candle or incandescent bulb.

bleirer

Strodav wrote:

I shoot raw and often take a shot of a 3 square gr... (show quote)

Thats another cool feature of the passport i mentioned earlier- it has white balance patches with various amounts of warming or cooling in case you want to set it in camera or don't trust your own eye in post. For example warming up skin tones or cooling a landscape.

Rab-Eye Loc: Indiana

PHRubin wrote:

White balance is for tint, not exposure. Both white and gray are neutral in tint.

I do understand the difference between white balance and exposure, but it does seem counterintuitive that gray and white are both neutral in tint.

PHRubin Loc: Nashville TN USA

Rab-Eye wrote:

I do understand the difference between white balance and exposure, but it does seem counterintuitive that gray and white are both neutral in tint.

While they have different AMOUNTS of r,g,b, they have them in the same proportions. If the proportions were different there would be a hint of the component (color) in higher proportions.

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Rab-Eye wrote:

I do understand the difference between white balance and exposure, but it does seem counterintuitive that gray and white are both neutral in tint.

Well, just what does your intuition say ?

A satisfactory result when art and tech meet is often the combined influence of absolute metrics and artists’ intuition.

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A bit of evidence of such a meeting is cameras with two versions of Auto WB, having both “normal” AWB and an AWB annotated with “Ambi” or “Warm”. The latter being an attempt to avoid fully “normalize” the WB of scenes that the system detects as “tinted but normal”. Only an AI version of artists’ intuition, but imitation is flattery.

Rab-Eye Loc: Indiana

PHRubin wrote:

While they have different AMOUNTS of r,g,b, they have them in the same proportions. If the proportions were different there would be a hint of the component (color) in higher proportions.

That is really interesting. Thank you so much for explaining. I also want to thank everyone else who contributed to the thread. It was definitely educational for me.

SteveR Loc: Michigan

I used a piece of white printer paper when setting the balance for my flash. The colors came out fine.

Pablo8 Loc: Nottingham UK.

I did use my 10"x 8" Kodak grey cards for a number of years (Pre Digital Days). They became rather scuffed/marked. so along came a Plastic Exposure disc, 5" diameter Grey one side , and white on the other. A fine pattern on both sides, if one needed to check/ pre set focus. No manufacturers name , but "Full Colour Balance Disc" is marked around the edge of the disc.. Have used the disc from APS frame up to 5 x 4 neg size set ups. If one includes it within a sample shot, the grey, or white side can be read with PS or whatever editing programme one uses. If this reads as neutral (Equal amounts of red/green/blue ) then a good colour balance will be assured. If you do NOT want a neutral balance, then don't bother using a Grey/White card reading. Just "Stick your finger in the air and guess", if it pleases you.