White Balance Card

[Rohinton Mehta]

1) If we place a couple of white balance cards (from different manufacturers) side by side, we can notice that they all look slightly different. How can I be sure -- before buying one -- which white balance card is the correct one?

2) I have a many-years-old Kodak 18% grey card. Does one have to replace the card after certain number of years? I am unable to make out if the card that I have is still 'accurate'.

Thanks in advance.

 

[dabhand16]

I used to use grey cards a lot and trusted the ones I had as they were from decent suppliers. Had one in every bag but never compared them.

Now I carry a Colorchecker Passport as I'm a bit colour blind that has several WB and grey patches incorporated.

 

[bleirer]

All they need to be is neutral, even if a different shade of gray. As long as it is not so black that clipping is happening nor so white the whites are blown out. In rgb terms 118,118,118 is just as neutral as 150,150,150. So both would be a neutral target for white balance. Or anything darker or lighter as long as r and g and b are equal.

 

[Rohinton Mehta]

All they need to be is neutral, even if a different shade of gray. As long as it is not so black that clipping is happening nor so white the whites are blown out. In rgb terms 118,118,118 is just as neutral as 150,150,150. So both would be a neutral target for white balance. Or anything darker or lighter as long as r and g and b are equal.

Thanks, but is it possible to measure the RGB values on the grey card itself (to check if it is really neutral?)

 

[bleirer]

Thanks, but is it possible to measure the RGB values on the grey card itself (to check if it is really neutral?)

The maker of a quality card would calibrate it using their measuring equipment. Over time fading happens and we'd replace the card. We could illuminate the cards with neutral light if we could find out what the camera maker auto white balance considered neutral, maybe 4,500 or 5,000 Kelvin. Or take a shot in broad sunlight, which should be in the neutral range depending on where on the earth we are. We could hover over that card in lightroom and it should be pretty neutral in rgb values.

But remember that warm, cool, and neutral are perceptions that are relative to the other colors, so maybe we don't always want to have a measured neutral result. Sunrise for example we might want to lean warm.

 

[Archibald]

I'm wondering who actually uses gray cards when shooting portraits. Are they useful? Can they set your WB properly so you don't have to make further WB adjustments? My experience is that they are not much good, as color rendering of skin, makeup, background, etc vary too much.

 

[Nimi]

I'm wondering who actually uses gray cards when shooting portraits. Are they useful? Can they set your WB properly so you don't have to make further WB adjustments? My experience is that they are not much good, as color rendering of skin, makeup, background, etc vary too much.

Always. My studio lights are very stable and accurate, but I still start with the card being held by the sitter then again 30 minutes later once the lights are warmer. My edit starts with making sure the wb is correct using the dropper tool on LRC.

 

[bleirer]

The other thing that comes to mind talking about cards in general is that an 18% gray card intended for exposure is not necessarily guaranteed to be neutral as far as white balance, especially if they are cheap. So if one wants white balance use one for that purpose. I think a lot of folks here use the color checker passport, which has swatches for white balance for use with the eyedropper tool but also gray cards and standard color swatches and software to create a profile in lightroom for accurate colors. Fits in a pocket or camera bag easily.

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[Archibald]

Always. My studio lights are very stable and accurate, but I still start with the card being held by the sitter then again 30 minutes later once the lights are warmer. My edit starts with making sure the wb is correct using the dropper tool on LRC.

I understand that the grey card can help track varying color temperatures of the light, but that is not the issue I was thinking of. In my experience the rendering of colors is not always as expected and much diddling is needed afterwards because of that. Examples include makeup that renders greenish, or a black/neutral backdrop that goes violet.

 

[Nimi]

I understand that the grey card can help track varying color temperatures of the light, but that is not the issue I was thinking of. In my experience the rendering of colors is not always as expected and much diddling is needed afterwards because of that. Examples include makeup that renders greenish, or a black/neutral backdrop that goes violet.

The biggest difference I see in color variations is when switching among lenses on the same shoot due to the difference in lens design and sometimes lens chemistry and coatings. My Ai-S 135/2 is 300k warmer than my Z 85/1.2. For my workflow, and when I need to deliver a set of shots made with difference lenses, I need the skin tone to be the same, and the grey card does that for me. Never experienced really bad color cast due to makeup.

 

[bleirer]

I think there are several moving targets. One is the lightroom profile selected which influences the color. That's where the passport helps with its custom profile. The other is the white balance - if the light source is cool/bluish, say 6500K, when it illuminates the neutral gray card the gray card will have the same blue cast. When you use the eyedropper you are telling lightroom to warm that blue cast up to neutral. Maybe you don't want it totally neutral.

The other thing to consider when you get into the weeds is that the parts that are not illuminated by the main light might be partially lit by reflected light or fill lights, where if the light is neutral or slightly cool you might want the shadows to be slightly warm, or vice versa if the main light is balanced warm.

 

[PhilcTx]

1) If we place a couple of white balance cards (from different manufacturers) side by side, we can notice that they all look slightly different. How can I be sure -- before buying one -- which white balance card is the correct one?

2) I have a many-years-old Kodak 18% grey card. Does one have to replace the card after certain number of years? I am unable to make out if the card that I have is still 'accurate'.

Thanks in advance.

I wouldn't be concerned much about the differences other than a white card that is not shiny (i.e. matte finish) would be preferred. There are those that advocate using a plain piece of white paper - even wadded-up and kept in a pocket when not in use claiming that after smoothing out the wrinkled white paper it's surfaces are better for seeing the light coming from different directions/angles for more accurate results.

Grey cards are intended for exposure.

 

[dabhand16]

I'm wondering who actually uses gray cards when shooting portraits. Are they useful? Can they set your WB properly so you don't have to make further WB adjustments? My experience is that they are not much good, as color rendering of skin, makeup, background, etc vary too much.

Grey cards cannot give you a silver bullet 'one time' setting as light constantly changes outside.

I always used a grey card in the studio before I got my Colochecker Passport. The Colorchecker has several patches to WB on so you can fine tune too. In these controlled conditions one setting can be used until you change the lighting.

If you shoot portraits outdoors the WB can be affected by your environment. For instance if the Sun is out, then goes behind a cloud or if you are near or under trees you can get a green cast from the light reflected from the leaves. Best to shoot a grey card every time you move location or the light changes.

 

[dabhand16]

In my experience the rendering of colors is not always as expected and much diddling is needed afterwards because of that. Examples include makeup that renders greenish, or a black/neutral backdrop that goes violet.

Never had that happen. In what conditions were you shooting to get that happen, and did you use a grey card?

 

[Archibald]

Here's an example. SOOC. Her outfit is near-exact neutral, black background is purple, face (makeup I assume) is yellow-green.

You can only see EXIF info for this image if you are logged in.

 

[Nimi]

Here's an example. SOOC. Her outfit is near-exact neutral, black background is purple, face (makeup I assume) is yellow-green.

View attachment 96652

You're not on AWB, are you? Flash or continuous light, and have you checked the color balance of the light? Any ambient light? Agree, the colors are awful and very unlike-Canon which in my experience has the best skin colors.

 

[Archibald]

You're not on AWB, are you? Flash or continuous light, and have you checked the color balance of the light? Any ambient light? Agree, the colors are awful and very unlike-Canon which in my experience has the best skin colors.

I was using Godox flashes. Ambient was around 8 stops below the exposure. Shot in raw so the white balance is infinitely adjustable in post.

I've had this happen before and that's why I was doubting the usefulness of a gray/grey/white card.

 

[Nimi]

I was using Godox flashes. Ambient was around 8 stops below the exposure. Shot in raw so the white balance is infinitely adjustable in post.

I've had this happen before and that's why I was doubting the usefulness of a gray/grey/white card.

When you download a sequentual series, is there a shift in color between shots, or they're all like this?

 

[Archibald]

When you download a sequentual series, is there a shift in color between shots, or they're all like this?

They are all like this.

I think the cause is the color rendition of the background and also (but differently) the makeup. Both look different to the sensor than they do to the eye.

I've had more than one session like this, and that's why I thought it might be common. But apparently it's not.

My tentative conclusion was that cards are useless if one has to selectively correct colors.

 

[Nimi]

They are all like this.

I think the cause is the color rendition of the background and also (but differently) the makeup. Both look different to the sensor than they do to the eye.

I've had more than one session like this, and that's why I thought it might be common. But apparently it's not.

My tentative conclusion was that cards are useless if one has to selectively correct colors.

I reach the opposite conclusion; gray card may be the solition to your woes.

Are you shooting AWB, and if not, what's your color balance setting? Even when you shoot RAW, the camera records the white balance settings and imports it with the file as metadata. Depending on your RAW conversion software and settings, it may use that info to display the baseline photo.

Here is a typical simple workflow for studio work.

1. Set camera WB close to flash temp
2. Shoot a greycard as your first shot in a series
3. Import files
4. Use the eyedropper wb tool (in LRC) to adjust the white balance on the first shot
5. Tweak color balance until you're happy
6. Synch settings across the set, just white balance. This will give you consistent baseline you can now edit.
6. Proceed with edit.

Final note. I rented Godox for on-location shoot once and noticed that the color shifted as I changed power on them. I don't recall if they drifted with usage at constant power during the shoot, but it's not uncommon.

 

[Archibald]

When black isn't black. This was shot with one Godox light with softbox, without any ambient light. The objects all looked black to the eye.

You can only see EXIF info for this image if you are logged in.

I have had color shifts with other backdrops too, including white paper.

The WB setting was flash but is irrelevant because that setting doesn't affect the image data in the raw file.

 

[bleirer]

Can we see that same shot after you use the eyedropper on the gray card?

 

[Nimi]

When black isn't black. This was shot with one Godox light with softbox, without any ambient light. The objects all looked black to the eye.

View attachment 96659

I have had color shifts with other backdrops too, including white paper.

The WB setting was flash but is irrelevant because that setting doesn't affect the image data in the raw file.

I'll try one last time, then I give up.

Shooting RAW allows you to adjust the image, but RAW is not the displayed image, but some conversion depending on your editor setting. The white balance is recorded when you shoot, and might be used to display the image, in your case poorly. A grey card and knowing how to use it can reset the color balance of the displayed image to truer, more natural and consistent color.

 

[Archibald]

With the eyedropper on the textured backdrop, I get this:

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[PhilcTx]

Are you using a white card to set a custom white balance? If so - still getting color shift?