How to use a Gray Card

[JeannieK]

What is the correct way to use a gray card? I place the gray card in the frame of the photo to be taken? Then what?

[teaking]

You photograph it in with the picture or set of pictures your taking. If its constant light you can photograph it in one shot and batch process. The idea is you know what colour it should be so when editing you can set a sample point on the grey card and change its colour or use it as a grey/white point with Layers/Curves adjustments. So by correcting this colour you correct the overall colour of the image and get the correct white balance.

Or thats at least thats how I understand it... never used one haha so hopefuly someone will correct me.

[zona5101]

Originally Posted by teaking

You photograph it in with the picture or set of pictures your taking. If its constant light you can photograph it in one shot and batch process. The idea is you know what colour it should be so when editing you can set a sample point on the grey card and change its colour or use it as a grey/white point with Layers/Curves adjustments. So by correcting this colour you correct the overall colour of the image and get the correct white balance.

Or thats at least thats how I understand it... never used one haha so hopefuly someone will correct me.

This is correct - a gray card can be used to help set the white balance in post or to create a custome WB in camera. You can also use it to help you with difficult metering situations. Your camera meter reads reflected light and 'sees' everything as 18% gray. Some surfaces may fool your meter by being more or less reflective. Using a gray card you would eliminate those abberations and give you a more consistand reading of the average light falling on the subject.

With the sophisticated meters in most cameras, i would say if anybody is using a gray card nowdays it is for white balance...

[SusanH1970]

Rather than adjusting my WB in post, I fill the frame with the grey card and take a shot of it, then set CWB in-camera. If my lighting changes, I have to do this again (and keep doing it if the light continually changes, as it does in an outdoor shoot most of the time). For studio I just have to do it once and I'm good to go.

[ffscj3562130]

Is using a gray card and a white card of equal value in setting a custom white balance or is one better than the other?

[zona5101]

Originally Posted by ffscj3562130

Is using a gray card and a white card of equal value in setting a custom white balance or is one better than the other?

either one will work. you shouldn't have to make any distinction when using one or the other when setting a custom white balance in your camera. Double check your manual but that is my understanding of Nikon custom WB.

[ffscj3562130]

Thanks Zona.

[GadgetRick]

Originally Posted by ffscj3562130

Is using a gray card and a white card of equal value in setting a custom white balance or is one better than the other?

Depends on the camera. Most cameras today do better with a gray card (my understanding anyway). Some older models do better with a white card.

[Swisstony10]

I use my grey card to set a custom white balance for a given situation, so it's one thing I don't have to tweak in post. If I have to move quickly to a different setting to take some shots, and don't have time to set a new custom white balance first, I do a shot of the grey card at the end, and then use that to set a new white balance and apply that as a batch process afterwards.

I prefer to set the custom white balance first, but it's not always possible.

[spazoid1965]

I use a white card for custom white balance. When I had a grey card I used it to get an exposure reading from. Now that I can't find my grey card, I use a grocery bag from my local grocery store. It will usually under expose the shot by 1/2 stop. But it is very reliable and easy to compensate. Even if it does seem a little odd to some people.