Grey Card Sets = What are the Other Two Cards For ???

I have watched dozens of videos on how to use a grey card (some say they are to set White Balance and others swear that this is wrong); and, many times, a grey card will come in a set with a white and black card.

I have never read nor seen anyone mention the other two cards; what are the black and the white card for ?


Thanks for reading and all help is appreciated.

The white card is used instead of the gray card in low light situations.
Kodak didn't give me a black card way back when, so you'll have to wait for someone else to answer. I might use it to set a black point in PS.

I've always used white for WB, grey for exposure, and have never needed a black card. White can be used for exposure, but it will give you a false underexposure. Grey can be used for WB, but if you've got a white card...

PhotosGuy wrote in post #18886111
The white card is used instead of the gray card in low light situations.

PentaxShooter wrote in post #18886206
I've always used white for WB, grey for exposure.

Thanks to you both.

1. Are you guys using an in-camera custom WB, or doing it in post, or both ?

2. In post, it is my understanding that, if your program has three color-pickers, one should use the picker that coincides with the color of card used; however, some programs only have a single picker/sampler; in such a program, for correcting/setting WB, I am guessing the white card would be preferable to the grey ?

3. I am often shooting outdoors, most likely in an open field, between 9:AM and 3:PM, with the sun beating down or partially cloudy. I will be moving from subject to subject, taking shots from all four sides; hand-held and "point-n-shoot."
In such conditions, can I set WB once and that be okay for all of my shots (considering the overall lighting remains the same); or, would I be better off just letting the camera decide and hope for the best ?


>>> On EDIT: Subjects usually are trains, and antique/classic tractor and engine shows.

If I bother to use a WB card, I use C.WB. I've seen some photographers shoot a raw file of the white card, then use that to make WB adjustments in post. If you've already got the info in the camera, why bother working in post? I've had really good luck adjusting WB in LR6 with the eye-dropper, but if I've set a C.WB, there is no need to work WB in post.

I shoot more film than digital. Shooting a WB card makes a lot of sense when shooting film (it is much easier than working with filters, and more accurate than guessing), until you start to run into the $2.50 - $3.00 per shot film and processing costs. If you need it, you need it.

Put all three cards in a shot, with the exposure as determined by the grey card, and the shot will have a histogram with peaks at black, at 18% grey, and at white...

1. the gray card, of course helps to set fundamental exposure setting
   
2. but both gray and white allows you to readily determine precisely how much/little to adjust (the exposure suggested by the meter) for purposes of practicing ETTR without the white falling off the histogram
   
3. and with black and gray and white it can be very handy for determining multiple adjustments during postprocessing the shots taken in that lighting situation
   
4. and if the grey card covers the central 1/3 of the Canon frame, while the white portion is in the outer 1/3 of the frame, that shot can do both expossure determination and ETTR and custom white balance in s SINGLE SHOT.
   and if the black card is in the other 1/3 of the shot, you can do both #1 and #2 in a single shot
   

Wilt wrote in post #18886327
Put all three cards in a shot, with the exposure as determined by the grey card, and the shot will have a histogram with peaks at black, at 18% grey, and at white...

1. the gray card, of course helps to set fundamental exposure setting
   
2. but both gray and white allows you to readily determine precisely how much/little to adjust (the exposure suggested by the meter) for purposes of practicing ETTR without the white falling off the histogram
   
3. and with black and gray and white it can be very handy for determining multiple adjustments during postprocessing the shots taken in that lighting situation
   
4. and if the grey card covers the central 1/3 of the Canon frame, while the white portion is in the outer 1/3 of the frame, that shot can do both expossure determination and ETTR and custom white balance in s SINGLE SHOT.
   and if the black card is in the other 1/3 of the shot, you can do both #1 and #2 in a single shot
   

If you have the white and they grey card in the shot, it is possible to determine the numerical values of the lighting contrast ratio in that situation.

Thanks !

What dimensions/size cards are recommended to accomplish these feats ?

What I have now are three little 2-1/8 x 3-3/8 cards on a neck-strap.
I was just outside, playing around with them.
To fill the frame with one of them, I have to zoom out there (250mm) and the card is still awfully close to the lens. (hand-held...the card that is)

I can see how these small cards are okay for placing in the shot for sampling in post; but, I would imagine larger cards would be necessary for setting exposure and C-WB ?

Considering your #4 above, must the orientation/placement of the cards fill the frame; or, can the scene be partially visible ?

What dimensions/size cards are recommended to accomplish these feats ?
Photovision makes targets that put all three tones (black, 18% midtone, white) on a single fold-up target, and they come in about 3 or 4 sizes (one shown in Adorama ad)
https://www.adorama.co​m …PAOO5JxSgn7AaAk​k0EALw_wcB
...you simply fill the frame with all three zones, and the center conveniently covers the central third which is what the Canon needs for Custom White Balance. I have one 14" and generally do not feel impeded at that size.


What I have now are three little 2-1/8 x 3-3/8 cards on a neck-strap.
I was just outside, playing around with them.
To fill the frame with one of them, I have to zoom out there (250mm) and the card is still awfully close to the lens. (hand-held...the card that is)

I can see how these small cards are okay for placing in the shot for sampling in post; but, I would imagine larger cards would be necessary for setting exposure and C-WB ?

Considering your #4 above, must the orientation/placement of the cards fill the frame; or, can the scene be partially visible ?[/QUOTE]
the center 1/3 of the frame has to be filled with your white balance target in order to Custom White Balance.
OTOH, I often do not bother with CWB, but simply shoot RAW and fix it during postprocessing!

The post-processing fix is probably quickest/easiest/best in the long run; but, I like to also know as much as I can about all the options.

Thanks for pointing me toward the Photovision targets.

Just thought I'd share an example shot of the Photovision target in a scene,

BuckSkin wrote in post #18886219
Thanks to you both.

1. Are you guys using an in-camera custom WB, or doing it in post, or both ?

2. In post, it is my understanding that, if your program has three color-pickers, one should use the picker that coincides with the color of card used; however, some programs only have a single picker/sampler; in such a program, for correcting/setting WB, I am guessing the white card would be preferable to the grey ?

3. I am often shooting outdoors, most likely in an open field, between 9:AM and 3:PM, with the sun beating down or partially cloudy. I will be moving from subject to subject, taking shots from all four sides; hand-held and "point-n-shoot."
In such conditions, can I set WB once and that be okay for all of my shots (considering the overall lighting remains the same); or, would I be better off just letting the camera decide and hope for the best ?

>>> On EDIT: Subjects usually are trains, and antique/classic tractor and engine shows.

Good answers above, but just to clarify how I do it...
1. First of all, 99.99% of the time I shoot in RAW. CWB always where I have time for a studio shot. Outdoors generally I use a pre-set because what I want is consistency. Consider that the "correct" WB for a particular shot may not be the "right" WB for that particular image & I may tweak the image in PP to what is pleasing to me.

2. If you let the camera choose the exposure just for WB, all 3 cards will photograph as gray & will work for WB.
Re: "The white card is used instead of the gray card in low light situations." You do know if you do that, you'll have to compensate for the fact that it's not gray, right? So you're going to have to figure out how much to open up from the white card "suggested" exposure.

3. If there's time, I NEVER let the camera decide. I would rather shoot on the wrong WB first because it would be consistent for PP than have the WB be all over the place. This is why I shoot in RAW.

And FWIW, I don't carry a card with me. RAW gives me a lot of latitude & I want to concentrate on the image & not fiddle around with things that I can tweak in PP. So generally, 99% of the time I use manual NOT including Auto ISO, & suggest that you read this for an alternative way to set exposure: : Need an exposure crutch?

PhotosGuy wrote in post #18886653
Good answers above, but just to clarify how I do it...
1. First of all, 99.99% of the time I shoot in RAW. CWB always where I have time for a studio shot. Outdoors generally I use a pre-set because what I want is consistency. Consider that the "correct" WB for a particular shot may not be the "right" WB for that particular image & I may tweak the image in PP to what is pleasing to me.

2. If you let the camera choose the exposure just for WB, all 3 cards will photograph as gray & will work for WB.
Re: "The white card is used instead of the gray card in low light situations." You do know if you do that, you'll have to compensate for the fact that it's not gray, right? So you're going to have to figure out how much to open up from the white card "suggested" exposure.

3. If there's time, I NEVER let the camera decide. I would rather shoot on the wrong WB first because it would be consistent for PP than have the WB be all over the place. This is why I shoot in RAW.

And FWIW, I don't carry a card with me. RAW gives me a lot of latitude & I want to concentrate on the image & not fiddle around with things that I can tweak in PP. So generally, 99% of the time I use manual NOT including Auto ISO, & suggest that you read this for an alternative way to set exposure: : Need an exposure crutch?

^^^ 110%
I often do not carry my Photovision with me for events, but it goes with me especially when I know I have a client who is particularly picky about color accuracy and I am trying to maintain 'studio lighting' conditions during the shoot!