white balance & cards

Angelo

I've noted a few posts throughout the forums in which reference is made to white or gray cards and their use in establishing white balance...

Can anyone explain this or provide links to more information on how to use cards? Thanks.

Steve Cavigliano

Angelo wrote:

I've noted a few posts throughout the forums in which reference is made to white or gray cards and their use in establishing white balance...

Can anyone explain this or provide links to more information on how to use cards? Thanks.

Angelo,
I'd love to explain it to you, but I'd probably wind up confusing you. Read these links and it should come together. If not, ask away

http://www.photoxels.com/tutorial_white-balance.html

http://www.netwrite-publish.com/photo006.htm

http://www.cameraguild.com/technology/gray_card.htm

http://www.outbackphoto.com/workflow/wf_65/essay.html


Steve

Angelo

Steve Cavigliano wrote:

Angelo,
I'd love to explain it to you, but I'd probably wind up confusing you. Read these links and it should come together. If not, ask away

http://www.photoxels.com/tutorial_white-balance.html

http://www.netwrite-publish.com/photo006.htm

http://www.cameraguild.com/technology/gray_card.htm

http://www.outbackphoto.com/workflow/wf_65/essay.html


Steve

Thanks Steve. I will delve into these and hope to learn much.

DoctorIt

I found a very sweet card kit (almost like a keychain) from whibal.com. Nice small kit of gray cards, fits in your bag too.

trippy64

One of steve's links mentioned that they used these cards in SLR film? How did that work, or did I not read that correctly? I never shot film as much more than snapshots, point and shoot type stuff. i am just now deveoping an eye, and am trying to grasp all of this.

mercphoto

Angelo wrote:

I've noted a few posts throughout the forums in which reference is made to white or gray cards and their use in establishing white balance...

Can anyone explain this or provide links to more information on how to use cards? Thanks.

In a nutshell, if the light you are photographing under is not an equal mix of red, green and blue, like sunlight is, then you have a color shift in the image. Consider, for example, white sneakers in black light. We don't normally notice it because our eyes/brain compensate to a great degree. But that compensation doesn't work when we are seeing a print.

If you have a white card or a grey card, that reflects equal amounts of R, G and B, and then take a picture of it, if it is not in "white light" the camera will not record equal amounts of R, G and B. Next you tell the camera that this image is your custom white balance image. It uses the color shift it sees in this photo to determine what a custom white balance should be.

Someone asked why you would use a grey card for use in film. If you use an 18% grey card you can use that to determine your exposure setting. With film, it has nothing to do with white balance setting, it is used for exposure setting.

Steve Cavigliano

trippy64 wrote:

One of steve's links mentioned that they used these cards in SLR film? How did that work, or did I not read that correctly? I never shot film as much more than snapshots, point and shoot type stuff. i am just now deveoping an eye, and am trying to grasp all of this.

Trippy,
They were probably talking about using the gray card for setting exposure. Which you can also do with a digital. In a nutshell, a +/- 0 EV reading when metering off the gray card within the scene should get you the best exposure.

Steve

wxwax

mercphoto wrote:

In a nutshell, if the light you are photographing under is not an equal mix of red, green and blue, like sunlight is, then you have a color shift in the image. Consider, for example, white sneakers in black light. We don't normally notice it because our eyes/brain compensate to a great degree. But that compensation doesn't work when we are seeing a print.

If you have a white card or a grey card, that reflects equal amounts of R, G and B, and then take a picture of it, if it is not in "white light" the camera will not record equal amounts of R, G and B. Next you tell the camera that this image is your custom white balance image. It uses the color shift it sees in this photo to determine what a custom white balance should be.

Someone asked why you would use a grey card for use in film. If you use an 18% grey card you can use that to determine your exposure setting. With film, it has nothing to do with white balance setting, it is used for exposure setting.

Good stuff, esp. the film bit, I didn't know that.

Jekyll & Hyde

J: A good habit to get into is to include a grey card (as well as a color chart) in a test photo of the scene you are shooting. It'll give you a reference point when working in post, and also keep things consistent from shot to shot. I keep a variety of sizes around (I just cut them up), but I think I'll check out that link that Erik provided (looks like it'd be perfect for macro!).

H: I actually used a grey card quite a bit when shooting film, not only to set exposure, but also to provide a valuable color reference when printing (we didn't have the "eyedropper" tool back then, so I just included a grey card (and often color chart) in the test shot, and eyeballed it.

J: Kinda dates me, huh?

H: BTW, nice explanation Merc'.
J&H

pathfinder

Steve Cavigliano wrote:

Trippy,
They were probably talking about using the gray card for setting exposure. Which you can also do with a digital. In a nutshell, a +/- 0 EV reading when metering off the gray card within the scene should get you the best exposure.

Steve

Hi Trippy. Welcome back to dgrin.

That same 18% grey card used for exposure is an excellent source for white balancing in RAW converrsion also - It is actually better than a white card. I also use the Whibal.com set of cards - The studio set is about the size of a deck of cards. Fits in a bag nicely. Just include a sliver of the image of the card along the edge of the frame that will be cropped off in the final image after balancing in PS.

DavidTO

Just to make things even more confusing, don't forget warm balance cards!

wxwax

DavidTO wrote:

Just to make things even more confusing, don't forget warm balance cards!

Good one, David.

patch29

DoctorIt wrote:

I found a very sweet card kit (almost like a keychain) from whibal.com. Nice small kit of gray cards, fits in your bag too.

I finally saw this product last week. I was expecting them to be the thickness of formica and they were a lot thicker, maybe 3/16". It looked well made.

Personally I like the Gretag-Macbeth products. I have a big and small color checker chart and would like to pick up the new grey scale chart they make with white, grey and black, but it is definitely more delicate and needs to be better protected, and it does not fold together as the whitebal does.

lynnma

patch29 wrote:

I finally saw this product last week. I was expecting them to be the thickness of formica and they were a lot thicker, maybe 3/16". It looked well made.

Personally I like the Gretag-Macbeth products. I have a big and small color checker chart and would like to pick up the new grey scale chart they make with white, grey and black, but it is definitely more delicate and needs to be better protected, and it does not fold together as the whitebal does.

here's a challenge then for white balance... I cannot and I repeat cannot get the color right on this.. can you??? have a go at it...I'm done.. drove me nuts.

DavidTO

lynnma wrote:

here's a challenge then for white balance... I cannot and I repeat cannot get the color right on this.. can you??? have a go at it...I'm done.. drove me nuts.

Lynn,

Looks good to me. The challenge you're facing is that there are two color temperatures in the shot. There's the warm glow of the setting sun, and the snow is picking up the cool blue of the sky. But I think you did a fine job. You could check with Rutt, but I think it *looks* good.

bkriete

Is this more what you were thinking it should look like? I did a quick and dirty levels adjustment, than polygonally lassoed the area on the wheelbarrow that had the most different-looking light. I think I blew out some of your highlights...I definitely did not improve the picture.

Shay Stephens

Lynnma, you don't need to change the WB one bit on that photo. If you do, you will strip it of all life. This shows a wonderful and subtle mix of light. The cool tones reflected from the sky and th warm tones from the low angle sun. It is a wonderful mixture that breathes life into the shot.

A bad WB on this shot would have rendered on or the other colors away. If the WB were too cool, you would loose the warmth of the sun and vice versa. So don't do a thing to ruin the color, it looks perfect!

lynnma wrote:

here's a challenge then for white balance... I cannot and I repeat cannot get the color right on this.. can you??? have a go at it...I'm done.. drove me nuts.

lynnma

Shay Stephens wrote:

Lynnma, you don't need to change the WB one bit on that photo. If you do, you will strip it of all life. This shows a wonderful and subtle mix of light. The cool tones reflected from the sky and th warm tones from the low angle sun. It is a wonderful mixture that breathes life into the shot.

A bad WB on this shot would have rendered on or the other colors away. If the WB were too cool, you would loose the warmth of the sun and vice versa. So don't do a thing to ruin the color, it looks perfect!

OOOOOOOOOhhh thankyou so much.. how nice!!!! I was ready to have this shot torn apart cos I could'nt make it any better no matter what I did... obviously now I see that changing one wb would ruin the other.. thanks so much Shay and others for your kind words.

Sam

lynnma wrote:

OOOOOOOOOhhh thankyou so much.. how nice!!!! I was ready to have this shot torn apart cos I could'nt make it any better no matter what I did... obviously now I see that changing one wb would ruin the other.. thanks so much Shay and others for your kind words.

Lynn,

My first thought when I looked at your photo was, "Looks good to me". The problem "WE" have is that when working on our own photos we tend to look for perfection. We see and agonize over the leaves and loose site of the forest. if I am having trouble with a photo, I can sometimes put it away for a day and when I come back with fresh eyes it will come together.

Sam

pathfinder

I think Dave and Shay's comment nailed it. It is just fine.

I have noticed when I process RAW files of sunrise and sunset shots, that I have to be very careful using the white balance eye dropper, or the lovely warm tones disappear only to be replaced with cool blue ones. In the final analysis, the color has to be right to our eye, that is the final authority. :

Lovely shot Lynn. I love shooting snow scenes - everything looks so nice and clean and crisp.

BBones

so for me being out on the track shooting the races in the sun all day is shooting a white piece of paper at a 45 degree angle and setting that as my WB good enough?

Shay Stephens

That would give you a great WB.

BBones wrote:

so for me being out on the track shooting the races in the sun all day is shooting a white piece of paper at a 45 degree angle and setting that as my WB good enough?

BBones

Ok, last question on this, should I just set the cam to P mode or should I set it up to what I think I will be using for manual settings and then WB off that?

Shay Stephens wrote:

That would give you a great WB.

FreeUps

DavidTO wrote:

Just to make things even more confusing, don't forget warm balance cards!

David there is also the cheaper alternative to cards designed to swing your balance a certain way. You can either strap colored gels over your whitecard or IMO an awesome little tool which is a swatchbook. It has 400-500 different colored gels that come on a little keychain type mechanism. Works great for achieving any whitebalance out there. Dirt cheap from any expendable shop.