Setting White Balance

[jyrgen]

White piece of paper is not necessarily white, i.e. color neutral. There are very different "white" papers available. Maybe you have better luck using Kodak Grey Card or similar official/calibrated grey or white cards, that should be available in any well equipped photo store.

Secondly, why did you stated taking a picture under 6000K lights? You should take the reading of grey/white card under exactly the same lighting that you want to photograph your stuff. Which may be 6000K of course, but I just mentioned it to make sure you use it correctly.

[Roger_Cavanagh]

jyrgen is right. You must take the custom balance shot in the same lighting conditions that you want to balance.

Also it is the opposite of what you should do to over-expose the white target. This will blow one or more colour channels and throw the colour cast even further off.

It does not matter that you don't get white. What matters is that you get neutral. Using a gray card can be helpful because that reduces the chance of specular highlights/glare that would throw one or more channels off.

Of course, standard gray cards are manufactured for known reflectance not colour neutrality so you may still get a colour cast. The yellow cast in your pictures suggests too much blue in the white paper.

Regards,

[ejwebb]

So, Roger, what is recommended to set custom white balance if a grey card is not neutral? Is there such thing as a "white card" for this purpose? This is one of the things I was going to add to the wish list for Xmas but I am unsure what to ask for. Thanks.

[steven]

There are products out there that report to give you a "white ballance"

like

http://www.expodisc.com/products/expodisc/expodisc.html

[blinking8s]

i cant figure out how to measure the white balance on my 20d for some reason, i know how to set the desired temp in kelvin, but hell if i know how to measure what it should be on... i run a sony 570 at work and i understand everything about it...

i also have a white balance card

ie http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=300868&is=REG

[Roger_Cavanagh]

i cant figure out how to measure the white balance on my 20d for some reason, i know how to set the desired temp in kelvin, but hell if i know how to measure what it should be on...

Maybe this chart (http://www.rogercavanagh.com/helpinfo/31_colourtemp.stm) will help.

Regards,

[PhotosGuy]

The back of the Kodak gray card should be a neutral white.
Have you tried shooting RAW & fine tuning the correction in "color temperature"?

[PhotosGuy]

Are we talking about how it looks on your monitor? On the print?
I'm a bit at a loss here 'cause I don't have that problem with my 300D & I'm wondering if you might have a software problem. RAW should let you adjust the WB to a very fine degree.
I'm assuming that there is nothing in the original WB pic except the white paper, right? If true, & you underexpose the WB pic about a stop, you shouldn't be getting yellow results, so a software problem seems to be the only thing left.

[robertwgross]

Start from the beginning.

(1) What kind of camera are you using?
(2) Do you have any color tint parameters set in it?
(3) Are you trying to set a custom white balance in advance, or are you trying to correct a resulting white balance shift after the fact?

---Bob Gross---

[PhotosGuy]

Start from the beginning.

Good idea. It wouldn't hurt to post a representative pic along with the EXIF data, too.

[jhankins]

Takes a bit to get used to color management in the digital workflow. As you've discovered, it's a necessity to get this solved before they go out to print.

You have a number of things that need to be solved from capture to edit and output. Accurate color can be maintained through the process for sure so no worries there.

Some highlights of things I've found very helpful:

I set my Camera to Adobe 1998 color space (as this is my color space I've configured in Photoshop (I use CS).

I use a calibrated monitor (I happen to use Pantone's colorvision with Optical.) I recalibrate weekly. (I use a 23" Apple Cinema display which is wonderful by the way).

When I'm about to do a shoot, I'll take a shot in that lighting along wtih a GretagMacbeth colorchecker. (Really you can use their grey scale as what you need is an example for a neutral grey and sometimes black/white.

Now in photoshop I set the eyedropper settings to a 3x3 pixel sample.

I create an curves adjustment layer:

First: Double Click on the black eyedropper in the curves dialog

Set the Values for R G and B to 20

This will set a neutral value as well as ensure you still maintain some detail in the shadows

Now Double Click on the highlight eyedropper (the third)

set the values for RGB to 240 each

For Midtones set values to 128 each respectively

Save those settings as your default so you don't have to mess with them again.

Now you simply set the midpoint to your neutral grey target and optionally can also set your white and black points. (Which will typically darken and throw your contrast off) That's ok as you then can set your layer blending mode to color.

This sounds more difficult than it is. After you've set that first curve layer to reach the result you were looking for, which you can also fine tune after you'd done the above, you can drag and drop this adjustment layer on your other images that you've taken with that same lighting and adjust them that easily (you can also save the curves as a file and load it's settings as well (I use that often)

Best of all, all of the above were non-destructive edits on your images.

If you're working with RAW files, there are easy ways you can also adjust there and then apply that adjustment to a batch of raw files automatically. Also of course non-destructive and arguably faster without adding a layer.

For images that you've already shot without a target, you can use create a threshold adjustment layer temporarily and use to find your highlight and shadow areas, mark them using the color sampler tool (it's in the eyedropper flyout or use I until you get the target) You can have up to 4 of these per image, handy when you watch the info dialog by the way as the marked points will show up there and you can watch your adjustments numerically.

Post an image if you'd like and I can send a layered photoshop file back to you of it with the color cast removed.

(I'm assuming your exposing your white background to be white and that we're dealing with color cast not exposure)

by the way, I can attempt to capture a screen cam with audio narration of the above if that would be helpful. It might be easier to follow. I keep meaning to do that as this question is asked a lot.

Cheers!

Jim