Which eyedropper for colour balance?

a better choice is shooting raw and using the white balance eye dropper on a tone you know is a neutral shade 9meaning you knowthat there are equal or very close to equal amounts of Red , Green and Blue values in that gray tone.

It depends on the image. This tutorial will show a technique that explains why white balance can be a tricky situation image by image...

Bruce Fraser's White Balance through Auto Color

Scans may require one way while digicams require another due to different lighting characteristics and how they influence midtone colors derived from the varied color tables produced by each capture device and scene.

For instance hot red looks oversaturated shot under warm lighting, but when you try to neutralize this warm cast hot red turns dull red because of an increase in the blue channel and decrease in red. Blend modes like Color, Saturation or Luminance can do a lot in controlling this.

There are so many ways to approach this. I shot a series of flowers recently under the same digicam WB setting that turned out a bit dark. I found a simple move of the highlite slider in Levels to the left caused the vibrantly peach colored flower to lose richness and turn a bit pinkish because the blue channel gained in the mids for some reason.

To control this I sampled a white object whose WB RGB combo was 230,220,200 in the Color Picker. Clicked on the Lab Luminance radio button and increased this RGB combo as light as it would go before it changed hue (around 250,240,210) and established that as my highlite setting.

Exited Color Picker and clicked the highlite eyedropper on this same whitish area which brightened the entire image without affecting color and vibrancy of the flower. A regular Luminance blend mode approach would add a blackish, kind of desaturated tint to my results but not change the hue of the flower. The Bruce Fraser Auto Color technique tutorial got me to thinking and altering my approach to WB adjust in this manner.

Or maybe it just made me too picky about color correction. Not sure.

If you're working on dslr raws: Adobe Camera Raw has a dedicated "white balance" eye dropper. I found it quite effective coupled with having a grey card in one shot.

I use a method taught to me by charlie cramer. I go into curves, click on white dropper, select a white point, look at L, a, b., I zero out the a and b values, next hit ok, then i go back and select the white point. If I don't get exactly what I want i change the opacity in that level. At the end it will ask if you want to save your settings. I always mark no.

For gray balance I just select a number of mid tones until I get close to what I want and then adjust opacity in that level.

sorry when I said I change the opacity in that level, I meant layer. I always just work in curves.

I've been doing this, maybe its not best,but the results seem ok. Assuming its not a raw file, I take the file in CS2 use the color picker, make the info tab visible (default next to navigator, pick a neutral gray, often using the street or something and then balance the values so the rbg values at that selected point are the same, than I know that's a gray. I can then set levels to bring it up or down. I'm finding this often cures any color casts I may have out of camera. but I'm interseted in exploring the use of LAB that everyone talks about, maybe its better. This way seems pretty fast though.

Hi - The Photoshop User/PhotoshopTV guys did a session on a method that requires no eyeballing/guesswork.

Step 1: You first set White and Black points with the threshold tool. To do this, open a Threshold Layer, which pulls up a histogram and turns the image into black and white (no grays). Push the slider all the way to the left and work up (right). The screen should be white. Mark the first visible (black) pixel. (Mark: Shift-Click with Eyedropper tool set at Point Sample.) That's your black point. Go all the way to the right and work down (left). The screen should be black. Mark the first visible (white) pixel. That's your white point. (NOTE: It's good to briefly uncheck the "Preview" option, just to make sure that you're not marking a piece of dust, etc.) Once you mark both points, discard/cancel the Threshold layer.

Step 2: Create a neutral/middle gray Solid Colour layer. Set the blend mode to "Difference". Open a new Threshold Layer. Push the slider all the way to the left and work up. Mark the first visible pixel - that should be middle gray. Cancel/discard the Threshold Layer. Discard the Solid Colour layer.

Step 3: Open a Curves Layer. Use the three eyedroppers to set the Black - White - Middle Gray points. Save this layer.

For most images, I skip the middle step; setting the white and black points is sufficient. If I'm worried about colour cast, then I do the middle step.

You can probably find better instructions and a full explanation at the Photoshop TV site.

Good luck.

The method Heller described makes a lot of sense to me, when one is looking for locating the white, black and middle grey points.

What I would like to add is that there is a flaw in Photoshop's method for color correction via the middle eye dropper. Using that for color correction introduces new deviations from the original. To avoid this, one should use the highlight eyedropper, applying Heller's neutral grey layer to the middle grey point, if there is a color cast in the latter and it should actually be neutral grey.