Black & White

[Donald]

Pierre

The card I have is pocket-sized WhiBal.

Once I am in location I shoot a frame of the WhiBal card. If I've got a wide angle lens on, then I'll do that once I've got my shot set up. If I've got a longer lens on and it's not feasible to hold the card at arms length in front of the lens, then I'll lay on a fencepost or some other object, or even the ground and take a frame. Then I'll recompose my shot.

Once back at the computer. How you correct all the other frames from that shoot depends on what RAW processor you use. With Canon's DPP, you click on the card in your first frame and save that WB setting. The it's just a case of clicking the 'dropper' tool on every other frame and the WB is corrected. You can mass-adjust.

With DxO Optics, I haven't found the shortcut (yet). So it's a case of taking the reading from that first frame and then adjusting to that same figure with the WB slider on all the others (if anyone knows a quick way to mass adjust, let me know).

[dan marchant]

Donald
When you use your grey card, I am curious how you use it. I have the Xrite card and have not used it yet for landscape images.
Thanks

There are several different ways. On most (?) cameras you can take a shot of the card and then import the WB from that image and set it to be used for the rest of the shots.

An alternative method (which I use) is to take a shot of the card, then just take the rest of the images and sort the WB when I process the RAW files.

I use ACR 6xx(as part of Photoshop Elements) but assume that most RAW processing software will allow you to batch adjust WB.
1. I open all the images at the same time,
2. click the card image so it is the active image (in the main processing window),
3. then Shift click to select all the other images.
4. With all images selected I then just use the WB dropper to sample the grey card and ACR then applies that WB to all the selected images.

The card is obviously an excellent source for setting the WB but you can of course use the same trick with no card, if one of the images contains a suitable reference, such as a white/grey shirt, wall or similar.

You can also use this to batch adjust exposure or other settings if you have a group of shots that were all taken of the same thing using the same settings (such as high speed sequence when shooting sports).

[revi]

The only problem I had with using a 'naturally occuring' gray patch was the way the patch was lighted. If it is in the shade,
it can be a lot cooler than you want (snow landscape), and if it gets reflected light from a coloured surface, good luck...

Worst example I had was on scene, where part of the lights were blue, others were yellow, and the scene was high contrast.
Not easy to find a well placed patch there :/

[Karen L]

Thank you all for the great information.