to Change the White Balance of a JPG
This is easy.
You can change the White Balance (WB) of any image you can open in Photoshop. It doesn't matter if its raw, TIF or JPG, and it doesn't matter if it's from a digital camera or from film.
Every version of Photoshop can do this. Elements may have a very slightly different way to get to the adjustment. I'm talking about all versions of Photoshop including at least versions 4, 5, 6, 7, CS, CS2, CS3, CS4 and maybe before.
You also can do this in almost every other image editor, including free ones like iPhoto. See here for these cheap or free software options. I'll cover how to do this with Photoshop. The other programs are similar.
I use Photoshop all day. You're even better off if you use LIghtroom, because the adjustments in Lightroom are both easier, and look better. Lightroom makes the best changes to WB and exposure of any program I've used, just that I'm too lazy to open Lightroom if I need to fix anything.
I set my White Balance as I shoot, so I rarely have to do this.
I also have a page loaded with Photoshop hints and tricks including correcting color casts.
HOW - TO
In Photoshop on the Mac, just hit Command (the Apple key) B. The hard way is to go to IMAGE > ADJUSTMENTS > COLOR BALANCE.
You'll see a box with three sliders.
To change color temperature simply move the Cyan/Red slider one way and the Yellow/Blue slider an equal amount the other way. Just do it until it looks good.
To change Green/Magenta bias with fluorescent and metal-halide lighting simply move the Green/Magenta slider until it looks right.
EASY! Save your image as you please and you're done. Smarter users do this in an adjustment layer.
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