Adjusting the color temperature of an image can make a big difference to the feel of the image. Usually people prefer a slightly warm color temperature rather than neutral, though if you want your image to have a cold look, you may want to adjust the color temperature to be cooler.
There are quite a few different ways to adjust the color temperature of a photo. Probably the easiest way is using the White Balance tool and color temperature slider in Adobe Camera Raw (ACR).
Using Adobe Camera Raw to adjust the color temperature
If you are working with a RAW file, you can just open the file in Photoshop and it should automatically open up Camera Raw. If you want to adjust a JPEG or TIFF file, then in Photoshop go to File > Open As...
In the Open As dialog, select the file you want to open, then change the 'Open As' option to Camera Raw (followed by a long list of RAW filetypes). Then click 'Open' to open the file in Camera Raw.
In ACR click the White Balance dropper tool (at the top of the window), and click on an area of the image that should be a neutral color (somewhere between dark gray and very light gray). Camera Raw will automatically select the correct color temperature and tint settings to make the area that you clicked neutral.
Probably you will want the image looking slightly warm rather than the more clinical neutral color balance, so adjust the temperature slider, and move it to the right slightly.
Using curves to adjust the color temperature
An alternative way to adjust the color temperature of an image, is by using a curves adjustment. This is more time consuming than using the white balance tool in Camera Raw, but has the benefit of allowing much finer control.
Photoshop Elements doesn't include a real curves adjustment ability, so doing a curves adjustment isn't as easy as it is in Photoshop CS. Still, it is possible to perform curves adjustments in Photoshop Elements, you will need to start by downloading and installing the Smart Curve Curves Adjustment for Photoshop Elements.
If you are using Photoshop Elements, you will need to install the Smart Curves filter, then open it via Filter > easy.Filter > SmartCurve. In the SmartCurve window, hover the mouse pointer over the preview image, and place the cursor over an area of the image that should be neutral.
In the top right hand corner of the SmartCurve window, you will see 3 figures for the Red, Green, and Blue values at the current mouse position. For a neutral subject, we want all 3 of these values to be the same, if your image has a color cast, the values are likely quite different.
Make a note of the Red, Green, and Blue values.
To correct the color cast using curves, change the Channel (on the right hand side, it will currently say 'RGB'). If your image has a red or cyan cast, first select the Red Channel. If the image has a Green or Magenta cast, select the green channel. If the image has a Blue or yellow cast, select the blue channel.
You now want to correct the curve for that channel so that the values are nearer to the other values. For example, if I have an image with the following values: R199, G176, B111. This image has a yellow tint, you can see the blue value there is far less than the red and green values.
So I select the blue channel and then add a point to the middle of the curve. Checking the In and Out values in top right hand corner of the Smart curves window, I place the point around 111. I now pull this point upwards. For a completely neutral image I should pull it to 176 (the same as the green value, and I would need to adjust the Red value as well), but I want a slightly warm image, so I pull it to 170.
You may find that after a single channel adjustment, your color temperature is correct, but often you will need to adjust two or all of the channels. Play around with the different channels, moving them up and down until you get a color balance you are happy with. In my example, I found that modifying the curves to give the final RGB values of R213, G194, B166 gave a pleasing color balance.
Dave Kennard writes for www.discoverdigitalphotography.com, offering photography tips and advice. The website covers all types of photography, including landscape, portrait, and macro, and is updated with new tips on a regular basis.
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