Correcting White Balance in Photoshop and Adobe Camera Raw
As a general rule of thumb, it is best to correct for white balance problems at your earliest opportunity. For film shooters, this means the use of color conversion filters such as 81-series warming or 80-series cooling filters. Those shooting digital have other options. Last week I covered the basics of white balance and how to adjust your digital camera to electronically compensate for it, so this week we turn our attention to how color temperature can be compensated for via software post-capture. Although I am going to cover Adobe Camera Raw and Photoshop specifically, the concepts are equally useful for those using other programs.
If you are shooting in jpeg or tiff formats, you may as well skip down a couple of paragraphs, but for those working in raw, your first software stop on the road to optimizing images will be in some other raw file conversion program. Until you do in fact, your raw files aren't really so much images as they are merely collections of data from your camera's sensor. As I've mentioned previously, many such programs are proprietary and work only with raw files from specific camera brands, but the most widely used program that is compatible with the majority of digital cameras is Adobe Camera Raw. Along with the other various controls it offers for tailoring the raw conversion process are those that affect white balance.
Getting the white balance the way you want it in Adobe Camera Raw will not only save you having to do it later, it is also the best way to it. Regardless of how you had white balance set in your camera, you can feel free to change it here with no loss of quality whatsoever. This is one of many advantages of shooting raw: you can see your image while you fine tune its white balance. Adobe includes this at the top of the list of controls in Adobe Camera Raw and it should be among the first things you adjust when you open your images in ACR.
If you don't shoot raw or have already opened your raw image in Photoshop and still want to make some tweaks to its white balance, never fear. Newer versions of Photoshop do provide some reasonably good tools for fixing problems with color temperature. Introduced in Photoshop CS, Adobe now provides digital equivalents of standard color conversion and color correction filters. These sorts of filters were pioneered by third-party companies such as Nik Software, but it is nice having them included now at no additional cost directly in Photoshop.
For some inexplicable reason, Photo Filters are not located on the Filter menu in Photoshop. Instead, Adobe hid them over at Image >> Adjustments >> Photo Filter. Opening the Photo Filter dialog reveals the window shown here. Via the dropdown, you can select from a list of standard warming, cooling and color correction filters, or, by selecting the option underneath it, you can pick any color you prefer. Below that is a slider that will let you choose the Density or strength of the resulting effect. With the Preview option checked, you can use the color and density controls to get just the effect you are after. At the bottom of the dialog is a checkbox for "Preserve Luminosity" that you want to be sure is checked to keep the effect looking natural.
A better way to apply Photo Filters though is on an adjustment layer. To create the layer, either use Layer >> New Adjustment Layer on the menu, or click on the small, black and white circle icon at the bottom of the layers palette. From the pop up menu, select "Photo Filter" and proceed as above. This way, you can use the filter without having to actually alter your underlying image. For more fun, adjust the opacity of your filter layer to tweak the strength of the effect. Also, you can later double-click on the Photo Filter icon in the layer you created to alter it's settings with no cumulative loss of quality. And, since the filter is on a layer, you can trash the whole thing later on if you decide you don't like it.
Our eyes and brain do an amazing job of compensating automatically for color temperature under varying lighting conditions. Almost too good, since our cameras tend to see an existing color cast even when we can't. It can be both surprising and disappointing to get slides back with an obvious orange or blue bias to them that you were unaware of at the time of shooting them. Digital affords us the opportunity to more easily create images the way we actually saw them in the field (or the way we wish we saw them). In order to do so though, it is necessary to understand the tools available to correct for white balance in the digital darkroom. Hopefully this week's tip will give you some ideas on what can be done and how to go about doing it.