White Balance, or How I Learned to Stop Worrying and Shoot RAW

In photography, “white balancing” is at its essence the act of correcting the colors in your photographs. In other words, it’s the act of getting the whites you saw when you were taking to the picture to also be white in the final photograph.

Different sources of light (tungsten, florescent, sunlight, etc.) all have different color temperatures. Color temperature is essentially how cold,warm, or neutral a light source is. In terms of your photograph, the temperature of a light has the ability to cast a certain color over your end result - a result we sometimes seek to alter by manipulating the color balance of a photo. The salient things to know about color temperature are that it’s measured in Kelvin (K) and that 5000K is about neutral. Anything below 5000K tends to produce a ‘warm’ orange cast on a photograph and anything above 5000K tends to produce a ‘cold’ blue cast on a photograph. Of course, these casts may be desired depending on how you wish your final result to look.

The process of white balancing is thankfully not so tedious on digital equipment. If you are shooting on a digital SLR, there is most often a menu option (refer to your camera manual) that allows you to set a custom white balance based on the lighting. Most of the time, there are many preset balances. For instance, if you’re in a room lit only by tungsten bulbs, use the tungsten white balance setting on your camera to account for awkward color casts. That’ll generally get you started in the right direction.

Now a fundamental problem arises: what if you select an incorrect white balance setting? If you are saving your images to JPEGs, changing white balance is a bit more involved, not to mention a destructive file process. What!? I don’t want to destroy my files! Well thankfully most, if not all digital SLRs allow you to save your photos in a RAW file format.

The RAW file format is ostensibly the unadulterated, unprocessed data from your camera’s image sensor. The JPEG format in constrast is a compressed format with settings like white balance permanently attached to the file. It might be easier to think of RAW and JPEG as being analgous to film: RAW is like the exposed unprocessed film negative whereas JPEG is like a certain processed version of that film negative.

With RAW, we have manual control over many settings including sharpening, color saturation levels, and notable to this article, white balance settings. Of course, we need software that can handle the RAW format (I use and recommend Adobe Lightroom). This ability to manually change many settings that we would normally be forced to determine in the moment of photographing allows for a wealth of possibilities with our images in post-processing.

Why not shoot RAW exclusively? Well, because RAW data is mostly uncompressed, it takes up a lot more space than JPEG images (which are by definition compressed). How much larger are they? Often it’s a factor of about ten, so a 1 MB JPEG image will be 10 MB if saved as RAW. There is generally a direct correlation of how many ‘megapixels’ your digital SLR produces.

There is no one ‘perfect’ white balance for all your photographs. The best way to get great results with white balancing is to experiment! You can create some very beautiful and even very otherworldly photographs by altering white balance settings. Plus, it’s digital so we’ve got nothing to lose and everything to gain! Take some photos and share what you’ve got with the rest of us.

protip: most flashes are also set to 5500K, which is roughly the temperature of sunlight around noon-ish

Small correction: Though a good rule, RAW files are not always derivative of megapixel number - the 10 megapixel Canon 40D has 14-bit images and the corresponding RAW files are about 14mb in size to compensate for additional color information stored in the channels.

@scott: Yeah color depth is important to consider as well, but I was trying to give a general indication about file size. Thanks for reading!

Can you explain why Lightroom has a tint slider as well as temperature adjustment? Isn’t temperature all you need to adjust for achieving a correct white balance.

@noah: The tint slider is there to account for possible color casts that are green or purple. It takes some training your eye, but particularly in skin tones you will occasionally see a purple or greenish cast, which is where this slider would come in handy.