I've been putting together some narrow focus blogs on photography stuff lately and I thought I'd cover a more general subject that applies to everyone (who owns a camera anyway!).

I'm going to talk today about White Balance, and by association Color Temp. Let's start by going through a very quick overview of what these two things are:

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White Balance:

When photographers talk about white balance what they really mean is color temperature, which is to say they are trying to find the correct color temperature for a given shot...where 'white is balanced' so to speak. So White Balance is a verb as much as an adjective.

Confused yet? Yes? Perfect! We'll cover this more in a minute.

Color Temperature:

Color temp refers to the overall color cast (or tint...or and tint for those of you familiar with Adobe's RAW converter). If that doesn't make sense right away, don't worry...we'll look at some examples in a second.

A good rule of thumb when thinking about color temp is to place it into two camps.

1. Warm (sunset, fire, volcano, incandescent light, late afternoon sun, headlights etc)
2. Cool (ice, water, rain, fog, early morning sun, snow etc)

The above is a big simplification of color temperature but it's fine for the moment so let's move on to some examples.

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Take a look at the below image (I love lofts so I'm going to be using examples from one of my shoots yesterday). Notice any difference between the three images? Well, it's probably pretty easy to see and I've exaggerated the difference to illustrate the point.

The image on the left has been poorly white balanced, it's color temp. is too cool (too much blue, cyan, etc). The image on the right is also a problem, it's too warm (too much red, orange, magenta). The image in the middle is about right.

Actually, the image in the middle, strictly speaking isn't truly white balanced but we'll go more into that in a bit. For the moment I just want you to really 'see' the difference the color temp has on photos.

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Ok, so we can now see that photos can have a color cast a.k.a. color temperature and that we need to get that sorted properly (white balance) or we might end up with an odd looking photo.

So how do we do that? As with most things in life, there are a couple different ways.

The Camera: 

I know a little something about your camera. Really. I don't even know what type you have, but I know just how it's going to handle white balance. Poorly.

You see cameras don't do a very good job figuring out the color temp of a given scene should be no matter how hard they try...and that goes from the cheapest P&S to a $10K DSLR. They all struggle. They just can't 'see' what the color should be. Of course, there is a method to work around that.

You can tell them. 

Most cameras and any DSLR will have settings that allow you the photographer, to tell the camera what type of light you are shooting under. This is critical to getting a good color temp because so much of an image's color cast is determined by the type of light illuminating it.

You may also opt to shoot what photographers call a 'gray card' if your camera has the option (literally this fancy device is just a bit of gray cardboard). You can then tell your camera to 'look' at the photo you've just taken and determine what the correct white balance should be.

This is probably a good time to point out that the term 'white balance' is a crummy name. Or at least confusing when it comes to actually sorting out the color cast. You see, it's really better to use a gray reference point instead of a white one. White too easily holds a color cast which can lead to exaggerated results, it's also prone to blow out during exposure which can leave you with nothing to balance from.

All of the above works fine, but I suggest you forget all about in favor of what I am about to cover.

Post Processing:

Sure, you could do all that stuff above...and you can weave your own clothes or start a fire by rubbing two sticks together also. But there's a much easier way nowadays and a lot more flexible as well.

Here's a screenshot from the Adobe Camera Raw loader. I've scrunched it down a bit so it's easier to see in a blog but it's the same basic deal.

In the upper left, along the top bar you can see that I have a little 'eye dropper' selected. That's the White Balance tool. You then just click on an area in the image where something white is (or preferably gray) and voila...photoshop makes all the necessary color temp changes.

You can see on the right we have a readout of the specific temp and tint as well as a histogram of the RGB channels and the luminance channel. Don't worry about all that right now...that's in the 201 class.

BTW, I should mention this handy feature only works if you shoot RAW. If you are shooting jpeg's your camera is forced to make a white balance decision for you and you are stuck with that (sort of).

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Balancing Color Temperature Manually:

If you are shooting some sort of non RAW file type (commonly jpeg) then you are image has already been 'set in stone' so to speak regarding white balance. But that doesn't mean you can't attempt to fix it by re-balancing the colors manually.

Just a word of warning about manual color balance. Most people find it to be very difficult. In fact I know professionals that still struggle with manual balancing. It's just not an easy skill. It takes a discerning eye, patience, and a lot of practice.

I don't want to scare you away from trying it, rather I don't want you to feel too discouraged if you have a hard time 'getting it just right'. It's NOT easy.

Fortunately photoshop puts a very good tool in our hands called 'color balance' (surprise!). It does the best it can to simplify the process by grouping opposing colors so that you aren't working against yourself during the balancing.

If you want to get your feet wet here I suggest sticking to midtones (they are the easiest) and just working with one 'group' at a time.

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Advanced Concepts:

If you've got all the above figured out you are doing great...but I have some bad news for you.

1. You'll almost always have more than one color temperature represented in an architectural shot...I've had photos that had as many as five, and those were just the critical areas!

Photos like this are notoriously hard to 'white balance' in fact they are impossible to so handle on a global basis. The classic example of this is any window. The room will almost always be warm compared to the window (which will be cooler)...never mind that you might have a mix of artificial light sources and color cast reflecting off bright furniture also!

You can handle these though...in most cases by balancing the photo twice (or five times!) for different areas of the photo and blending them together.

2. You seldom want to balance perfectly to white when working with interior shots. 

Of course this is a matter of opinion (just like everything I write) but I find one has to be careful about aiming for a perfect white balance when working with architectural shots. You may find the photos look very artificial and strange. This is because most interior light (especially common household t. filament bulbs) has a warm tone to it...so the room should have a little warm color cast to it if you want it to appear most natural.

3. You can manipulate color temp to your advantage during unfavorable weather.

I'll just skim this briefly (it deserves a blog of it's own) but you can monkey with color temp to make things appear much (better) then they are when working with exteriors. Skies can be made to appear blue (cooler temp) and foliage can appear 'sunnier' (warmer temp). Good stuff when you live in a rainy place, eh?!

Well, that's it for a bit. I'm in my busy season now so I won't be able to blog as often but will try to contribute as time allows. Hope this helps. :)

Cheers, -B