04 Dec 2005 White Balance (Podcast 14)
Welcome to this weeks episode which is number 14. Firstly I’d like to congratulate a member of my site, Philip, who uses the login name Damaxx, as Philip was chosen winner of the November MBP Active Member Prize! Philip chose a photo I made in November this year with my EOS 5D of a hawk in a tree at dusk. The moon was rising behind the hawk, kind of small in the frame, but adding to the mood. If you want to take a look at the shot which I titled “Moon Hawk”, it is number 754 in my online gallery at martinbaileyphotography.com.
Also, before we move on to the main topic for today, I’d like to apologize for and correct a mistake I made in episode 12 on my Digital Workflow. I said in the show that the Capture Sharpener in the PhotoKit Sharpener plugin for Photoshop is for use with scanned film only and for that reason I don’t use it. However, a listener and member on my Web site, Howard Grill, kindly pointed out that the Capture Sharpener does in fact have applications for images taken with a digital camera. Indeed another look at the pull-down list does reveal that it does contain sharpeners for images made with digital cameras and scanning backs etc. In the manual, it recommends that you use these early in the workflow to be able to see the effect of the sharpening. I personally probably won’t be doing that myself, but the options and description of the use is there and I’d missed it, so thanks again Howard for pointing out my mistake. I stand corrected.
So let’s get down to this weeks main topic. Following a recent thread in my forum on White Balance, I’m going to talk about how I deal with White Balance. I’ll put a link to the thread in the notes for this episode. I’m not going to go into much technical detail about why we need to balance our whites, because there’s a great explanation of this on the site that sparked the discussion on the forum. The site is Sean McHugh’s “Cambridge in Colour”. I’ll include a link to the article on Understanding White Balance and while you’re there you might want to check out some of the other areas of the site.
I will explain briefly though why we need to White Balance. Basically, the human eye already has the best Auto White Balance functionality built in so we don’t really notice the difference in the colour of light. However, our camera’s can’t do this as accurately so we sometimes need to give it a hand. It is also important to know when to do this, as the colour of the light in a photograph helps us to understand the conditions under which the image was shot, so we don’t always want to standardize it. Light comes in many colours.
The colour of sunlight changes throughout the day, even if there isn’t a cloud in the sky. It is much warmer than the light on a cloudy day. If we want to ensure that our images look like they are taken on a cloudy day, we could continue to shoot in the daylight white balance mode.
Also note that outside, even on a sunny day, although the light is quite evenly balanced during the middle of the day, when the sun is low in the sky in the morning or evening, the light is much warmer, and therefore orange or golden. It is because of this though that we call this the golden time or the golden hours, and also because of the magical quality of this light, that we really don’t want to correct this. So I often stay in daylight mode whenever I’m outside in natural light. That is without any artificial light.
There are times though when not correcting the white balance will give your images a strong colour cast, which will usually not be desirable. Standard Tungsten Light for example, is much warmer than sunlight, and so we have to set our cameras to balance the difference. This is much like selecting Tungsten balanced film instead of the daylight balanced film that is more common, but as with the ISO, with digital we no longer have to change the film, we just need to press a few buttons. Note though that there are some Photographic Tungsten Lights available that are already balance much cooler, or bluer than normal Tungsten lights, and much closer to daylight, so just setting your camera to Tungsten White Balance may not produce the desired results here either. Other light sources such as light bulbs and fluorescent lighting have other colour temperatures which all can be corrected unless you want the effects that they would give the image without correction.
I should say that never use auto white balance, where you allow the camera to guess what the white balance should be. I’ve heard that modern DSLRs are now relatively good at getting white balances correct much of the time, but I like to keep a little more control over the white balance. This is also because I tend to shoot a lot of bright colours or the whole frame is often filled with one particular colour like orange, red or green, and these colours can quite easily fool the camera into thinking that I am under artificial light.
I’d say that probably 90% of the time instead of using AWB or auto white balance, I shoot using one of the presets. On Canon Camera you can choose from the Daylight, Shade, Cloudy, Tungsten Light, White Fluorescent Light or Flash presets. I find these presets to be close enough for the majority of applications. I also sometimes switch to Manual white balance mode and select the Color Temperature in Kelvin from the camera’s menu.
For the last few years my Canon DSLRs also have the ability to fine tune white balance based not just on Colour temperature, but also by moving towards blue, amber, green or magenta. This is done via the menu on the LCD panel, using a 2 dimensional grid. On the 5D for example you have green on the top, amber on the right, magenta on the bottom and blue on the left. You can move a pointer along the vertical axis to move between green and magenta in varying degrees, or the horizontal axis, between blue and amber. You can also move the pointer out in any direction, giving you varying degrees of the combinations, like moving slightly towards the green and amber. I must say though, that I’ve never used this feature in the field. This is really for two reasons, one is that I always shoot RAW, so I can change the white balance in post processing if necessary. The other is because I use the custom white balance feature for around 10% of my work. This is the times when I am not confident that I can get accurate white balance with the presets or by selecting the colour temperature. Or I just want to make sure that I get the white balance just right. In these cases I use Custom White Balance, which terminology wise also falls under Manual white balance on Canon Digital SLR cameras.
To input a custom white balance, you need to photograph either a white card or a gray card, ensuring that the circle in the center of the focusing screen, which marks the area used in spot metering, is fully filled with the card and nothing else. The surface of the card will reflect light a little differently depending on the angle I shoot it from, so I usually tilt the card towards the sun or light source a little when shooting.
Once you’ve shot an image with your white or gray card in the center to use as a reference for your white balance, you have to select the Custom White Balance from the camera’s menu. The camera will then display the images on your memory card and ask you select one. If your reference shot was the last one you took, it will already be displayed on the LCD and you just have to select it. If not, you’ll have to navigate to the shot and then select it. After you select the reference image for custom white balance, you also have to select Manual White Balance in the list where you usually select the other presets. If you don’t select this, you’ll continue to shoot using the preset, or worse still, AWB if that is what you were using. After selecting Manual White Balance you will continue to shoot with that white balance until you change the selection again.
If you only shoot JPEG, you need to use this method to get the White Balance right in difficult light conditions, because the colour of your preferred white is burned into the JPEG when it is processed within your camera and the RAW data thrown away.
If you shoot in RAW, you can as I do still shoot with the custom white balance from the white or gray card to reduce post processing effort. However, you can also just ensure that you have the white or gray card in the frame in one shot, and then get the white balance from the card during post processing with a colour picker and apply that to your RAW images as necessary.
You’ve probably noticed that a number of times I’ve mentioned using a gray card instead of a white card. It doesn’t really matter which you use, but the surface needs to be of neutral colour. I.e. it should not have any colour tints what so ever, and gray apparently reflects all colors through the spectrum equally. I personally don’t use white because it can be highly reflective, and can be made falsely white by over exposure. To date I’ve used an 18% gray card. 18% gray is also good to meter for accurate exposure, so I always carry one measuring 4 by 5 inches in my photographer’s vest pocket.
I also attached a Gretag Macbeth Mini-Color Checker card to the edge of my gray card, so I have a colour reference in the shot that I take to set the custom white balance. I have not posted this in my online gallery, as it does not really belong, but if you are listening in iTunes, the image attached is one that I took in the field earlier this year. I will also link this to a post in the forum, so you can see it on my site too if you don’t use iTunes. I’ll put a link to this too in the show notes.
I put the colour checker card in to help me balance the colour when prining too, but the fun thing with doing this too is you can actually select the other colours on the gray card with the colour picker to set the white balance, which creates some weird effects. This can actually be a learning experience too, as you can see how various colours of light would affect the image. If you select red as the reference for example, the image takes on a harsh blue-green cast. If you select blue, the image takes on a hot reddish orange cast. This helps to see which colours counter out which other colours, and just helps to get a grasp of the concept.
Anyway, of the shots made with the custom white balance set earlier, there’s one shot in my Online Gallery, which is photo number 619. As usual you can view the shot in iTunes or on my Web site by entering 619 into the field on the top page or the Podcast page and clicking the orange button. Or click the thumbnail in the table on my Podcasts page. Just look for episode 14.
We’re almost done on White balance in general and how I set my custom white balance. However, I have one problem with my current method, and that is the card I have is quite old in design, being originally to set exposure rather than white balance, it has a slightly rough surface. This won’t really change the results if I simply use the card to set the custom white balance in the field, but what I find is that I can click various areas of the gray card in post processing and get slightly difference readings. Again going back to the thread that sparked this week’s Podcast, a product called WhiBal was discussed and actually ordered by a number of the members, including myself. The WhiBal set of cards has white and a number of gray cards, and some inventive ways of either hanging them around your neck or attaching them to your clothes or equipment for easy access. The main reason I’ve ordered mine in preference of my current method is that the surface of the cards appears to be much smoother than my current card, and also they are designed for white balancing, and not for setting exposure. I think I’ll find some way of getting my Gretag Macbeth Mini-Color Checker card into the shot as well as the WhiBal once it arrives. I’ll also include a link to the WhiBal site from the thread, so if you are interested in this too, please take a look.
So, that’s about it for this week. As usual, this has been just my take on White Balance and what I do in my photography. If you have any other suggestions or comments, swing by the forum at martinbaileyphotography.com and post them in the thread discussing this. Again the link is in the show notes. Also, of course you can post anything else you like, feedback about the show in general just general chat. You can also contact me directly via private mail from the forum or if you haven’t registered yet, you can use the Contact Form from the top page or Podcast page on my site.
Finally, thanks to those that have voted for the Martin Bailey Photography Podcast on Yahoo! and Podcast Alley. If you have cast your vote yet and like the show, please drop by these sites and do so.
Have a great week, happy shooting, and I’ll see you next week.
The Music in the first 28 Podcasts is copyright of William Cushman © 2005, used with kind permission.
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Posted on behalf of Martin by Michael Rammell, a Wedding Photographer based in Berkshire, England. Michael also has a long-standing passion for Nature & Landscape photography. To catch up with Michael, visit his Web site, and follow him on the following social networking services.
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