What the heck is "White Balance" anyway?

If you take pictures, you've heard the term "White Balance". Maybe you saw it in the instruction manual of your digicam, or in a post about photography. But what is it? Simply put, it is how white white is; if you pointed your camera at a truly white object, how accurate would the picture be? This is important if you take pictures of graffiti, which are often shot outdoors and sometimes at night. Amy Renfrey from www.DigitalPhotographySuccess.com
wrote a little piece about the subject which she has allowed me to post here:

Understanding White Balance

In digital photography terms, and traditional, you will most likely hear the term “white balance” quite a lot. It’s an important meaning because many digital photography enthusiasts concentrate on the lenses and digital camera without first learning about how light works.

In a nutshell, “white balance” in digital photography relates to the ‘temperature’ of light. If you notice when doing your digital photography indoors, the photo will have a bluish colour through out the digital photo. Then if you take your digital photography outside you will notice the photo then has a warmer tone to it. This is your white balance feature on your digital camera working to adjust the image.

To give you a direct example of how white balance works in your digital photography think of this; have you ever noticed how your colour pictures come out a more bluish tone in the shade? The problem is that because light has temperature, the camera has to analyze this change in its own limited way compared to the human eye.

You can help reduce the blue by altering the setting on the camera or adding a warmer color filter such as yellow. Some colour filters have different shades or hues of the same colour. Each warmer colour filter moves towards a warmer feel and increases in density.

Your white balance in digital photography also works when you walk into an office building. The fluorescent light might be different from that of the doctor’s or a drug store? Well, you’re not imagining things! The reason is there are over 40 different ranges of fluorescent lights and the problem for us digital photographers is that each one has its own colour temperature. It’s not to be avoided, please no! It just means you need to be aware that all florescent lighting is not the same and that you’ll have to consider this when shooting under this type of light.

You can work well with white balance by switching indoor shots to an “outdoor” setting to eliminate the bluish tone in indoor shots. And alternatively you can set the white balance mode to “indoor” when you are outside to reduce some golden/yellow saturation in your outside digital photography shots.

Another word on cameras

As you might imagine the paradigm shift from traditional film-based photography to digital is rapidly creating new opportunities to learn and grow. The photography industry is moving at an incessant pace, and digital cameras sales have surpassed their film-based cousin at an alarming rate each year. On January 16, 2004, Eastman Kodak announced it would end its sales of film cameras in the United States and on June 15, 2005, Kodak announced it will discontinue production of black-and-white photographic paper by the end of the year as it continues its transition to digital photography. Soon digital cameras will hit critical mass and film will only represent a minute segment of the industry.

What are the main differences?

The differentiator between a traditional 35mm film camera and digital cameras is how the pictures are captured, processed, and stored. A conventional camera exposes an image on a roll of silver-halide coated film. A digital camera captures an image on a photosensitive silicon computer chip called a charged couple device, also known as a CCD. The camera converts the image captured by the chip into digital data and saves it in a camera's memory as a digital photo. These photos can then be copied onto your computer's hard drive where you can email, edit, and save them.

CAMERA SELECTION

Just as with traditional film cameras, digital cameras come in two offerings: point and shoot, and digital single lens reflex (DSLR).

Both types of camera use flash memory cards (“digital film”) to store images and are immediately available for viewing through the camera’s rear liquid crystal display (LCD).

Point and Shoot

Point-and-shoot cameras are extremely affordable and remain the most popular in current market conditions. These cameras are easy to use, give outstanding results, and for all practical purposes are compact. Point-and-shoot cameras mainly offer a limited feature set, offering mostly automatic features such as: auto flash, auto exposure, and the camera selects the shutter speed and aperture for you. Cell phone cameras are low-end point-and-shoot.

Digital Single Lens Reflex (DSLR)

Digital SLR cameras offer photographers the ability to use interchangeable lenses and accessories, which give the photographer greater artistic control and flexibility. DSLR cameras allow photographers to visually check image sharpness and composition. The effects of changing lenses, changing exposure values, and viewing the camera's hisogram are immediately visible in the LCD viewfinder and/or eye viewer. There are many advantages of using DSLR digital cameras. They can handle a variety of lighting and focusing situations unlike point and shoot cameras. DSLR cameras offer optical zoom as opposed to just digital zoom, which essentially crops pixel data and will add unwanted noise to an image.

IMPORTANT TIPS

• Look for cameras that can save files in RAW. Saving your image as a RAW file will provide you with a higher quality image to work from in post processing. Images shot in RAW remain uncompressed, unlike JPEG images. Through repetitive opening/closing of JPEG files image -- image degradation occurs.

• Equally important is finding a camera with a minimal amount of shutter lag. It can be rather frustrating with some of the point and shoot cameras available when there is a long lag between clicking the shutter and the camera taking the shot. Choose a camera with a large buffer memory. This allows a number of images to be continually snapped before stopping to allow them to be downloaded and processed.

• Digital camera quality and the size of the created images are continually rising. As a general rule you will need at least 1800 x 1400 pixels (2.5 mega pixels) to print up to 6 x 4 inch with good quality. To date recommendations include the Canon Rebel XT (8.0 Mega Pixels), Canon EOS 20D, Nikon D70 and so on.

DIGITAL FILM: FLASH MEMORY

Manufacturers of cameras, namely Canon, Olympus, and Sony use memory cards that are usually not compatible with one another. Canon uses compact flash cards and/or IBM micro drives. A micro drive is similar to a compact flash card, but it was formerly recognized for its larger capacity. Olympus uses an xD Picture card and smart media card, and finally there’s Sony. Sony uses a memory stick. File formats generated by flash memory for digital cameras are RAW, TIFF, JPEG. RAW being a memory intensive format uses several megabytes of data on a memory card and does not compress the image at all.

Both RAW and TIFF are known as ‘lossless’ file formats because compression algorithms are absent, thus giving the photographer more pixel data and better image quality. However, since RAW is not as widely recognized as JPEG in the photography marketplace, special conversion software is necessary to convert images from RAW to TIFF or JPG. Some camera manufacturers include RAW conversion software with their higher end point-and-shoot and DSLR cameras, but it is not as great as some RAW applications developed by cutting edge companies such as PhaseOne, a Danish company that markets an outstanding product called Capture One DSLR. It is made specifically for photographers that wish to process RAW files.

One peripheral that will save battery life on your camera is a compact flash card reader. It plugs into your USB port and permits you to download your images by inserting a memory card in it. This is preferred over downloading from your camera/cable because your camera’s battery juice will quickly render your camera's battery dead, especially if you are downloading several hundred photographs. The memory card reader acts as an auxiliary drive. Just make sure you get a memory card reader specifically made for your type of memory card and that it can handle a high capacity card such, i.e. 4GB (Gigabyte) flash card.

At graffitipix.com, we use mainly a 10-megapixel Canon camera and save in RAW format. That's why our prints look soooo good!

Molly

A (brief) word about digital cameras

One of my recent posts talked about scanners and scanning technology. While a good scanner does an amazing job with flat art, obviously you cannot take your scanner downtown to scan the side of a building!

Once upon a time, you had to use a film camera to take a picture, and even up until a couple of years ago, you still needed film for high-quality pictures. At graffitipix.com, we make hi-end prints, and in order to do that you *must* start with a high-quality original.

Today's "good" digital cameras are now capable of creating high-quality original images. What constitutes a "good" image, or for that matter a "good" digital camera?

Just as with scanners, quality revolves around three criteria: spatial resolution, color depth, and optics.

Digital cameras, like flat-bed scanners, use CCD (Charge-Coupled Device) chips to "see". These are light-sensitive chips that convert an image into digital information.

CCD's are tiny matrixes of silicon that react to light. The size of the matrix i.e. number of rows and columns determine the spatial resolution of the image. A 2000 x 2000 matrix results in a 4,000,000 pixel (4 megapixel) image. Some cameras use software to create higher resolution, but basically thats how it works.

Color depth refers to how many shades, or gradations each pixel can be (most CCD's are 24-32 bit, meaning they can create millions of shades for each pixel).

The optics, of course, refer to the lense and the mechanics used to focus the light on the CCD.

Though decent CCD's are increasingly put into cel phones, you still need one of the 'better' digital cameras to create a good-quality original.

More on this shortly...

Molly