In the universe of digital photography, most camera users believe that the control they have over their images is confined to making changes to the traditional shutter speed and aperture controls — much like they did with their older film cameras.

The belief is that other than getting a correct exposure, there is not much else to do until they get the file into Adobe Photoshop. They simply set the exposure control and, after creating the photograph, transfer the JPEG file in either sRGB or Adobe RGB colorspace onto their computer, launch Photoshop, and let the magic begin.

What many photographers don’t know, and many others chose to ignore, is that there is a step in between the image creation and the file transfer to the computer over which they may want to have control. Rather than allowing the camera software to decide on the color conversion and file format, it could make more sense to work directly with the raw files.

Although it should be noted that not all digital cameras allow you to work with the raw file format, those that do give you additional control over your images.

Control over images

What exactly is a raw file?

Let’s look at what happens when a digital image is created inside a camera. A common sensor inside a digital camera consists of numerous light-sensitive sites, each capable of recording red, green, or blue light. These sites are laid out in an array like the one shown in Figure 1.

Fig. 1

Each of the sites records a small element of the photograph, commonly referred to as a picture element: pixel for short. The camera software takes the single red, green or blue data recorded for each pixel and calculates the two missing channels for each pixel. At this stage you have a raw file and a decision to make.

Cameras are programmed to take the raw image and perform several tasks. These include performing a white or gray balance, adjusting the image contrast and saturation, sharpening the image, converting the file from the native 12- or 14-bit into an 8-bit file, converting the image into to a new colorspace, converting it into the JPEG file format, and, finally, compressing and saving the resulting file.

The problem? Quite often, this is a “one size fits all” process, despite the original image characteristics.

Before jumping on bandwagon…

Before jumping onto the raw bandwagon, keep in mind there are some advantages to be gained by allowing the camera to simply do its thing.

For one, images are smaller so more of them can fit onto a memory card. Setting your camera to shoot raw can also often slow the camera down. You don’t need to take the time to manually convert your images, you don’t need to learn how to process the raw files, and often the JPEG files a digital camera produces are simply good enough for many purposes.

So, you might ask why you would want to put in the effort to work with raw images.

In a nutshell, if your image isn’t a simple family snapshot and will be viewed by an audience that will appreciate the additional quality that can be obtained by working with raw images (this would not be anyone in my family), it can make sense to take the time to learn how to work with this file type.

Think of a raw image as if it were a piece of film from one of those ancient cameras that you used to use. Just as you could change developer, processing times and processing methods to modify the “look” and aesthetic details of the photo, you can work with the raw image to give you a better starting point before you bring the digital file into your image editing program.

Smoother gradients possible

Once an image has had its contrast and saturation modified in the camera software, it can be difficult if not impossible to restore detail that might have been lost in the process.

With raw, you not only have far greater control over these processes, you can always return to the original raw image if you need to start over or if you have new output equipment that would benefit from a modification of the image processing.  Color temperature, exposure, shadow detail, brightness, contrast, saturation and image sharpness tools are all at your disposal when working with raw images.

You can work with individual color channels or the composite image. But for some, the most important benefit in working with raw images is in the ability to work with the resulting 16-bit images in Photoshop. Images that have a 16-bit depth rather than an 8-bit depth can have smoother gradients and improved tone separation.

Next time, we’ll take a look at working with raw images in detail as well as the Photoshop Camera Raw interface. In the meantime, check your camera and see if you can save your images in the raw format. Shoot a few test images and save them as both raw and in your favorite default flavor. That way you will be able to do real-world comparisons and see for yourself if raw is for you.

John Nate is a senior color specialist for Chromaticity Inc., an integrator of color technologies for the newspaper and other industries. He can be reached at 616.988.6119, or via e-mail at jnate@chromaticity.com.