Many digital cameras provide the option for you to shoot in raw, this enables you to open your images in Photoshop and edit them in 16-bit mode rather than the 8-bit mode you get with standard JPEG images.
There are times when you mat want to shoot in JPEG and the reasons may be to reduce file size or increase workflow speed. However, some photographers don’t understand the benefits of being able to edit their images in 16-bit and in order to do this you need to shoot in raw.
A Rough Guide To 8 Bit
Every color in a digital image is made up of some combination of the three primary colors of light – red, green and blue:
It doesn’t matter what color you’re looking at on your screen. It’s being made up of some combination of those three colors.
By using multiple shades of red, green and blue! The more shades of each color you have to work with and mix together, the more colors you can create.
An 8-bit image has 256 shades of red, 256 shades of green, and 256 shades of blue, giving you the millions of possible colors you usually see in a digital photo:
Where does the number 256 come from? Well, 1-bit equals 2. When you move beyond 1-bit, you find its value using the expression “2 to the exponent (however many bits there are)”. So, for example, to find the value of 2-bits, you would calculate “2 to the exponent 2”, or “2 x 2”, which equals 4. So 2-bits equals 4.
Don’t worry if you found that confusing, or even worse, boring. It all has to do with how computers work. Just remember that when you save an image as a JPEG, you’re saving it as an 8-bit image, which gives you 256 shades each of red, green, and blue, for a total of 16.8 million possible colors.
If you had two identical photos open on your screen in Photoshop, the only difference being that one version was in 16-bit mode with its trillions of possible colors and the other was in 8-bit mode with its 16.8 million possible colors, you might think that the 16-bit version would look better, since it’s capable of displaying far more colors than the 8-bit version. But the simple fact is, most photos don’t need 16.8 million colors, let alone trillions of colors, to accurately reproduce their contents. They usually contain several hundred thousand colors at best, although some may reach into the low millions depending on their subject (and depending on the size of the photo as well, since you would need millions of pixels in order to see millions of different colors).
Did you know that when an 8-bit version and a 16-bit version of an identical image are placed side by side, theywill look identical to us. The main reason for this is due to the fact that the human eye can’t see 16.8 million colors, so you might be wondering why you should bother editing in 16 Bit mode.
So why, then, would it be better to work with a 16-bit image? Simple, flexibility. When you’re editing an image in Photoshop, sooner or later, if you continue making edits, you’re going to run into problems. The most common problem is what’s known as “banding”, where you’ve lost so much detail in the image that Photoshop can no longer display smooth transitions from one color to the next. Instead, you get an ugly stair-stepping effect between colors and tonal values.
So how can you take advantage of 16-bit with your own photos? Simple. Shoot your photos in the raw format instead of JPEG whenever possible (assuming of course that your camera supports raw), then open and edit them in Photoshop as 16-bit images. Keep in mind though that when working with 16-bit images, the file size is much larger than you’d have with an 8-bit image, and if you have an older computer, it could have an impact on how long it takes you to work in Photoshop. Also, although each new version of Photoshop gets better and better with this, not every filter and adjustment is available to us in 16-bit mode, but most of the commonly used ones are. If you find that you do need to switch to 8-bit at some point because your computer is running too slow or the filter you want to use is unavailable, you can switch to 8-bit mode by going up to the Image menu at the top of the screen, choosing Mode, and then choosing 8 Bits/Channel. Try to work in 16-bit mode for as long as possible though before switching to 8-bit mode. Also, make sure you switch to 8-bit mode before printing the image, or even better, save your 16-bit version as a Photoshop .PSD file and then save a separate 8-bit version for printing.