Archive for June, 2010

For the most part, designers don’t really think about bit depth when working in Adobe Photoshop. Bit depth tells Photoshop how many colors an image can contain. As of Photoshop CS5, a maximum of 32-bits can be used. It’s important to have at least a small understanding of what bit depth is and when you should use different bit depths when working with your images.

2-Bit

2-bit images are typically called bitmaps, and they contain only two colors – black or white. This is because the pixel is either turned on or off. For the most part, 2-bit images aren’t used much anymore, but when they are, it’s usually a case of a solid black piece of artwork (such as a logo) that will be colored in a layout program like Quark XPress or Adobe InDesign.

2-bit images can be used to enhance an 8-bit image, or used by itself simply as a graphical element in your design

8-Bit

With the exception of some high-end photographers, 8-bit is the most popular bit depth to work in because it provides 16.7 million available colors – which is far more than any human can see. And quite frankly, no inkjet or commercial printer can produce anyway. In 8-bit mode, you can use all the features available in Photoshop.

16 and 32-bit

Photographers typically shoot in camera RAW mode, offering them a higher bit depth. This essentially offers more color information to be stored in the pixels; so when they go into the RAW editor, they have much more flexibility in bringing out the detail in shadows and highlights. The problem with working in 16 and 32-bit images is that you have a very limited set of filters that will work above 8-bit.

In general, you shouldn’t have the need to ever work in anything but 8-bit. But I certainly encourage you to explore color correcting RAW images, and playing with the effect you can achieve using a 2-bit image.