The Black-and-White page type displays one bit of data per pixel on the screen as either black or white.Also known as the data type, color model or image type, the page type specifies the number of colors image documents can have.
The factor that determines the color content of image documents is the number of data bits each picture element (pixel) is composed of. The formula for determining the color content of image documents is 2 to the power of the number of pixel bits.
Imaging ActiveX controls support the following page types:
Black-and-White (Bi-Level) The Black-and-White page type displays one bit of data per pixel on the screen as either black or white.
Gray-Scale There are two types of gray-scale images: Gray4 and Gray8.
Gray4 A Gray4 image uses 4 bits of data per pixel. Every pixel on the screen can be displayed in 16 shades of gray, giving the image much better clarity than black-and-white images.
Gray8 A Gray8 image uses 8 bits of data per pixel. Every pixel can be displayed with 256 shades of gray, producing better image clarity than Gray4. Gray8 images are particularly effective for storing pictures and photographs.
Palettized There are two types of palettized images: Palettized4 and Palettized8.
Palettized4 A Palettized4 image uses 4 bits of data per pixel to reference a palette of 16 RGB (Red, Green, Blue) colors. These images can use a custom palette only.
Palettized8 A Palettized8 image uses 8 bits of data per pixel to reference a palette of 256 RGB colors. These images can use either a custom or common palette.
True Color-BGR24 This type of image uses 24 bits of data per pixel (eight bits-per-pixel for each of the three primary colors Blue, Green, and Red). This translates to 256 shades of each primary color to provide up to 16 million colors for each image. To display BGR24 images, the monitor and controller must be capable of displaying at least 32,000 colors. The BGR24 page type is typically encountered in BMP files.
True Color-RGB24 An RGB24 image is the same as a BGR24 image, but with the colors (Red, Green, and Blue) in a different order.
Aesthetics aside, the most important consideration when selecting a page type is file size. The greater the number of composite bits in an image document's picture elements, the greater the memory and storage requirements. For example, image documents whose picture elements are composed of 24 bits require much more memory and storage space than do those whose picture elements are composed of one bit.