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A monochrome bitmap is a type of digital image that displays only a single color, usually black. This is a type of one particular file format, which is referred to as a bitmap (BMP), and is often used in the creation of simple graphics. In a bitmap, each pixel or “picture element” of an image is represented by a particular number of bits, which are units of information. A monochrome bitmap has pixels that are only one bit, allowing each pixel to either display a single color or no color, often seen as black and white.
There are a number of different reasons why someone might create a monochrome bitmap, though these images are all created using the same type of data. Most users of digital art programs do not necessarily interact with individual bits of data in their creations, but instead adjust settings in the software that impacts how these bits are used. A bitmap, which is a commonly used file format for digital images, is simply a type of image that is pixel-based. Pixels are individual components of an image, usually seen as tiny dots of pigment or light, similar to the points of color used in creating a painting through pointillism.
A bitmap image, such as a monochrome bitmap, is created in a way that assigns a number of different bits of data to each pixel in the image; this is referred to as the “bits per pixel” (BPP). The number of colors that can be displayed on a bitmap image is equal to two raised to the power of the BPP number for that particular file. An image that can be displayed in “256 color,” which means up to 256 different colors can be used, is an 8-bit image; eight bits are used to determine the color of each pixel which means that 28 or 256 colors are available.
Only a single bit of data is used for each pixel of a monochrome bitmap, meaning that these images have only 1 BPP. This means that such images can have 21 colors, or only two colors available. While technically it may be possible for someone to set these colors differently, a monochrome bitmap is typically created with one color being black, and the other is transparent. Since this transparent area is usually appears on computer screens and paper as white, these images are considered black and white.
Each bit used to create a monochrome bitmap is a piece of binary information, meaning that it is represented by either a one or zero. A pixel with a value of zero is usually displayed as transparent or white, while pixels with a value of one are black. These images have no possibility of other colors or values, so a monochrome bitmap displays crisp, straight horizontal and vertical lines, but curves and diagonal lines can appear more jagged.