PPI (Pixels per Inch) are clearly defined color pixels (pixels) in a fixed grid. Each individual pixel can take color values from 1 bit (2 colors) to 48 bits (280 trillion colors) depending on the product (sensor / light source).
- Fixed size per pixel
- Area-filling color per pixel
- Any color value 1 - 48 bits
Use of the name ppi : all devices that can display many colors per pixel:
- Digital Cameras
- Monitors / Screens
Any color values pixels
Here a gray bar (gray pixel) with a digital camera recorded
It is thus not possible to display each ppi with a dpi.
DPI (dot per inch) or (dots per inch) are limited color points, usually from printers. The color points are thus directly dependent on the number of color sources of the devices used. A simple inkjet printer delivers 4-6 colors (known as ink cartridges) However, in contrast to the PPI, the color points can vary in size and thereby The Farcharakter in the color intensity influence.
- Different dot size
- Reduced number of base colors per dot (eg 4 -6 colors for printers)
- The PPI pixel colors must be generated by several DPI points
- A 1200 dpi printer with 6x6 matrix can only represent a 200 PPI pixel
Use: Usually only printers that have to deal with a few basic colors per point:
- Laser printers
- Inkjet printers
Here a 4-color printer CMY + Black
The colors can only be achieved by mixing the basic colors and by the size Of the dots (dot).
Here the same gray bars as in the example above, but printed. In the matrix 6x6 Dot's is represented by the different black spots of the Distant seen a gray generated.
The mixture of the primary colors C (cyan) M (manganese) Y (yellow) and K for key (black fraction)