Some manufacturers (especially Canon) use different grades or types of ink depending on the task for which the ink is intended. This can cause confusion when two very similar cartridges are used in the same printer but for different tasks. A good example of the is is Canon’s use of CLI and PGI black ink cartridges. Some printers require both of these black cartridges in order to print text and images but the cartridges are not interchangeable. PGI is a Pigment based ink that is used for printing text while the CLI is a Chromalife ink that is used for printing photos. The CLI Chromalife ink is more resistant to fading when used with Canon photo paper and produces finer detail.