A cartridge test standard? I guess this is just a general interest story for those interested in how much ink is really in a printer cartridge. Why is this important? Because it leads directly to the eternal question, “how many pages can I print with my cartridge?” which then determines how often you will have to buy printer cartridges, and how much it will cost to keep your printer full of ink.

As of now, it is up to manufacturer to disclose the amount of ink, usually number of milliliters (ml), that is inside a cartridge. The manufacturer then takes this number and uses a “magic” algorithm to determine how many pages of print you will get out of the cartridge. Most interesting is that these calculations are always based on 5% page coverage. So, here’s some quick math for you:

If you figure that a standard page is 8.5 x 11 inches, a single page will give you 93.5 square inches of paper to print on. Five percent of 93.5 is about 4.7 square inches. Now measure out a space that is 4.7 square inches on your piece of paper. If you print in that area only you should be able to print the number of pages the cartridge manufacturer suggests you can. Not likely, huh? (DISCLAIMER: I am not a mathematician, so if my math is wrong please correct me).

Back in February, the International Organization for Standardization (ISO) published a standard for measuring the number of pages an ink cartridge will produce. The standard was subsequently backed by HP, Canon, and Kodak. Standard ISO/IEC 24711:2006, which has yet to be approved, establishes how ink and toner cartridges are to be tested. The standard cites how many cartridges must be tested to determine an average lifetime (nine of them), what constitutes a standard test document (five pages printed with default printer settings) and the kind of machine on which the cartridge must be tested.

An interesting aside to the story, Kodak (a supported of this standard) has just released its own line of inkjet printers and inkjet printer cartridges and claims that they will be selling their printer cartridges at a price that is 50% less than other printer cartridge manufacturers. But, Kodak has yet to disclose how many milliliters of ink are in their cartridges. Until we know how much ink is inside one of their cartridges, we can’t really believe their price claim of 50% less.

We’ll keep you posted as we find out more.