Continuous Ink Systems (CIS) are after market inkjet cartridge replacements consisting of ink cartridges that have never empty chip sets, 3.4oz / 100ml or larger ink storage bottles, and tubing that feeds the ink from the storage tanks into the cartridges. http://en.wikipedia.org/wiki/Continuous_Ink_Supply_System. CIS are marketed primarily to professional and advanced amateur photographers because superior photo quality inks can be used. However, any large volume inkjet printer user can benefit from the use of a CIS. Employing a CIS will save the pro / am photographer approximately 80% or more of photo printing ink costs while producing a better print. http://www.inkrepublic.com/members/ink.asp?Item=R800-P100. http://www.brandonstaggs.com/epson-r200-continous-ink-system-review.html.

With the advent of three technologies there is a much easier, faster and better photo creating process that allows a photographer to turn vision into printed photos ready to sell. The three technologies are the personal computer, the CCD (charge-coupled device http://en.wikipedia.org/wiki/Charge-coupled_device) and the inkjet photo quality printer. Photographers can now proof their photos without spending great amounts of time and effort in a darkroom or loads of money at the photo lab. Inkjet photo quality printers have evolved to where today, given good photo quality paper and ink, they can produce prints that are superior to any prints produced in a traditional darkroom. Inkjet photo printer prints can last up to 200 years using pigment-based inks and 100 years using modern dye-based inks. See: "Today's Technology In Inkjet Printing" by Mike Stensvold, Outdoor Photography, July 2007, pg 73.

A digital single lens reflex camera (dSRL), a personal computer (PC), photo manipulating software, good photo quality paper and plenty of photo quality ink put down in an appropriate manner makes an excellent inkjet photo. See: "Today's Technology In Inkjet Printing" by Mike Stensvold, Outdoor Photography, July 2007, pg 73. However, today's inkjet cartridges are expensive. A single color UltraChrome™ Hi-Gloss ink cartridge for the Epson Stylus Photo R1800 Printer costs $14.25 plus tax and shipping. http://www.epson.com/cgi-bin/Store/BuyInkResults.jsp?BV_UseBVCookie=yes&oid=53540919. Inkjet cartridges generally hold approximately 10ml to 12ml of ink. http://www.marrutt.com/lyson-contin.php That is approximately $1.30 per ml of ink. The more ink that any printer can put on the paper the better. Depending on the size of the ink droplet the human eye can perceive about 1,440 or less individual dots of ink. See: "Epson™ Stylus 1400" by Harlon Mitchell, Outdoor Photography, July 2007, pg 86. Ink droplets are measured in picoliters (one-trillionth of a liter). Given that some of the current inkjet photo printers are capable of utilizing ink droplets as small as 1 picoliter many ink droplets must be sprayed onto the photo paper in order to make the human eye believe that the photo is a continuous flow of color. A solution to the high cost of inkjet photo printing is to employ a bulk ink feeding system.

Most of the CIS use 3.4oz (100ml) or 4oz (125ml) and larger bottles of ink. For example, the Lyson™ 125ml Epson™ inkjet refills bottles are equal to approximately 10 traditional ink cartridges. http://www.marrutt.com/lyson-contin.phpThe Lyson™ full set of Pigment Ink in 4oz Bottles for Epson R1800 Bulk Ink System, which includes 8 channels each in 125ml bottles . Yellow, Magenta, Cyan, Photo Black, Matt Black, Red, Blue, Glossy Optimizer Pigment based (CavePaint™) cost $200.00 or $20.00 per ink set of eight cartridges or $2.50 per cartridge plus shipping. http://www.continuousinksystemsusa.com/product/r1800inkc. Even expensive ink will save the user money when employing a CIS. http://www.apexinks.com/index.php

Determining the correct CIS can be a daunting task. CIS, quality inkjet photo paper, and good pigment inkjet photo ink are being featured on web sites specializing in printing supplies for the pro / am photographer. Even the most expensive ink will save the user money when employing a CIS. Buying your printing supplies directly from the suppliers can save the user 30% to 50% of photo printing expenses.

Some names being used for Continuous Ink Systems:
Continuous Ink System - CIS
Continuous Ink Supply System - CISS
Bulk Ink System
Refill Ink System
Continuous Refill Ink System
Self refilling Ink System