There are several types of inks and ink formulations when it comes to printing, but they all have the same general purpose; to deliver an image onto a piece of media passing through the printer. However, some ink cartridges will deliver superior results when printing text and others will yield better results when producing images and photographs. The differing results are caused by the variation of elements found in the ink mixtures. An ink cartridge contains a basic mixture of water, glycol (a carrying liquid), and dyes or pigments and are intended to be jetted or sprayed onto paper or media, eventually creating an image.
The main difference between photo inkjets and regular inkjets is the ability of photo ink formulations to provide lighter tones of each color, commonly being cyan, magenta, and black. A regular cartridge will dispense wider set ink droplets to give image colors a lighter look. However, this makes lighter colored printouts look grainy and even multi-colored when inspected closely. This is because regular ink mixtures can only dispatch color so lightly, being intended for brighter execution to give printouts more vibrancy.
Photograph inks, on the other hand, will produce much lighter tones, perfect for shading and coloring elements such as faces and skin tones that have light colors. Since these mixtures produce lighter color, the ink is not as widely dispersed and results in smoother printouts that can capture high levels of detail. Many photograph ink compositions also avoid pigmented colorants since they do not sit as well on coated media such as photo glossy paper. Ink formulations vary greatly depending on the machine being used, the frequency of ink being ejected, and depending on the type of printing the machine is intended for.
There are three basic ink compositions, that mostly all inks can be categorized into including Dye-Based Inks, Pigment-Based Inks, and Hybrid Inks. Dye-Based inks are composed of colorants dissolved in a liquid, such as water or glycol and have the most vivid and rich finishing results. Dye-Based inks also have a wide color gamut, providing colors unreachable by other mixtures and are compatible with a wide range of photograph papers. Unfortunately these ink mixtures do not last long and fade easily with light and become runny when moisture is added. In general, a dye-based ink formulation printout will last between 5 and 25 years depending on the surrounding environment.
Pigment-Based inks on the other hand, contain insoluble powder pigments that are suspended in the ink composition and do not dissolve into the solution like dye-based inks. These pigments are coated in a resin-like mixture making them much more stable and giving them resistances to fading or light. A pigment-based printout can last anywhere from 75 years to 150 years depending on how and where the printout was stored and displayed. However, pigment-based inks do not soak into media as readily and have a tougher time adhering to coated paper.
Hybrid inks are a mixture of dye-based inks and pigment-based inks, and are sometimes referred to as pigmented inks. Combining the longevity of pigment-based inks with vibrancy of dye-based inks, Hybrid inks can be used for a number of applications and often offer superior printing results. Hybrid inks are known as pigmented inks since they use dye-based colorants and pigmented particles together, modifying the benefits and weaknesses of each type. Pigmented inks will have a wider color gamut than pigment-based inks but will not last as long. Pigmented inks (or Hybrid inks) can last up to 75 years when kept in an archival environment, such as being behind glass in a picture frame.
Most inkjet printers and ink cartridges also contain conductive elements to help shepherd or guide the ink to the page, usually reducing the size of the droplet in the process, for higher resolution printouts with sharper definition. Both photo and regular ink cartridges can be found with these assisting elements. The most common element that helps to shape and delivery ink is the Piezoelectric crystals. When a small electrical current passes through a Piezo crystal, the element will rapidly change shape forcing the ink out of the printer nozzles. The reaction shapes and can reduce the ink droplet size while forcing the mixture out of the cartridge and onto the paper.
Ink cartridges have differing elements depending on the type of printout being created, which will enhance a project and the overall quality when using the right selection of inks. For example, when printing text documents, a matte black ink cartridge formulation such as the Epson T054820, will yield the best results since the ink has a softer look, making the text easier to read for long periods of time. Using a photo black ink cartridge on text document printing will result in overly shiny characters or grayish texts that do not read as well.