Editing Ink (section)

== Types ==
[[File:Tintenstrich-detail 2.jpg|thumb|Magnified line drawn by a [[fountain pen]].]]

Ink formulas vary, but commonly involve two components:
* Colorants
* Vehicles (binders)

Inks generally fall into four classes:<ref name="kipphan130-144">{{Citation|last = Kipphan|first = Helmut|title = Handbook of print media: technologies and production methods|publisher = Springer|year = 2001|edition = Illustrated|pages = 130–144|url = https://books.google.com/books?id=VrdqBRgSKasC|isbn = 978-3-540-67326-2}}</ref>
* Aqueous
* Liquid
* Paste
* Powder

=== Colorants ===
==== Pigments ====
{{Main|Pigment}}
Pigment inks are used more frequently than dyes because they are more color-fast, but they are also more expensive, less consistent in color, and have less of a [[Gamut|color range]] than dyes.<ref name="kipphan130-144" />
Pigments are solid, opaque particles suspended in ink to provide color.<ref name="kipphan130-144" /> Pigment molecules typically link together in [[crystal]]line structures that are 0.1–2 [[Micrometre|μm]] in size and comprise 5–30 percent of the ink volume.<ref name="kipphan130-144" /> Qualities such as [[hue]], [[Saturation (color theory)|saturation]], and [[Lightness (color)|lightness]] vary depending on the source and type of pigment.Solvent-based inks are widely used for high-speed printing and applications that require quick drying times. And the inclusion of TiO2 powder provides superior coverage and vibrant colors.<ref>{{cite web|url=https://wotaichem.com/china-titanium-dioxide-tio2/ |title=Major Applications of Titanium Dioxide for Ink |publisher=Wotaichem |date= |access-date=2022-04-11}}</ref>

==== Dyes ====
{{main|Dye}}Dye-based inks are generally much stronger than pigment-based inks and can produce much more color of a given density per unit of mass. However, because dyes are dissolved in the liquid phase, they have a tendency to soak into paper, potentially allowing the ink to bleed at the edges of an image.

To circumvent this problem, dye-based inks are made with solvents that dry rapidly or are used with quick-drying methods of printing, such as blowing hot air on the fresh print. Other methods include harder [[paper]] [[sizing]] and more specialized paper coatings. The latter is particularly suited to inks used in non-industrial settings (which must conform to tighter toxicity and emission controls), such as [[inkjet printer]] inks. Another technique involves coating the paper with a charged coating. If the dye has the opposite charge, it is attracted to and retained by this coating, while the solvent soaks into the paper. [[Cellulose]], the wood-derived material most paper is made of, is naturally charged, and so a compound that complexes with both the dye and the paper's surface aids retention at the surface. Such a compound is commonly used in ink-jet printing inks.

An additional advantage of dye-based ink systems is that the dye [[molecule]]s can interact with other ink ingredients, potentially allowing greater benefit as compared to pigmented inks from [[optical brightener]]s and color-enhancing agents designed to increase the intensity and appearance of dyes.

Dye-based inks can be used for anti-counterfeit purposes and can be found in some gel inks, fountain pen inks, and inks used for paper currency.<ref name=":0" /> These inks react with cellulose to bring about a permanent color change.<ref name=":0">{{Cite web|title=Dyes, Pigments and Inks|url=https://www.acs.org/content/acs/en/careers/college-to-career/chemistry-careers/dyes-pigments-ink.html|website=American Chemical Society|language=en|access-date=2020-05-15}}</ref> Dye based inks are used to color hair.