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But few people-including those in advertising and the sign industry-know anything about the history of ink.

All ink is used for the same basic task-coloring. Marking, writing, pigmenting, or filling space between the lines are all uses of ink, but the same type of ink cannot be used for each job.

Ink is an evolving substance. It differs in content geographically and comes with a range of textures and capabilities.

There is India ink, Chinese ink, and Sepia ink. Some ink is thin and watery. Other types of ink-such as the type used for screen-printing-are thick.

However, all types of ink have the same two parts-a vehicle and a colorant. Ink was first made by the Egyptians and the Chinese. At the birth of this color-giving liquid, the first inks were glues or gums were used as the vehicles and fine particles of carbon were used for colorant. The particles of carbon were called lampblack.

As ink making developed as a practice and then developed into a necessity, water and oil were also employed as vehicles.

Iron-gall ink wrote itself into ink's history in the eleventh century. Made from tannic acid and iron salt, iron-gall ink was used as a colorant. Resins were also occasionally added as binders.

Innovations in ink production have tackled problems such as durability, absorption to paper and other surfaces, and light-fastness.

To conquer these usage problems, the production of ink has become a complex process.

To really know ink and its history, one would need a thorough knowledge of the composition and functioning of the ingredients used to make ink. In addition, one would need to have a comprehensive understanding of the chemicals used in the manufacturing of it.

Over the years, preservatives and other chemicals have been added to ink to improve its overall quality, its durability, and its absorption rate.

For example, humectants may be found in any water-based ink. It is included in the chemical composition of ink to prevent early drying.

Water-based ink also often contains a small amount of biocide to keep the fluid at the proper consistency. To keep the pH level, buffering agents are sometimes added.

Because ink has become so specialized, the formula of ink must be such so that it is compatible with the type of tool or machinery using it.

Inkjet ink, for instance, must be made with materials that won't cause any wear or damage on the fragile print heads of computer printers. Since many inkjet printers are so sensitive, many different formulas for ink have had to be developed.

There are almost as many printer inks as there are types of printers. The advantage of such a diversity in ink material is that the required research and development has produced more sophisticated printing systems.

Inkjet inks are either water-based or solvent-based. The inks that were formerly colored with dyes have been blotted out in favor of the use of pigments as the colorants. This development in ink was not easily achieved.

However, this pigmentation technique has resulted in a variety of inks that are durable in the outdoors and have resulted in light-fast inkjet prints.

These days in the sign business ink is replacing dyes.

The main dilemma in replacing dyes with pigments was size. Inkjet orifices and portals are miniscule. They range from ten to twenty microns. A micron measures as one thousandth of a millimeter.

In order for this pigmentation to work in an inkjet printer, particle size had to be reduced in order for the pigments not to cause clogging in the machine.

Dyes are a solution and are smaller than pigments on the molecular level. Pigments are held in suspension and are considered a heterogeneous mixture.

However, dyes and pigments are derived from identical organic chemical compounds. This organic similarity results in dyes and pigments to be classified as dyestuffs.

The pigments in inkjet inks bear strong resemblance to those dye molecules used in dye-based inks. However, in the middle of ink production, the similarities of dye and pigments end.

Functional polar groups are used with dye molecules. This ingredient gives dyes the disintegrating quality that is necessary to dissolve in the vehicle. That is what makes that type of ink smaller than pigment ink.

Without these functional polar groups, pigments are completely insoluble in the vehicle and do not change from particle form.

To prevent the pigments from clustering, ink makers must add a dispersing agent to the mixture. The dispersing agent acts as a detergent.

Another complication in the use of pigment ink rather than the use of dye is that pigment is composed of several hundreds of thousands-and sometimes millions-of molecules.

A dye particle is a single molecule. This places the use of pigments as an important advantage. The many molecules of pigments help resist the deconstructing forces of ultraviolet light and the elements.

The single molecule of a dye particle can be demolished instantly and easily. Pigments have an inexhaustible amount of backups.

Although the chemical formula to this new type of ink involves more work in manufacturing, it opens up many doors in the world of inkjet printing. Developing inkjet ink is a boon for the sign industry.

Pigment ink can be applied to a wider variety of surfaces and will respond better to different temperatures, outdoor conditions, and fleeting time.

The sturdy composition of ink results in longer-lasting, better-looking graphics.