<P> 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, making the ink less efficient and potentially allowing the ink to bleed at the edges of an image . </P> <P> 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 . </P> <P> An additional advantage of dye - based ink systems is that the dye molecules can interact with other ink ingredients, potentially allowing greater benefit as compared to pigmented inks from optical brighteners and color - enhancing agents designed to increase the intensity and appearance of dyes . </P> <P> A more recent development in dye - based inks are dyes that react with cellulose to permanently color the paper . Such inks are not affected by water, alcohol, and other solvents . As such, their use is recommended to prevent frauds that involve removing signatures, such as check washing . This kind of ink is most commonly found in gel inks and in certain fountain pen inks . </P>

Where does the ink from a pen come from