Types Of Inks...Which To Use

A fellow artists wrote me asking for information on the paint printing process that I've mentioned in previous posts, and her email brought to my attention how little I do know about the printing process in regards to inks. Here's a bit of info I found (at oddparts.com) while trying to educate myself. And you can go here to read about archival inks.

What is the difference between standard dye-based ink and pigmented ink?

1. Water Resistance

   • The dye in the dye-based ink dissolves in water like sugar does in water -- completely.
   • Pigment does not dissolve completely. It is more like a flour and water mixture.
   • Because of this, dye-based inks flow better and have been the standard in inkjet printers. But the dye will re-dissolve and the ink will flow across the paper if drops of water hit the paper.
   • Pigmented ink particles tend to settle into the tiny fibers that make up the paper. As the ink drys, the pigment particles get stuck in the fibers. Thus, the pigmented inks are more water resistent than the dye-based inks. Only about 5 to 10 percent of the ink will re-flow if the paper is hit by water.

2. Fade Resistance

   • The molecules in dye-based inks are spread out. You might think of dye-based ink on paper as similar to a beach covered with sand. Because of this, dye-based ink tends to fade quicker, since all of the molecules are exposed to the chemical and sunlight-caused reactions that fade the ink. You may notice fading of dye-based inks exposed to direct sunlight commonly in 6 to 12 weeks, although when protected from air and sunlight, these inks can last several years. However, new dyes developed originally by HP, Fuji, and Epson have improved the fade resistance of dye-based inks to be equivalent to the capability of most pigments.
   • Pigment particles are similar to large pebbles on a beach. It is much more difficult for sunlight and chemicals to react with all of the pigment molecules, since most of them are hidden inside the "pebbles". Pigmented inks will usually last for several months before fading becomes noticeable, and when protected from air and sunlight, these inks can last for many years.
   • Special Pigmented inks are those which are rated as "Archival Quality" Archival quality pigmented inks use special pigments to improve the fade performance beyond that of normal pigmented inks. Fading becomes noticeable when exposed to direct sunlight in 6-12 months, and when protected from air and sunlight these inks will last for decades.
   • For extremely long archival conditions, the best thing to do is simply to enclose a CD with the document or photographs. That way, if there is any damage down the road, the customer can simply reprint the material.

3. Print Quality

   • It is possible to get more "color" into dyes than into pigments. Therefore, dye-based colors tend to be more vibrant than pigment-based colors. And pigmented black inks tend to be slightly lighter than dye-based inks.
   • Dye-based black inks tend to be better for text printing, whereas pigmented black inks often are designed more to blend in a graphics application.
   • Photography usage depends upon the overall printer design. For example, HP uses pigmented black inks for normal printing, but their special photo cartridges have an additional dye-based photo black. Epson 6-color printers often use dye-based inks, whereas their 4-ink systems often use pigmented inks.
   • "Special Pigmented" inks have color vibrancy similar to that of dye-based inks, but there is still a difference noticeable to the professional.