| --- Perhaps you could start by telling me what exactly an ink is? I mean, you
hear terms like dye base and pigment base. What do they mean? Takizawa: Well, inkjet printer inks are solutions consisting colorants solvents, additives,
and water. It's color components, of course, that produce the ink's color.
--- Well, that makes sense. Takizawa: Yes, but colors can be made basically in two ways. This is simplified, but one way
is to pound or grind colored stone or some other colored material into a powder, while the other way is
through chemical reactions caused by mixing various chemicals together.--- So, the former are pigment base, and the latter dye base, right? Takizawa: Well done! (laughs) And pigment-based colors tend to fade less than dye base.--- Why is that? Takizawa: Well, put very simply, colors fade as a result of damage caused by exposure to light
and air. The biggest cause is light, particularly ultraviolet light. Then there are acidic gases in the
air, such as ozone (O3), NOx and SOx, that also attack color, breaking down color-producing
components, and causing fading as a result. The particles of pigment-based inks are much bigger than those
of dyes−maybe 100 to 1,000 times the size, in the range of 0.1 micrometers. As such, even if their
surface is damaged, they're still OK inside, and retain their color for quite some time. The color particles
in dye-based inks are very much smaller and easily broken down, which means they lose their color easily.
So, in terms of color retention, pigment-based inks are preferable.
--- If that's the case, you could get over the fading problem just by using
pigment-based colors, couldn't you? Takizawa: The trouble is that pigment-based color particles don't allow light through due to
their size, and so you don't get the transparency or clarity. To create the kind of beautiful color that
we like to call "photo quality", you need a certain degree of transparency and glossiness, and
that's what makes dye-based colors with their vibrancy preferable.--- Yes, but you're selling pigment-based inks too, aren't you? Takizawa: For example, big posters for outdoor display are viewed only from a distance, and
durability is more important than picture quality, so in such cases, pigment-based colors are used. There
are also occasions, say if you're wanting prints with an artistic feel like a painting, when a flatter,
less glossy feel is actually preferable, and pigment-based inks might often produce better results in such
cases. In other words, choice depends on application.--- I see. So in the end, the main reason for preferring dye-based inks is the
photo quality they provide. |
