There is a reason for the gloss optimizer. Epson's R800 uses pigmented
inks. The advantage of pigmented inks, as of right now, is that they
are more permanent and less likely to fade than dye inks. That may
change over the next year or two as new inks and papers hit the market.
The problem with pigments is they tend to dry a bit more matte than most
would like, even on glossy papers. And areas with high ink coverage
even on glossy paper, will show the ink as flat. It looks even worse if
you look at the image at an angle, with light reflecting on it. The
gloss optimizer coats the ink areas to make them as glossy as the areas
that are not covered in ink. The two blacks are because for matte
papers, a denser black is needed and it is usually very matte. Using a
second black which is more glossy, but less dense, works better on
glossy papers.

What the best ink color combinations are to give highest accuracy is
often in debate, and it does depend upon the type of inks (dye versus
pigment) and the type of color management and drivers used. With
pigmented inks, particularly, since they are not fully transparent,
mixing certain ink colors may not provide the purity of color that a dye
ink might. Mixing yellow and magenta pigmented inks may not make as
pure a red as a pure red pigment. Same with blue, which is normally
made from cyan and magenta inks.

In the case of dye inks, getting a good range of greens, especially
deeper forest greens, which require cyan, magenta, yellow and black in
varying amounts are tricky to get, so some manufacturers use green.
Some commercial ink sets add orange.

At the end, what colors are in the set is not really important to the
end user. It's sausage making. What you should care about is how good
the output looks, what variety of papers work with the inks, how much it
costs per print, how fast the printer is, how reliable the printer is,
and, if it matters to you, how long the print is likely to last.

Art




Rob wrote:

"Miss Perspicacia Tick" wrote:


Has anyone had experience of both? I notice (after reading a review) that
the 'R' series also has 8 colours, but has lost the PC and PM in favour of
an extra black, red and *blue* - and a 'gloss optimiser". The i9950 (which I
have) still has PC and PM and the addition of red and *green*. Every review
I've read has rated the Canon over the Epson (this was the i990 vs the
R800). Does blue make a difference to green and what does the 'gloss
optimiser' do? After all, if you want gloss you simply use glossy media,
surely?! Or am I missing something?




Yes you are dear.
Surely you wouldn't settle for just glossy when you could have
"glossier"? It's for those who feel absolutes won't do and would like
something stronger. Like Starbucks and the "grande" size which normal
people would call small but "small" sounds so, well, small.