On Mon, 19 Jul 2010 11:17:17 -0400, EXT wrote:

"harry" wrote in message
news:e560d5dc-9812-464d-acfb-
...
On Jul 18, 7:22 pm, Smitty Two wrote:
In article ,
"Ed Pawlowski" wrote:

"harry" wrote

You will not get black. That's why there's a separate black
cartridge.

It was not always like that. Check out an HP500C printer that had
only one
cartridge. It was not a true black, but "close enough" for most
people.

It's the difference between theory and practice. Nevertheless, the OP
is trying to forge black from what he has available. Equal proportions
are his best/only option and he gets what he gets.

No-one has been able to come up with the absolutely true RYB colour
pigments. That's why when you mix them you will only ever be able to
get a mucky brown at best. Nowhere near black. It all stems from the
subtractive and additive colour combinations. Also what pigments can be
manufactured.

That is why lithographic printing also uses four colors for color
photographs in newspapers, magazines and books. Years ago they tried
three color printing but the results were never good, and only used in
some newspapers because they didn't have the printing capability for 4
colors. Coffee table books often use a 6 color process to enhance the
color because even the 4 color process cannot reproduce all colors
accurately.

My old Canon Bubble-Jet printer, one of the first color consumer ink
printers had 4 colors and could print black pretty decent. Sharp's new
LCD TV the Quadra or something like that, uses 4 colors over the
traditional RGB scheme.