Why are Epson inkjet printers so non-linear in raw mode?

[Greg]

I recall reading Bill Atkinson's report on what he had to go through to
create the ICC profiles for the Epson 7600/9600. One thing he mentioned was
that when the printer drivers are used in their "no colour adjustment" mode,
the response is very non-linear. I've certainly noticed this on my 1270, and
it seems that my new 2200 will behave the same, since it's similar in design
to the 7600 & 9600. I'm curious to know whether this non-linear behaviour is
by design, or is simply some kind of "laziness" on Epson's part. Can anyone
shed some light on this? (no pun intended!

I can't find the report at the moment - if it's still available, I'd
appreciate a pointer to it - thanks.

Greg.

 

[Greg]

Ah - I found the document - it's supplied with the profiles themselves. Doh.

http://www.epson.com.sg/html/body_icc_profiles.html

Bill writes:
"The 9600's native No Color Adjust mode is so far from linear and gray
balanced, that none of the profiling software could deliver accurate enough
neutrals." .............

Greg.

 

[Greg]

Yep - my 2200 certainly is very non-linear in no colour adjust mode.
Photoshop 7.01 can't even create a smooth curves correction for the green
channel - I'll need to use a seperate curve fitting program to create the
pre-linearisation curve for the green channel. In fact, the green response
is not even monotonic!!!