QTR-Quadtone RIP

So far, I've not had to create new curves, just tweak existing ones for 
similar papers. Now I've switched to an Epson 3880 and it doesn't have 
many existing papers to start from, so I'm trying to figure out how to 
create my own curves, starting with a glossy paper (innova fibaprint 
white gloss).
I've printed a 21 greyscale patch and read the Lab values, and am now 
not sure how to interpret them.

L I'm not bothered about ... linearising should clean that up easily 
(its pretty good to start with) but am not sure how to interpret the a 
and b values:

a starts from a low range of 0 to 0.4 (meandering) up to the 50% ink 
point, then rises steadily to 1.6 at 70% ink, and then to 1.8 at 90% ink.
b varies up and down over a range of 1.5 to 2.4 (the paper white is 
1.5). As there's not much of general progression, more meandering up and 
down, it seems I'll just have to take this as reasonable.

Being partially colour blind, its not easy for me to judge the impact! - 
are these significant (this is supposed to be the neutral curve) or 
should I try to at least reduce the a ramp, by reducing the magenta 
content a little

Thanks for any insight ...

mike

-- 
mike finley photography
http://www.mikefinley.co.uk