QTR-Quadtone RIP

Still further on this topic, I posted the following in two replies in the Digital Black & White forum (should have been here first I think since it is a QTR topic).

I re linearized David Goldenberg's IGFS profiles(QTR_1400_UT14_IGFS_warm and QTR_1400_UT14_IGFS_cool) for the Epson Prem Semi Gloss using an X-Rite 810. The plaque of the 810 gives a reading of 0.09 D on the white spot and 1.79 D on the black spot. These are the correct readings for this plaque's reflection standard. When reading "paper white" the 810 also reads 0.09 D, which is what I would expect.
 
These were the readings I got using the 810, QTR_1400_UT14_IGFS_cool and Epson Premium Semi Gloss paper.
 
 .09
 .15
 .20
 .25
 .29
 .33
 .38
 .43
 .47
 .50
 .52
 .58
 .65
 .73
 .81
 .90
 1.01
 1.19
 1.34
 1.53
 1.81
 
I then opened QTR_1400_UT14_IGFS_cool in Curve Creator, cleared  Liearization and entered these figures and saved it as QTR_1400_UT14_EPSG_cool.
 
Looking at the curve for the result it doesn't look very linear (David's curve for the IGFS is virtually a straight line).

Not satisfied with this I then printed a further 21step.tif with this file, remeasured the steps and entered these measurements into the Linearization Values of Curve Creator saving this as QTR_1400_UT14_EPSG_cool1. When I clicked on Show Curve, to my amazement I got a nearly straight line - just a slight wave in the middle. 

I did the same with QTR_1400_UT14_EPSG_warm and called it warm1 and got a good straight line, identical to David's QTR_1400_UT14_IGFS_warm. As this was a better curve than the QTR_1400_UT14_EPSG_cool1 I replaced the cool1 values with the warm1 values to produce the same straight curve and called it cool2.

If the object of the exercise is to produce a straight line "curve", have I, in using this method achieved the right result ?

--- In QuadtoneRIP@yahoogroups.com, "Mel" <chilterns@...> wrote:
>
> Further on this topic, I have printed off the 21step.tif using QTR_1400_UT14_IGFS_cool and a blend of QTR_1400_UT14_IGFS_warm and QTR_1400_UT14_IGFS_cool (75% cool and 25% warm and) and find bronzing on the black end of the step wedge. This is only on the 100% patch and only seems to be in daylight. None of the other patches are affected and it doesn't appear when viewed in artificial (incandescent) light. 
> 
> I also did the same using the same profiles with Epson Premium Semi Gloss paper, with the same result.
> 
> When using Epson Premium Semi Gloss paper with the Epson 1290 and the 1290 profiles with UT2 inks there was no bronzing - alas the 1290 "gave up the ghost" and is no more.
> 
> Is there a satisfactory explanation for this and/or could UT2 inks be used with the Epson 1400.
> 
> I favoured the Epson Premium Semi Gloss paper as it is a brighter white - the Ilford Gold Silk is a creamier paper.   
> 
> --- In QuadtoneRIP@yahoogroups.com, "David" <dpgoldenberg33@> wrote:
> >
> > No.  
> > 
> > The profiles do not include glop (in the "yellow" cartridge in UT-14), and there should be no need for spraying. (I've never actually tried it.) The profiles use the glossy-compatible photo-black ink and no ebony.
> > 
> > David
> > 
> > 
> > 
> > --- In QuadtoneRIP@yahoogroups.com, "Mel" <chilterns@> wrote:
> > >
> > > One for David (dpgoldenberg33) really
> > > 
> > > Does QTR_1400_UT14_IGFS_warm and QTR_1400_UT14_IGFS_cool, require "glop" or spray application ?
> > >
> >
>