QTR-Quadtone RIP

Hi Paolo

MIS sell a lot of inks so I'm still not sure what inks you have in which 
positions. You have Eboni black in the K position with, it appears from 
the qidf file, 5 further grey inks (at vastly different limits) in a 
hextone partition where the darkest grey is in the M position followed 
by successively lighter greys in the C, LM, LC & Y positions. Is that 
correct? Which MIS set is that? (MIS do sell UT-RC inks for the R260 but 
the arrangement you have here would not be appropriate for that as it is 
a tritone set with duplicate inks in the C & M positions and in the 
LM,LC & Y positions.)

LIMIT_K=30
LIMIT_C=25
LIMIT_M=75
LIMIT_Y=5
LIMIT_LC=12
LIMIT_LM=25
N_OF_GRAY_PARTS=6
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=M
GRAY_VAL_2=38,33
GRAY_INK_3=C
GRAY_VAL_3=29
GRAY_INK_4=LM
GRAY_VAL_4=16,66
GRAY_INK_5=LC
GRAY_VAL_5=11
GRAY_INK_6=Y
GRAY_VAL_6=5,66

How did you arrive at these limits? The Magenta position sticks out as 
being much highter than the rest & it might be that that should be 
reduced but without knowing what inks you have it is difficult to say 
for certain.

One further question - are you printing at 1440 or 2880dpi? At 2880 a 
limit of 75 would probably be too much for EAM.

regards
Howard

paolovertullo wrote:
> morning Howard,
> yesterday night i made same tests and you are right. 
> I added an overlap and it was much better but there is an overinking
> problem. The magenta ink arrives to his darker grey after starting to
> overload the paper.
> have i to use magenta in a range where it doesn't overink ?
> I use MIS ink with ebony black with an Epson R265 (european version
> for the r260) and Epson Archive Matte paper.
> 
> thanks
> Paolo
> 
> --- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:
>>
>> Paolo
>> 
>> What inks are you using here? The ink limits vary widely and this is
> not 
>> like any partition I have seen before. If I was to guess at the
> cause of 
>> the problem I would say that, upto the 98% spot, the magenta position 
>> ink in combination with the black ink is overinking the paper reducing 
>> dmax. Because you have no overlap the black is on its own at the 100% 
>> step and you're dmax is therefore restored (with an overlap the magenta 
>> would still fire at the 100% point). You could test this by adding an 
>> overlap of say 8. If I am right this will reduce the reading at 100% 
>> more in line with that at 98%. However this test is only confirming the 
>> problem - overinking - which still needs to be resolved.
>> 
>> (I've also not seen the use of commas as decimal places in qidf files 
>> before but I guess you would be having greater problems if these were 
>> not allowed).
>> 
>> regards
>> Howard
>> 
>