QTR-Quadtone RIP

Hi Bill

The usual methodology is to regard the untoned curve you have already 
created as the "warm" curve and then create a "cool" curve. Once you 
have these, at the point of printing, you can use the Curve set up 
sliders to mix the two to produce a neutral that you are happy with.

To create a cool curve you will need to add some cyan and some magenta. 
There are a number of ways you can approach this. Perhaps the simplest 
is to use the 'Copy Curve from' option in the Ink Setup tab of the Curve 
Creation dialog.

There you can set the Magenta & Cyan inks to copy the LK curve and the 
LM & LC inks to copy the LLK curve. Restrict the ink limits to fractions 
of the LK & LKK curves. You will need to experiment with the limits 
until you are happy with the tone. Look at other cool curves made using 
OEM inks for examples.

There are other ways including using Toner 1 & Toner 2 as you suggested 
or the Load Curve facility but these are more complex (but are more 
fine-tuneable).

Howard

PS There can't be more than 2 Bill Brandt's so I think we know know each 
other!

etlblbt wrote:
> Thanks to everyone who replied.  I have access to a microscope so I 
> took a part of the print and examined it visually at a magnification 
> where I can see the individual ink dots.  I can see that all the dots 
> are grey and there are no other colours being laid down so my only 
> conclusion is that the grey inks are not truly neutral and do have a 
> warm tone to them (or there is some tone coming from the paper).
> 
> So now it looks like I am going to have to use the toning channels to 
> bring the print back to a true neutral.  Is there a good method for 
> establishing how to set the toning channels to achieve a neutral 
> print?  I have access to an eye-one.
> 
> Bill
> 
> --- In QuadtoneRIP@yahoogroups.com, "Michael King" <drmrking@...> 
> wrote:
>>
>> Also what your spectro reads is going to depend on the colour of 
> the paper
>> the inks are printed on.
>> 
>> On 18/10/2007, Michael King <drmrking@...> wrote:
>> >
>> > Isn't that because the blacks are not neutral. They are naturally 
> warm
>> > carbon?
>> >
>> > Mike
>> >
>> >
>> >  On 18/10/2007, etlblbt <bill.brandt@...> wrote:
>> > >
>> > >   Hello,
>> > > I have just started trying quadtone RIP and I have tried to make
>> > > my first profile for my EPSON R2400 which is loaded with the 
> standard
>> > > inkset. In the ink descriptor file I have set the density 
> values for
>> > > the light black and light light black inks (measured using a
>> > > spectrophotometer) and have set all the other inks to 'not 
> used'.
>> > >
>> > > When I print out a test strip (the 21x4 random) and analyse it 
> with my
>> > > spectrophotometer I can see that the colours are not neutral 
> (when
>> > > converted to RGB there is quite a lot less blue than the other 
> two
>> > > channels) and the print visually has a brownish tone.
>> > >
>> > > Is there something else I need to do to prevent the colour inks 
> from
>> > > being used other than setting them to 'not used' in the ink 
> descriptor
>> > > file.
>> > >
>> > > Apologies if this is all in a FAQ somewhere. If you could point 
> me to
>> > > it that would be great.
>> > >
>> > > Regards, Bill Brandt
>> > >
>> > > 
>> > >
>> >
>> >
>> 
>> 
>> [Non-text portions of this message have been removed]
>>
> 
> 
> 
> 
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