QTR-Quadtone RIP

GRAY_OVERLAP=percent

With this setting is the grey ink applied first, so that all of the black ink is applied OVER all of 
the grey ink,  or are the grey and black dots put down sporadically so they are "mixed"?  
Perhaps this differs by printer.  I'm on a 7800 with K3 if that helps.

Is anyone using this setting, or is it outdated and a holdover from older inksets?

Thanks.

Josh

--- In QuadtoneRIP@yahoogroups.com, "joshhackney" <joshhackney@g...> wrote:
>
> 
> 
> GRAY_OVERLAP=percent
> 
> With this setting is the grey ink applied first, so that all of the black ink is applied OVER 
all of 
> the grey ink,  or are the grey and black dots put down sporadically so they are "mixed"?  
> Perhaps this differs by printer.  I'm on a 7800 with K3 if that helps.
> 
> Is anyone using this setting, or is it outdated and a holdover from older inksets?
> 
> Thanks.
> 
> Josh
>

There's no way to really tell for sure -- al least there's no way to control it.
But given the weaving that is used I'd guess they are mixed randomly.
I think an overlap in the 10 to 20% range is usually good.

Roy

--- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" <roy@h...> wrote:
>
> --- In QuadtoneRIP@yahoogroups.com, "joshhackney" <joshhackney@g...>
wrote:
> >
> > GRAY_OVERLAP=percent
> > 
> > With this setting is the grey ink applied first, so that all of
the black ink is applied OVER 
> all of 
> > the grey ink,  or are the grey and black dots put down
sporadically so they are "mixed"?  
> > Perhaps this differs by printer.  I'm on a 7800 with K3 if that helps.
> > 
> > Is anyone using this setting, or is it outdated and a holdover
from older inksets?
> 
> There's no way to really tell for sure -- al least there's no way to
control it.

Actually, there is. The GIMPprint driver will interleave dots until
the dither pattent is full, only then will it start overlapping. There
is no laydown order control, the laydown will be, essentially, random,
sometimes lighter colors will be on top, sometimes darker ones.

If you tell the driver that the inks are different strengths of the
same color, the interleave will be more intelligent, i.e. it will
never overlay light colors when a single layer of a darker one is
availiable. 

> But given the weaving that is used I'd guess they are mixed randomly.
> I think an overlap in the 10 to 20% range is usually good.

The better the assignment of densities of the lighter inks relative to
the darkest, the smaller the overlap needs to be for good results.

Dear Roy and Koloshor,

Thanks for your replies.

Koloshor, I've re-read your post several times.  You wrote "If you tell the driver that the 
inks are different strengths of the same color, the interleave will be more intelligent, i.e. it 
will never overlay light colors when a single layer of a darker one is available."  With QTR, I 
have essentially told the drive that the inks are different strengths of the same color.  
Therefore, are you saying that the first layer of ink will be mixed LK and K, but that the 
driver will only apply K for the second layer?

On a seperate, but similiar topic, I have read on one of these forums that you should not 
use bi-directional printing, because the ink will be laid down in different orders depending 
on which direction the head is traveling.  From your comments, it sounds as though the 
dot pattern is totally random anyway, so the only concern with bi-directional printing is 
registration.  Is the a fair assesment?  Any thoughts on registration with a 7800?

Thanks for your help.

Best.

Josh

--- In QuadtoneRIP@yahoogroups.com, "koloshor" <koloshor@y...> wrote:

>
> --- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" <roy@h...> wrote:
> >
> > --- In QuadtoneRIP@yahoogroups.com, "joshhackney" <joshhackney@g...>
> wrote:
> > >
> > > GRAY_OVERLAP=percent
> > > 
> > > With this setting is the grey ink applied first, so that all of
> the black ink is applied OVER 
> > all of 
> > > the grey ink,  or are the grey and black dots put down
> sporadically so they are "mixed"?  
> > > Perhaps this differs by printer.  I'm on a 7800 with K3 if that helps.
> > > 
> > > Is anyone using this setting, or is it outdated and a holdover
> from older inksets?
> > 
> > There's no way to really tell for sure -- al least there's no way to
> control it.
> 
> Actually, there is. The GIMPprint driver will interleave dots until
> the dither pattent is full, only then will it start overlapping. There
> is no laydown order control, the laydown will be, essentially, random,
> sometimes lighter colors will be on top, sometimes darker ones.
> 
> If you tell the driver that the inks are different strengths of the
> same color, the interleave will be more intelligent, i.e. it will
> never overlay light colors when a single layer of a darker one is
> availiable. 
> 
> > But given the weaving that is used I'd guess they are mixed randomly.
> > I think an overlap in the 10 to 20% range is usually good.
> 
> The better the assignment of densities of the lighter inks relative to
> the darkest, the smaller the overlap needs to be for good results.
>