Digital BW, The Print

I've been asking about this in the QuadtoneRIP group but no answers. :-(

I'm trying to get a good profile for Harman Gloss FB Al on my Epson 4800.  I have noticed some odd things about existing profiles.

1 (major!):  Existing profiles for some printers seem to have density values, in ascending order, in the LINEARIZE= line (see for example the Epson 4000 or 2200 profiles).  But for the 4800-7800-9600 all existing profiles seem to have Lab values, in descending order, in the LINEARIZE= line.

Which is correct?  Does QTR automatically detect either?  SpyderPrint wants to emit density values when in "QTR" output mode.

2: I can't find any good documentation of what the BOOST_K option does or when or whether to use it.  I notice I'm getting maximum densities of about 2 while others report Dmax for this paper around 2.3.   I have DEFAULT_INK_LIMIT set to 60 which is if anything generous given the way the original calibration page printed.  Do I need to use a higher LIMIT_K or use BOOST_K to get the kind of Dmax others are seeing?

3: The 4800-7800-9600 profiles don't seem to use UC_NEUTRALIZER=yes.  Other profiles for other printers using Ultrachrome inks do so.  Is there a reason?

Thanks in advance to anyone who will tackle any of these.  The first one is the most baffling to me. :-/

Thor

"t_j_l_s" <tls@...> wrote:
>
> I've been asking about this in the QuadtoneRIP group but no answers. :-(

I put a link to a brief description of how I use the PrintFixPro spectro on the forum.  The workflow description is at http://www.paulroark.com/BW-Info/Spectro.pdf

>... SpyderPrint wants to emit density values when in 
> "QTR" output mode.

I don't use the "QTR" output mode.
 
> 2: I can't find any good documentation of what the BOOST_K 
> option does or when or whether to use it.

It puts a steep slope on the K curve from the other ink limit curve to the new K limit.  I find QTR's K curve usually has enough of a slope on it so the black boost is not needed.  It allows you to try a higher K limit, however, without messing up the rest of the profile.

> I notice I'm getting maximum densities of about 2 while 
> others report Dmax for this paper around 2.3.  

A quick way to find the best dmax is to print a 21-step test strip with a QTR profile that simply has a straight line from (0,0) to (100,100) for K, with all other inks not used.  To make the straight line curve, go to the Curve Creator, scroll down in the Black (K) box to Load Curve, then hit the Curve button.  Click on the Point List tab.  Then just enter the coordinates noted above.  The curve preview should show a straight line.  I name these curves "K-0-100." 

Hope this helps.

Paul
www.PaulRoark.com

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark" <pr_roark@...> wrote:
>
> "t_j_l_s" <tls@> wrote:
> >
> > I've been asking about this in the QuadtoneRIP group but no answers. :-(
> 
> I put a link to a brief description of how I use the PrintFixPro spectro on the forum.  The workflow description is at http://www.paulroark.com/BW-Info/Spectro.pdf

Thanks, Paul!
 
> >... SpyderPrint wants to emit density values when in 
> > "QTR" output mode.
> 
> I don't use the "QTR" output mode.

I can see easily enough how not to use it, as well  But that leaves one question remaining: whether QTR wants density or Lab values in the LINEARIZE= line of a profile.  I see some that ship with QTR which are done each way -- do you happen to know which is correct?

Thor

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "t_j_l_s" <tls@...> wrote:

> I can see easily enough how not to use it, as well  But that leaves one question
> remaining: whether QTR wants density or Lab values in the LINEARIZE= line of
>  a profile.  I see some that ship with QTR which are done each way -- do you
> happen to know which is correct?

Aha!  Roy answered me over in the other group:

> QTR handles either Lab or Density automatically.
> The values in the Linearize line should go from white to black:
> in lab that's big to small values
> in density its small to big values.

Thor

"t_j_l_s" <tls@...> wrote:

> Aha!  Roy answered me over in the other group:
> 
> > QTR handles either Lab or Density automatically.

> > The values in the Linearize line should go from white to black:

That's why I made a 21-step that has white on the left.  Most of use read from left to right.  This seemed to help people get them in the correct order.

Note that I put a little white mark on the left side of the spectro read orifice.  So, when I'm holding it in my right hand, I can use that white spot and the marks on the test strip (like this one -- http://www.paulroark.com/BW-Info/21-Step.jpg ) to be sure I've correctly centered the spectro over the test strip patch.

Paul
www.PaulRoark.com