QTR-Quadtone RIP

Printing the ink pattern in calibration mode to determine the ink limit 
(Epson 1400 Claria Black for BO at 2880dpi) I often get a reading with a 
shape like this:

   0  0.03
   5  1.08
  10  1.63
  15  2.00
  20  2.15
  25  2.22
  30  2.22
  35  2.21
  40  2.21
  45  2.21
  50  2.21
  55  2.22
  60  2.23
  65  2.23
  70  2.23
  75  2.22
  80  2.21
  85  2.21
  90  2.20
  95  2.20
100  2.21

What does one do in such a case?
- ink limit of 25 or 30, because D drops afterwards (although it gets to 
2.23 much later), or
- ink limit of 60 ?

Also: is it normal that I get a lower Dmax at 2880dpi (2.23) than at 
1440super (2.27)?

Thanks, Louis

Its effectively flat from 25, so I'd set the limit at 25 ... not that 
I'm an expert.

On 26/01/2011 23:07, Louis de Stoutz wrote:
>
> Printing the ink pattern in calibration mode to determine the ink limit
> (Epson 1400 Claria Black for BO at 2880dpi) I often get a reading with a
> shape like this:
> ....
> Thanks, Louis
>
> 
>

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[Non-text portions of this message have been removed]

Set the ink limit at 25.  Stay off the see-saw plateau.

Often I'll see the incremental increases get so low near the dmax that I set
it 5 or 10 below the actual dmax and set "boost" to the dmax.  So, for
example, it's possible the limit at 20 and boost to 30 and some further test
strips with a 30 ink limit might get the information needed to see what that
final approach looks like.  With the numbers below, I can't see if there is
a final 5 or 10 % or so that ought to be in boost.

The very steep final curve when boost is used helps at the edge of
the plateau sometimes.

You can fine tune the boost without messing up the rest of the profile also
(I think).  Each paper batch could be just a little different; nice to have
some wiggle room in the profile.

Paul
www.PaulRoark.com



On Wed, Jan 26, 2011 at 3:07 PM, Louis de Stoutz <loudest@...>wrote:

>
>
> Printing the ink pattern in calibration mode to determine the ink limit
> (Epson 1400 Claria Black for BO at 2880dpi) I often get a reading with a
> shape like this:
>
> 0 0.03
> 5 1.08
> 10 1.63
> 15 2.00
> 20 2.15
> 25 2.22
> 30 2.22
> 35 2.21
> 40 2.21
> 45 2.21
> 50 2.21
> 55 2.22
> 60 2.23
> 65 2.23
> 70 2.23
> 75 2.22
> 80 2.21
> 85 2.21
> 90 2.20
> 95 2.20
> 100 2.21
>
> What does one do in such a case?
> - ink limit of 25 or 30, because D drops afterwards (although it gets to
> 2.23 much later), or
> - ink limit of 60 ?
>
> Also: is it normal that I get a lower Dmax at 2880dpi (2.23) than at
> 1440super (2.27)?
>
> Thanks, Louis
>  
>


[Non-text portions of this message have been removed]

Thank you, Paul. I hadn't seen any use for the boost so far, but now I 
get it :-)
Going even slightly into the see-saw plateau, which I tried a couple of 
times, gave me rather strange values for the linearization.

A basic question about the linearized values:
Is linearization perceptive (for the eye)? Because when I measure it, I 
always get some kind of hanging curve, not straight.

Louis

On 27.01.2011 00:53, Paul Roark wrote:
> Set the ink limit at 25.  Stay off the see-saw plateau.
>
> Often I'll see the incremental increases get so low near the dmax that I set
> it 5 or 10 below the actual dmax and set "boost" to the dmax.  So, for
> example, it's possible the limit at 20 and boost to 30 and some further test
> strips with a 30 ink limit might get the information needed to see what that
> final approach looks like.  With the numbers below, I can't see if there is
> a final 5 or 10 % or so that ought to be in boost.
>
> The very steep final curve when boost is used helps at the edge of
> the plateau sometimes.
>
> You can fine tune the boost without messing up the rest of the profile also
> (I think).  Each paper batch could be just a little different; nice to have
> some wiggle room in the profile.
>
> Paul
> www.PaulRoark.com