Digital BW, The Print

Roy wrote:
>
> For the future, I'd really like to get more precise control of the color
> and I think the two toner scheme is the best possibility.  I'm thinking of
> trying out the ultratone ink set but instead of the blue toner keeping the
> magenta and cyan inks separate and mixing them in software i.e. curves.
> That way I can vary the M/C mixture so the shadows have more M but the
> highlights stay more neutral.
>
> MIS just recently packaged a 2200 ink set where two toners are used but
> they are the blue toner and the sepia toner.  I suspect that will be used
> more as one or the other for a larger range of colors.  I know one guy
> trying this out on a 7500 as well.  For a 7 ink machine you could probably
> give up an other gray since they are variable dot size and add the
> yellow separate and get any tone you want.
>
Why not go the whole way with the hextone printers - using the UT inks.

Keep the three colours seperate, but add a little gray to them so that it
makes up for not having a light gray. In this way you can combine two
colours to get the tone you want. ( Y and m will give a sepia/brown
and m and c will provide a blue.)

16%  7600 Y   or   7600 M   or   7600 C
16%  7600 LK
68%  7600 Base
(NB - The base is the 7600 base which is a light tea colour - NOT the
colourless.)

Then I suggest using it as follows:

Position       Ink
K                UT-HEX-K  (Eboni)
C                UT-HEX-C   (dark gray)
M               UT-HEX-M   (middle gray)
Y (y?)         light yellow - from above
c                 light cyan - from above
m                light magenta - from above

In this way you can have any tone - period. I think the gray mixed in with
the colours would also tend to mask metamerism!?

Roy, can QTRip handle this without modification.

My teaching workload and my 1160 that stopped working kept me away
from working on QTR. I had Gimp-print 4.3.18 going under Linux and was
waiting for UT inks when my 1160 stopped. (The cost to fix it is more than
half the price of a new 1160.) Within the next two weeks I hope to get a
1290 and the I want to go to Gimp-print 4.3.21 to get the new improvements.
(See the attachment for the improvements that interest me.)

Reinier van der Ryst

  ----------

From: Reinier van der Ryst <rvdryst@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Subject: Re: [Digital BW] Re: MIS VM Sepia and QTR
Date: 30 October 2003 15:34

Roy wrote
> 
> For the future, I'd really like to get more precise control of the color
> and I think the two toner scheme is the best possibility.  I'm thinking of
> trying out the ultratone ink set but instead of the blue toner keeping the
> magenta and cyan inks separate and mixing them in software i.e. curves.
> That way I can vary the M/C mixture so the shadows have more M but the
> highlights stay more neutral.
> 
> MIS just recently packaged a 2200 ink set where two toners are used but
> they are the blue toner and the sepia toner.  I suspect that will be used
> more as one or the other for a larger range of colors.  I know one guy
> trying this out on a 7500 as well.  For a 7 ink machine you could probably
> give up an other gray since they are variable dot size and add the
> yellow separate and get any tone you want.
> 
Why not go the whole way with the hextone printers - using the UT inks.

Keep the three colours seperate, but add a little gray to them so that it
makes up for not having a light gray.

16%  7600 Y     /  7600 M     / 7600 C
16%  7600 LK
68%  7600 Base

Then use it as follows:

Position       Ink
K                UT-HEX-K  (Eboni)
C                UT-HEX-C
M               UT-HEX-M
Y                light yellow from above
c                 light cyan from above
m                light magenta from above

In this way you can have any tone - period. I think the gray mixed in with
the colours would also tend to mask metamerism!?

Roy, can QTRip handle this without modification.


Gimp-print 4.3.20
3) Ink drop sizes and densities have been recalibrated on many Epson
   printers, particularly the 4 picolitre drop size printers and the
   printers using DuraBrite ink (C80 and C82).  There proved to be
   significant errors in the drop sizes, making resolutions less than
   2880x720 produce inferior results.  In addition, many printers had
   incorrect density calibration at certain resolutions, generally
   producing output that is too light.

Gimp-print 4.3.21
1) This release offers further improvements in quality.  The specific
   improvements are described below.

   The driver now attempts to use as many small drops as possible
   before starting to use larger drops when printing on variable drop
   size printers.  This improves the texture of midtones, particularly
   at lower resolutions (extremely high resolutions typically only use
   the smallest drop size available).  The result is that 1440x720
   DPI, or in some cases even 720 DPI, now offers quality almost
   identical to higher (and slower) resolutions such as 2880x720 and
   2880x1440 DPI.

   The driver also uses more light ink prior to switching to dark ink
   (for 6 and 7 color printers).  This improves smoothness in
   midtones.  Furthermore, the transition between light and dark ink
   is adaptive, depending upon the amount of black (both black ink and
   black component printed with color inks) in addition to the color
   being printed.  This allows use of more dark ink in darker regions,
   reducing the likelihood of overloading the paper and producing a
   darker gray tone.  The combination of these two changes increases
   ink usage in some cases (mostly saturated midtones, where more
   light ink is used) and decreases it in others (mid grays).

   The color correction has been further tweaked based on observations
   of behavior in 4.3.20.  In particular, the desaturation in dark
   tones has been tweaked to achieve a better match and smoother
   transitions.

   The EvenTone dither algorithm has significant improvements in
   smoothness when multiple drop sizes are used, particularly for
   black-only prints.  In addition, certain artifacts in the light
   midtones have been eliminated.  There are some very weak new
   artifacts that may occur in regions of transition between drop
   sizes, but in most cases these will not be visible.

   Finally, the black generation has been changed, producing more
   solid dark tones.  Instead of a linear ramp between the point at
   black ink starts to be introduced and the point at which the gray
   component is printed with all black, the black generation now uses
   an exponential (gamma) curve whose exponent depends upon the
   printer and the paper in use.  This produces more solid dark grays
   while avoiding either a sharp transition from muddy grays using
   only color inks, excessive grain from use of too much black ink in
   lighter grays, or lack of contrast in dark tones caused by too much
   black ink.

   At present, only the Epson driver utilizes these changes.

2) Individual Epson printers have been retuned, producing closer
   matches between different printers and papers.  Specific
   improvements:

   * The new Stylus Photo series (780, 785, 790, 810, 820, 830, 870,
     890, 895, 900, 915, 925, 935, 1270, 1280, and 1290) has improved
     dark tones without muddiness.  In addition, the drop sizes at 720
     and 1440x720 DPI have been recalibrated, producing much better
     results in the midtones at these resolutions.

     The color correction curves of these printers have also been
     recalibrated on a variety of papers, in particular producing
     better blue and red tones.

     These printers also benefit greatly from all of the improvements
     described above, and produce quality very close to photographic
     prints.

   * The Stylus C70/C80/C82/C84 densities have been recalibrated on a
     variety of papers, eliminating excessive ink usage on high
     quality papers.

   * The Stylus Photo 950 and 960 drop sizes have been recalibrated,
     improving results significantly at 1440x720 DPI and to a lesser
     extent at 720 DPI.  In addition, the color correction curves have
     been adjusted, particularly for blue hues.  These changes will
     benefit the equivalent Japanese market printers (PM-950C,
     PM-970C, and PM-980C) if the dark yellow ink is not used.

   * The Stylus Photo 2100 and 2200 have been recalibrated on a
     variety of papers, using both matte and photo black ink.  In
     addition, the color correction curves have been adjusted and
     should give excellent color reproduction, particularly on glossy
     papers.

     These improvements should apply to other printers using
     UltraChrome inks (Stylus Pro 7600 and 9600).

   * The Stylus Color 680/777 ink drop sizes at 720 DPI have been
     adjusted.




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