Digital BW, The Print

I haven't had enough time to keep up with all the posts so I'm a bit late.

Anyway, yes the uneven steps are the culprit.  It wasn't intended to handle
uneven steps but in the 2.3.1 version it turns out that it works in one 
direction -- B2A0 but not in A2B0.   This is obviously a nice feature and
so I've added this to the next version already.   I'm in the final testing of
2.3.2 and should have this available very soon.

Another comment that goes back to the original question about ICC profiles
versus Transfer Functions or .acv Adjustment curves.

In general they all have the same basic capability -- you can adjust the midtones
to where you want them between white & black.  However the chief benefit
of color management and icc profiles is that the curve is calculated at print
time to match up the file's profile and the printer's profile.  So instead of a
curve that only works for a specific grayscale such as GG 2.2 you can use any
file profile -- GG 1.8,  Dot Gain 25%, even Adobe RGB or sRGB.  Since this
whole color management is happening on your screen, it makes a lot of
sense for it to happen on printing too.

It has another very convenient feature in that the ICC curves are all applied in
16 bit mode and intelligently (dithering) converted back to 8 bit for printing.  
This is exactly like taking your data file, converting to 16 bit, applying your .acv
curve adjustments and then converting back to 8 bit. 

Roy


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" 
<paul.roark@v...> wrote:
>
> Carl,
> 
> Here it is.  I'll have more time to get to this later.  I don't know if it's
> the uneven steps, PC or what that is crushing the shadows.  For manual
> input, however, an uneven entry really helps.  The shadows are almost always
> were the action is.  I'll post the actual Lab L readings later. 
> 
> 
> File: C:\Documents and Settings\Paul Roark\Desktop\C86_G2_Con-10-out.txt
> Step	Dens	Lab	A	B	
> 0.00	0.034	97.00	0	0	-                             b
> L +
> 10.00	0.148	87.52	0	0	-                             b
> L       +
> 20.00	0.233	81.03	0	0	-                             b
> L           +
> 30.00	0.338	73.52	0	0	-                             b
> L               +
> 40.00	0.465	65.16	0	0	-                             b
> L                    +
> 50.00	0.599	57.24	0	0	-                             b   L
> +
> 60.00	0.783	47.62	0	0	-                           L b
> +
> 70.00	1.012	37.36	0	0	-                     L       b
> +
> 80.00	1.229	29.17	0	0	-                L            b
> +
> 85.00	1.340	25.49	0	0	-              L              b
> +
> 90.00	1.429	22.74	0	0	-            L                b
> +
> 95.00	1.519	20.15	0	0	-           L                 b
> +
> 96.00	1.534	19.74	0	0	-          L                  b
> +
> 97.00	1.542	19.51	0	0	-          L                  b
> +
> 98.00	1.572	18.71	0	0	-          L                  b
> +
> 99.00	1.574	18.66	0	0	-          L                  b
> +
> 100.00	1.607	17.80	0	0	-         L                   b
> +
> 
> Created ICC file C:\Documents and Settings\Paul
> Roark\Desktop\C86_G2_Con-10.icc
> 
> Paul
> www.PaulRoark.com 
> 
> _______________________________
> 
> > -----Original Message-----
> > From: DigitalBlackandWhiteThePrint@yahoogroups.com
> > [mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Carl
> > Schofield
> > Sent: Wednesday, October 19, 2005 11:54 AM
> > To: DigitalBlackandWhiteThePrint@yahoogroups.com
> > Subject: Re: [Digital BW] ICC v. Transfer Function in Epson driver
> > 
> > Paul,
> > 
> > I thought the steps had to be evenly spaced, but maybe not if you
> > were able to generate an icc profile.  Can you post the text file
> > that was generated when you made the icc profile?  I'm just wondering
> > how Create-icc  treated the uneven steps.  My experience has been
> > that the icc profiles improve shadow separation in 2400 ABW prints,
> > rather than compress the data.
> > 
> > Carl
> > 
> > On Oct 19, 2005, at 10:37 AM, Paul Roark wrote:
> > 
> > > Steve,
> > >
> > > I thought maybe my, in my view too-compressed, low values might
> > > just be an
> > > artifact of a bad un-adjusted distribution and too few points.  So,
> > > I tried
> > > the Create ICC and Print with Preview workflow with a printing
> > > setup that
> > > had a reasonably smooth low end.  I took readings at every 1% point
> > > between
> > > 100% and 95%, then at 5% to 80%, and then at 10% intervals.  I was
> > > also
> > > curious if the program needed even distributions of input data.
> > >
> > > The results were not much different than my previous attempts.
> > > Whereas the
> > > un-adjusted printing setup separated all the 95% - 100% points
> > > reasonably,
> > > the output adjusted with the Create ICC compressed the dark tones and
> > > posterized the 95% - 100% range.
> > >
> > > I don't know what caused this, but it's not, in my view, an output
> > > that
> > > efficiently utilizes the grayscale file information.
> > >
> > > Paul
> > > www.PaulRoark.com