Digital BW, The Print

Jeff,

Are you sure that the Epson driver with the Woolf workflow mixes all 
the inks equally? I would expect to see dots in the 0-20% range, 
which I don't? I haven't examined with it with a lupe, but to the 
naked eye I don't see any. Maybe it's just my old feable eyes! :-)

Would your method work equally as well with a CMYK setup. It seems 
like it would and it might give even more control - especially over 
the black?

I'll start with the Woolf lumped curve since that is what I'm 
familiar with at the moment and have done a lot of tweaking, but 
totally by eye. After that maybe the partitioned RGB or CMYK. I 
would really like to be able to control the 100-80% better than I 
can now. Al lthis is being done on a Epson 980.

Thanks again for your help,

Craig Spaulding

--- In DigitalBlackandWhiteThePrint@y..., "jrandall1149" 
<jrandall@c...> wrote:
> Craig:
> 
> The outlined method I posted is for creating a partitioned RGB 
curve 
> set (one that controls each of the three shade of gray 
seperately).  
> The Woolf workflow lumps all three gray inks into one, yielding a 
two 
> ink system (gray and black). Therefore no need to do Step 1.  Step 
4 
> would use the Brightness Curve function in HSV colorspace instead 
of 
> the Color Curve function.  ETC.
> 
> Another point about the Woolf workflow is that the color positions 
of 
> the gray inks don't matter, because they are all mixed in 
approximate 
> equal proportions by the Epson driver.  So this workflow (approach 
> not the exact curve) can work for MIS original, or MIS FS, or any 
> inkset with different ink positions or ink densities.
> 
> I suggest you read the both Woolf's and my workflow documents for 
> additional details.
> 
> Jeff Randall  
> 
> --- In DigitalBlackandWhiteThePrint@y..., "craig_spaulding" 
> <craig_spaulding@y...> wrote:
> > Jeff,
> > 
> > Wow, thanks for the details. This will keep me going for a 
while...
> > 
> > Craig Spaulding
> > 
> > --- In DigitalBlackandWhiteThePrint@y..., "jrandall1149" 
> > <jrandall@c...> wrote:
> > > --- In DigitalBlackandWhiteThePrint@y..., "craig_spaulding" 
> > > <craig_spaulding@y...> wrote:
> > > > Jeff,
> > > > 
> > > > I have several questions re your transfer curves technique:
> > > > 
> > > > 1) Can the black and white points be set in Photoshop 
instead 
> of 
> > > the 
> > > > scanner after the step-edge has been scanned? I work with a 
> > digital 
> > > > camera and my scanner is marginal and I don't think the 
black 
> > and 
> > > > white points can be set in the software.
> > > 
> > > I've had better luck setting the b/w points during scanning 
than 
> > > setting in my image editing software (your results may vary).  
I 
> > use 
> > > VueScan as my scanning software and have found the histogram 
> > feature 
> > > to be very good. (www.hamrick.com). I use Picture Windows as 
my 
> > image 
> > > editing software because I think its curves/histogram feature 
is 
> > the 
> > > best of any editing package (I also use it for a lot more 
> reasons, 
> > > but that's another post) (www.dl-c.com). I also have and 
> > occassionly 
> > > use PhotoShop 6.0 
> > > > 
> > > > 2) Is this a technique for making a transfer curve or a 
curve 
> > that 
> > > > is to be applied in an adjustment layer? Once the curve is 
> made, 
> > > can 
> > > > it be applied either place?
> > > 
> > > Transfer curve and adjustment layer curves are essentially the 
> > same.  
> > > They both map an input value (in what ever units) to an output 
> > > value.  Because they use different units they are not directly 
> > > interchangeable, but if you do the math you can create curves 
the 
> > do 
> > > the same thing in both worlds.
> > > > 
> > > > 3) Is there a good method for going about modifying an 
existing 
> > > > curve (like the Woolf)? Do you click on the appropriate step 
in 
> > the 
> > > > step-wedge to find out where it is on the curve that step 
is, 
> > then 
> > > > use the up/down arrow or change the numbers in the dialog 
box? 
> > If 
> > > > so, is there a rhyme or reason for how much to change it to 
> > equally 
> > > > space out the peaks, or, is it all trial and error. Or, do 
you 
> > just 
> > > > focus on changing the general shape of the curve to space 
out 
> > the 
> > > > peaks?
> > > >
> > > Here is an approach that I used to create my RGB Partitioned 
> > Workflow 
> > > for the 1160 and MIS FS inkset (and modify the Woolf lumped 
> > > workflow).  It works for me (your milage may vary)  It is not 
a 
> > > complete cookbook and every nuance is not spelled out.  
> > > 
> > > 1)  Print a quad purge image and scan using the procedure 
> outlined 
> > in 
> > > step #3 to determine the approximate reflective values (I use 
the 
> > 0-
> > > 100% scale) of each pure ink on the paper.   Crop the image to 
> > > produce approximately equal areas of the 4 inks and white 
space.  
> > The 
> > > ink values determine the maximum "density" that can be
> > > achieved by 
> > > each ink alone and serve as a guide to when the next darker 
shade 
> > > must be started. 
> > > 2)  Apply a starter RGB partitioned curve set to a 21-step 
wedge 
> > test 
> > > image and then print.
> > > [Note:  I use the step wedge posted in the Files section of 
the 
> > Yahoo 
> > > Piezography3000 Group.  The file is piezmultisteps.psd.  It 
has 
> > > excellent low (95-100%), medium (45-55%), and high (0-5%) 
> > brightness 
> > > test areas to allow you to visually  evaluate and set these 
> > benchmark 
> > > values. I initially used Paul Roark's curves he developed for 
the 
> > > Piezography BW inkset and the Epson driver.]
> > > 3)  I scan the print with my HP-5370 scanner using VueScan.  
VS 
> > > settings are: 
> > > * Crop = tightly set to only scan the narrow 21 step portion 
of 
> > the 
> > > test image. Don't include any of the grayscale ramp or the 
> portion 
> > of 
> > > the 21 stepwedge with the light or dark separator lines.  My 
goal 
> > is 
> > > to have 21 separate and narrow histogram peaks with little 
noise 
> > in 
> > > between.   
> > > * Color balance = auto levels. I use auto levels because it 
sets 
> > each 
> > > RGB curve to the b/w points — neutral doesn't and white 
balance 
> > > doesn't do this well.
> > > [Note:  I don't care about the "color" of my
> > > grayscale—all I'm 
> > > interested in is the overall/combined brightness.]
> > > * B/W points set to clip the 0% (255) and 100% (0) gray value 
> > steps 
> > > to expand the range to the maximum.  That is, set the 0% gray 
> > value 
> > > to the whiteness of my paper and the 100% gray value to the 
> > blackest 
> > > black I can print with the inkset. 
> > > * Scanning resolution = 150 dpi. 
> > > * Number of passes = 4.  This reduces noise and increases peak 
> > > separation, especially in the dark end.  The exact pixel 
> alignment 
> > is 
> > > not an issue with a stepwedge print.
> > > * File color space = AdobeRGB
> > > * Grain reduction = heavy.  This also seems to increase peak 
> > > separation in the dark end.
> > > * Tiff file type = 24-bit RGB
> > > 4) I open the Tiff file in Picture Windows and apply the 
> > Color|Curves 
> > > function which combines a curve and histogram view of the 
pixels. 
> > > [Note:  The PW Color Curve and grayscale Brightness Curve 
> > functions 
> > > can both display the image value, lightness, or brightness of 
the 
> > > image in the HSV, HSL or RGB color spaces, respectively.  I 
use 
> > the 
> > > HSV color space because it does a good job of separating the 
> image 
> > > brightness component from the color components which I don't 
care 
> > > about.  Image brightness in the RGB space is a weighted sum of 
> > each 
> > > RGB color and overall not as useful.]
> > > 5)  I note on a worksheet whether each of the remaining 19 
peaks 
> > > needs to be moved lighter or darker and a relative amount.
> > > 6)  I then load and apply the RGB partitioned curve used to 
> create 
> > > the tight crop of the 21 step wedge to my test image and 
adjust 
> > each 
> > > individual RGB curve (red=dark, green=medium, & blue=light 
gray), 
> > as 
> > > determined in Step #5. 
> > > 7) I then save the new RGB partitioned curve under a different 
> > name.
> > > [Note: When I get close to where I want the peaks to be, I 
open 
> > the 
> > > Picture Windows RGB partitioned curve file (filename.cc) with 
a 
> > text 
> > > editor and manually change the values (which are stored as 0-
255 
> > > values) ]
> > > 8)  I then print the test image.  
> > > 9)  Iterate until you are satisfied (or run out of paper or 
ink).