Digital BW, The Print

Hi All;

Here are some further observations and tests (confusion?) on the BO 
workflow:

1)	A quick note on dot size: if your head isn't aligned 
perfectly, leaving the `high speed' on will make your prints look 
much grittier- test, align it if it needs it, or turn it off. It 
makes no difference on the density/contrast of the print. Also, for 
those of you who can do 2880 (and have the proverbial patience of a 
saint), that setting produces a much smoother, almost grainless 
print. I would suggest trying it after getting the process working 
at 1440.
2)	There are several ways to control output and the final 
print; these tests eliminate a couple so we can figure out what the 
others do. So the printer driver controls remain zeroed-out, printer 
gamma is left at 2.2, and PS density-contrast controls are not used 
to affect the output. The remaining controls I'm trying to 
understand are the `embedded profiles' (controllable from 
the `assign profiles' box in the `image>mode' menu) printer 
profiles, (controllable from the `print space' drop-down menu in 
the `color management' section of the PS print dialogue box) and the 
interaction of the two. 
3)	I went through a 15-print matrix: 3 with embedded profiles 
only and no printer profile, 3 with printer profiles but no embedded 
profiles, and 9 combinations of the two. In each case I used the dot-
gain 10%, 15% and 20% profiles.


First test sequence was with embedded profiles but no printer 
profile, and includes Clayton's settings, which as he said is near-
wyswig, but in fact prints a bit light; I was hoping to get closer 
without having to tweak the image itself. 

So this is a summary of the results:

Using embedded profiles only, going down from 20% to 15% and 10% 
LIGHTENS the image progressively about a half-stop each time. 
Conversely going up to 25% and 30% darkens it, though the effect 
seems a bit less pronounced, probably because in per-cent terms it 
is less of a change.

Using the printer profiles and no embedded profile does exactly the 
opposite: lower numbers give a darker print.

The combination of the two was fairly predictable: if you start with 
any given printer profile and go up the scale with the embedded 
numbers, the print gets darker. Start with any given embedded 
profile and go down the scale with the printer profiles, the print 
gets darker. And vice versa.

In the end, when I tested a new image that had not been adjusted for 
printing BO, I remained frustrated with this group of numbers- the 
darkest combination, 10% printer and 20% embedded profiles, was 
still a little weak. I didn't get full wysiwyg until I interpolated 
a bit and tried a 10% printer and 25% embedded profile. That 
produced a print of good contrast & density that looked very much 
like my monitor image before assigning the 25% embedded profile-the 
monitor image changes. I do that step last, and then undo it to 
compare the final print, on the theory that since dot-gain 20% is 
the default pre-press standard, I should stay centered around it. 

Subsequent test prints indicate that most images will print well at 
the 10%printer/25% embedded setting-but images that have a lot of 
very low-key important detail need the slightly brighter 10%-20% 
setting.
So, the settings that seem to work for me are as follows:
Printer: Black only, 1440 DPI, Gamma 2.2, high speed off unless your 
head is aligned really well.
Image in Greyscale, with an embedded profile of dot-gain 20% or 25%.
Color management on, with a dot-gain 10% as a printer profile.

The points to remember are as follows: Increasing the dot-gain% for 
the embedded profile darkens the image, decreasing it lightens it. 
Increasing dot-gain% in the printer profile does the opposite-
lightens the image, while decreasing it darkens it. Also: changing 
the embedded profile is I believe, the same as doing a tone-density 
edit, so don't save an image you've done that to unless it's a copy, 
and don't change the same image more than once, start with a fresh 
copy. 

Your mileage may vary, but I hope this gives anyone interested a 
basis for finding a workable combination of settings. 

My next project is going to be trying to make a six ink printer 
behave like a four ink printer by replacing two of the inks with 
clear base stock. Does anybody have any 
experience/opinions/suggestions that might be helpful?

Steve K