Digital BW, The Print

Hello jeades947,
 
>when I try this with my Canon S750 printer; I fail to get any 
>values above Zone 7 to have any body in them. They are all blank 
>white. 

Sorry for replying so late, I was gone all day yesterday.  I have an
idea to suggest, but first I must disagree with Charles' statement:

"Printing with black ink only is not a very good way to get 
grey tones..."

BO printing can produce beautiful gray tones.  Yes, it does it by
adjusting the spacing and dithering of the dots, and yes, at some
point as you approach white there are very few dots (and finally,
none), but this does not automatically mean there is a sudden fall off
from gray to white with no transition.  BO can render beautifully the
most subtle gradations, all the way across the scale.

I'm sure Charles believes what he's saying, so I can only assume he's
never seen a well done BO print, or perhaps his experience with them
was with earlier model printers.  Today's printers can produce
gorgeous BO results.  

>when I try this with my Canon S750 printer; I fail to get any 
>values above Zone 7 to have any body in them. They are all blank 
>white. 
>I have tried increasing the 
>intensity of the black ink from within the printer properties 
>without success at all. I even went to transfer setting and 
>adjusted the curve in the direction I thought would give me the 
>desired results, without any avail. I indicated to the printer 
>it was to print in grayscale mode and had assigned Dot Gain 30% 
>with Photoshop. I was using Quadtone printing very well before...

Three things stand out to me here: the S750 printer, previous
quadtone printing, and Dot Gain 30%.

1) The printer - perhaps there is an issue here where this model can't
do good BO printing.  I have an HP 6122 (for general office work)
which does does very poorly at BO (crummy dithering pattern).  In your
case it might be a problem with the image, so one way to test the
printer's capabilities is with Paul Roark's enhanced gray scale step
wedge, available in the Files section of this Forum.  Or just make a
21 step wedge in PS with the gradient and posterization tools.  Print
it with the back end profile set to "Same As Source".  If it prints
poorly, try different paper type settings and find the best one.  Also
try the printer gamma setting if there is one (Epson Driver has this
under Black Ink setting)  Try everything _except_ profiles and
transfer curves to get the best step wedge.

2) previous quadtone printing - Are you trying to print an image
that was previously worked up for quadtone printing?  If so, perhaps a
different treatment is needed for BO.  I'm just grasping at straws
here, not knowing anything more about the image.

3) "assigned Dot Gain 30%" - from the description this sounds like a
front end profile, and it sounds like you are using it in an attempt
to affect the printed output.  Did you read article #4?  One of its
main points was not to use the front end profile as a tool to change
the print, but only to get better WYSIWYG.  It CAN seem to affect the
print if the backend profile is set to something other than "Same As
Source", but that's because when the two profiles are different they
work against each other.  One pulls while the other pushes, and each
possible combination has a different effect.   So when you change the
front end profile, both the screen image AND the printed image change.
 So it's a less intuitive way to work.  DG-30 seems like an awfully
radical front end curve, especially remembering that these curves
change the contrast as well as the brightness.

So what to do?  Assuming that the printer is capable (prints a good
step wedge), the problem must be in the image itself.  I'd try, for
starters, setting front end to DG-20 (because it's in the middle of
the brightness range), back end to "Same As Source", and make a
print. 
Then adjust the front end profile, up or down, looking for a screen
image that most closely matches the print.  Now you have a profile
setting that gives good WYSIWYG.  Now look to see if you can see
detail on the screen in the zones from 7 on up that look washed out in
the print.  If you can't see much then the image needs adjusting.  If
the image looks good on screen...then I don't know what to say.  Maybe
the Canon deiver???

Good luck with it.  Please let us know what happens.

Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm