Digital BW, The Print

You have to think like the printer does. To make a tone, you put dots on
paper. To make a tone as dark as you can, the dots touch so that there
is no paper showing. 

To make a lighter tone you can go one of two ways. First, you can space
the dots apart, and the resulting tone is a combination of the color of
the ink, and the paper. If little paper shows, the tone is darker. If
mostly paper shows, the tone is lighter.

If you are using a single ink (black only printing, for example), to
make the lightest tones, you spread the dots very far apart. In very
light areas of the print, you can then see the dots, because the very
dark dots stand out in the sea of very light paper.

The second way, is to use dilutions of the black ink. This allows you to
bring the dots closer together to create the same tone. The lightest ink
in a quad set, for example, may be only 7% as dark as the black. That
is, for a tone that is 7%, the printer would make the dots touch, with
no paper showing (that's not really how it works - there are xovers and
most tones use more than one ink, but I'm keeping it simple for the sake
of argument). That's as dark as that ink can be. As the tones decrease
to 1% or less, the dots are still very close together - thus "dotless"
printing, yes?

Now we go to a variable tone set - one that has four dilutions of black
(a quadtone set), plus a warm toner and a cool toner. 

The two toners are single dilution inks. To tone the lightest areas of
the print, the printer uses the dark toner dots spread very wide apart.
Sometimes you can see the dots of toner, just like you can see the dots
of black when you do black only printing.

And that's why, for "dotless" printing, you need a fixed tone quad ink
set.


On Wed, 2004-04-21 at 13:00, mike_nunan wrote:

> Hi all,
> 
> This is my first post here so treat me gently ;o)
> 
> I've been researching the world of dedicated B&W printing for a 
> little while now, getting ready to take the plunge with (almost 
> definitely) a second 2100 to sit alongside my existing unit, which 
> I'll keep for colour use. I've sifted through a lot of the discussion 
> that has gone on here, and I think I've got a pretty good handle on 
> most of the issues. I've also swapped a bit of direct email with Paul 
> Roark which has been very informative in getting to grips with the 
> finer points of UT7 (thanks Paul!)
> 
> I've got one question to ask now, one that springs to mind after 
> reading Steve M's recent thread about using quadtone inks in a 7000. 
> He implies that if you want "dotless" printing, then you want a true 
> quadtone inkset. It seems logical enough that having a fine gradation 
> of different ink shades would help hide the dots, but what I don't 
> understand is why it would be much different for say UT7 using Paul's 
> workflow. If you don't use the cold and sepia toners, then you still 
> have pure black plus two shades of grey to work with -- essentially 
> a "tritone" pure carbon inkset. Why should that be noticeably more 
> dotty than a quadtone? Or is it more to do with the effect of the 
> RIP? But in that case, why doesn't QTR give similar results?
> 
> Yours confused,
> 
> Mike Nunan








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