Digital BW, The Print

Olivier wrote:
>> Yes, depends where it falls. Could be less dots, distribution 
>> of the dots, smaller droplet size, a lighter ink in the 
>> inkset. In that order I think but there are many different 
>> media around that will not all cope with only dot number 
>> changes (and that's limited too if you want to keep some 
>> smoothness). In RIPs you can change the point where darker 
>> inks are replaced by lighter inks and Epson must have that 
>> choice too when making the paper settings for the driver.
>>

> In fact, it's in the 95-100% range I was 
> wondering relating it to Dmax. 
> 
> Again at a given dot size (forgetting VDS here), ink set... I'm 
> assuming dot gain will be the ultimate factor in ink limtiation, 
> meaning on one hand the paper on the other hand the dpi resolution. 

I have made a step wedge for QTR with some checks on bleeding.
Usually on good papers the Dmax stops increasing before the
bleeding gets ugly. Looks like the chemists have an idea how
to keep the print characteristics of the ink under control.
> 
> Say paper is given again, I'm left with dpi and a direct relation to 
> larger dpi-smaller fixed dots (at 2880). I've seen you repeatedly 
> mentionning smaller dots lead to higher relative dot gain (unless 
> wrong) : so where do we stand in terms of reaching higher Dmax. We're 
> better off with small drop or larger ones ? 

You can bet that Epson engineers fix the relation between the
different dotsizes on an average dotgain. So not a 1:2:4
relation on dot area but a 1:2:4 relation on actual density
measured in tests on several papers. You run into a different
problem with smaller dots, the placing of the smaller dots
gets far more irregular than they are with larger dots. The
differences between smaller droplet contents is higher than
between larger droplets contents. The pro printers almost
always had larger droplets than the desktop models and Epson
mentioned that consistency of droplet size was more important.
So you either choose for a more precise dot placement but
slightly rougher screen or you go for a finer dot with more
fluctuation in the density and in detail. The Dmax will not be
better at 100% when there's no white left. The control of the
95-100% range isn't better with smaller dots either.

There's a good piece of PR on the new Canon FINE heads here:

http://consumer.usa.canon.com/pixma/press/FINE_TG_0909.pdf

Propaganda but I think they mention some important issues.

> View like this I'd go for higher dpi and smaller dots. Basically, I'm 
> still stuck with what best dpi reso to use despite hundreds of posts 
> on the issue and Roy's mentionning 1440 is very fine vs 2880 makes me 
> wonder, because the 95-100% will probably use larger dots and put 
> together with your saying smaller increase dot gain and density make 
> me thing Dmax can/should be increased with smaller dots.


At the highest resolution the number of droplet sizes get
less. The evolution we have seen  with increased resolution is
a smaller minimum droplet size, more droplet sizes, more grey
inks. For a good reason as just making droplets smaller isn't
working.

> I'm sure I've got something wrong here...

I'm sure it is more complicated than we both think it is.

Ernst
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           Ernst Dinkla


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