Digital BW, The Print

Hogarth,

That is just what the Epson drivers do; they use all three drop sizes 
depending on the amount of ink to be laid down and the color mixing 
required.

For example, here is an extract from a decoded Epson R800 print file, 
showing the numbers of the drops of different sizes (d1-d3) of the four 
different inks ( r=B (blue), r=p (photoK), r=C (Cyan), r=Y (yellow)) used to 
print this grey band (rgb=25/25/25):-

Esc($ 4 AbsHorz = 10115
Esc i Data r=B c=1 b=2 hz=182 vt=180 d0=130887 d1=153 d2=0 d3=0
<cr>
Esc($ 4 AbsHorz = 10115
Esc i Data r=p c=1 b=2 hz=182 vt=180 d0=129345 d1=550 d2=921 d3=224
<cr>
Esc($ 4 AbsHorz = 10115
Esc i Data r=C c=1 b=2 hz=182 vt=180 d0=130512 d1=495 d2=33 d3=0
<cr>
Esc($ 4 AbsHorz = 10115
Esc i Data r=Y c=1 b=2 hz=182 vt=180 d0=130929 d1=111 d2=0 d3=0

Note that the PhotoK is using all three sizes of drops, whereas the yellow 
and blue are only using the smallest and the cyan is using the smallest and 
medium sizes.


At the other end of the scale, rgb=225/225/225, the grey band is printed 
using only the smallest drops of the three inks Magenta, Cyan, and Yellow, 
while the first ink line (wrongly labelled r=C) is actually the GLOP which 
is laid down in the white and near-white areas and uses all three drop 
sizes:

Esc i Data r=C c=1 b=2 hz=182 vt=180 d0=123701 d1=2917 d2=4281 d3=141
<cr>
Esc($ 4 AbsHorz = 4162
Esc i Data r=M c=1 b=2 hz=182 vt=180 d0=129975 d1=1065 d2=0 d3=0
<cr>
Esc($ 4 AbsHorz = 4162
Esc i Data r=C c=1 b=2 hz=182 vt=180 d0=130254 d1=786 d2=0 d3=0
<cr>
Esc($ 4 AbsHorz = 4162
Esc i Data r=Y c=1 b=2 hz=182 vt=180 d0=130797 d1=243 d2=0 d3=0

Isn't that what you wanted, or did you want completely variable drops sizes?

Bob Frost.

----- Original Message ----- 
From: <hogarth@...>

What I was envisioning (be careful there!) was a driver smart enough to
use all the dot sizes all the time, and smart enough to determine when a
given dot size was appropriate. The drivers (Epson, StudioPrint, QTR,
etc.) seem to be smart enough to run dither patterns and decide how to
place dots, and which dots to place, to make good smooth tonal
transitions. I just thought they could do this with dot sizes too,
because clearly variable dot size has the potential to improve the
smoothness of tonal transitions, and improve sharpness too. Yet variable
dot size doesn't appear to be used that way. My bad.