Digital BW, The Print

Hello John,

>I'm a newbie to the group and to digital printing

Welcome to the forum.


>What is BO printing ?  I know it means "black only", but what
>exactly does that mean?  At first I thought it mean checking 
>the "Black" box in the Epson printer driver, ignoring the 
>"Suitable only for text" warning, and manually setting the 
>DPI to 1440 or 2880.  

Yes, that is exactly right.


>It's clear from reading here "BO" also includes use of the after-
>market inksets from places like MIS, which apparently use a small
>number of inks of various shades of black. 

No, not necessarily.  You can use any ink you want.  However, most who
are interested in longevity do not use the original Epson inks if
using models previous to the 2200 series.  The 2200 printers come with
the Ultrachrome inks which are longer lasting.  The primary longevity
issue with inks is the amount of dye vs pigment they contain.


>The first method ("BO1") I have used on my Epson 2200, and the prints
>look pretty nice, but I can imagine the fill is a little "rougher"
>in the highlight areas; these must be the "dots".  (Yes, I am very
>far-sighted).  I still prefer the prints to those made using all 7
>inks; the latter look fine under artificial light, but kinda a
>gun-metal blue under daylight; I assume this is "metamerism".

Correct on all counts.  The visibility of the dots is the big issue
with BO prints - some find them acceptable and others don't.  The
metamerism with the full ink prints is an entirely different and
important issue.


>The simple BO1 method on the 2200 only uses one ink cartridge, so
it's
>easy to see why it has "dots".  What I don't understand is why
>one of the after-market inksets (like MIS) should be any more prone
>to dots than a print that uses all 7 colors on the 2200, since they
>have 4 or 6 cartridges with various shades of grey (as I understand).

They aren't more prone to dots.  There is no difference in dottiness
from one ink set to another.  The size and pattern of the dots is
determined by the driver software and does not vary with different
inks.  The real difference among the different non-BO methods, whether
they have dots or continuous tone, comes from the software and
workflow techniques.  However, inks do differ and some software may be
written with certain inks in mind, so there may be an association
between a particular ink/software combination.


>Finally, given that I want to stick with the 2200 (since I want to
>do some color too, and I don't want to buy another printer right
>now), what course is best for me?  

One of the advantages of BO printing is being able to do color and BW
with one printer.  The big question is whether the BO prints are
acceptable to you.  If they are, then you're in good shape.  If not,
then you have some decisions to make.  There are some articles on my
web site (see link below) which discuss these and related things,
including some Photoshop tips.  They might help clarify some of your
questions.


>How much worse are the dots using the "BO1" mode than when using 
>the more broad definition of BO printing?  

They aren't worse, and there is no "broad definition".  It's either BO
or it isn't.  However, there is a RIP called PowerRIP (used by Daniel
Staver) which does BO using both the blacks on the 2200, with very
pleasing results.  I refer to this as BO2 (BO with 2 inks).  The
difference is that some of the dots are made with light gray ink,
which makes them less noticable.  Normally all the dots are black ink.


>Should I try to do the Grey balancer thing ?   

I can't answer that.  Someone else...


> Thanks for clearing of confusion and advice, John

You're welcome.  I hope it helps.

Regards,
Clayton


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