Art - I leave my wife's ip5000 printer on the plain paper default setting
except for the rare occasion when she wants to print a photo. She prints
mainly web pages that do have some color included. With mixed text and
color pages I believe that the printer still uses the BCI-3ebk cart when on
plain paper setting. This "best guess" is based on the fact that I rarely
refill the black dye based cart, but the pigment based cart needs to be
refilled more frequently. No problem with mixed text and color on the page.
It is only used when the paper selection is plain paper and duplexing is not
used. Obviously, the printer doesn't know if what it is printing is text or
graphics, so it relies on the paper setting for which black ink cart it
uses. You are correct that the BCI 3ebk cart is pigmented ink. I've seen
reports, however, that some BCI-3ebk refill inks and some prefilled
aftermarket carts are dye based and not pigment based inks. Purchasers
should verify that they are receiving the proper inks when buying these
products. The Canon aftermarket ink vendors that are mentioned most often
here as reliable can be reached by phone to clarify this issue.
I haven't experimented with the gray scale setting, but, in my estimation,
there is no need for it when printing primarily text, and it may not work
properly anyway as you suggest. (that is, unless you really want a black
printed page only.) My wife's previous printer had only the dye based inks
and I was not refilling carts then. To avoid using the color inks we turned
on the gray scale setting. No need to do that if one is printing a
predominantly black text or graphic page. If there is a little color on the
page it will probably use a very minor amount of color ink compared to the
ink that gets dumped into the bottom of the printer with cleaning cycles!
In addition, any ink you use has to be replenished, and the cost of all the
inks are comparable. Bottom line - if gray scale is selected to save money,
you save very little by using black ink instead of color ink. If money is
really the issue you would do better by refilling with good aftermarket
inks.