In article , dga2@po.CWRU.eduÒ says...
>I've been hearing that different brands of lenses yield noticeably
>different color casts. The guy who told me this (a camera equipment
>salesman) also said that anyone who wants to have his/her work accepted >by the art director for any agency or publication had better not mix >and match lens brands because of this color shift. `(...)

I own a lot of lenses (mostly Nikkors), including some of the few off-brand lenses that satisfy this finicky lens user. I find that
the color balance is different with other brands, but it can often
be made to approximate the Nikon color balance by trying to match
a grey subject shot on slide film with different brand lenses
using various brands of (mostly) skylight filters (which also vary
in color). For instance, the 90mm Series I macro and the Tamron
28-135mm SP required moderately colored skylights to match Nikkors
with UV filters on, but a Schneider 150mm Componon S required a very strong skylight filter, and a Sigma 8mm (fortunately) required no
filter. Gel cc filters can be cut to fit behind a UV filter for
other color shifts. It is better to have color-matched lenses if you
are shooting picture stories, but otherwise....

(much deleted, answered above)
>Finally, do most publishers still require slides or are color
>prints/negatives more accepted these days than in the past? It seems >that fast color print film (ISO >= 200) gives better results than slide >film in the same speed range and use of such print film would allow the >use of slower, lighter and less expensive lenses.

The above seems obvious to us photographers, but when did (will) a
buyer ever listen to a photographer, let alone ever know much about
the process of photography?
Hope this helps.