thanx for answering, gary!
yes, i heard about these opinions, too - as well as from the
other side (the painter's opinion): you can't walk around a
painting... in that case i think that 180 degrees are at least
half a circle, and i've seen works of the renaissance, in which
famous painters played with that fact and painted details you
only can detect if you look from very aside of it.
perhaps 'colouring' sculptures is a better word for what i mean.
that includes the possibility of variing the intensity of the
color (like much color in the trays and less on the vaults) to
avoid this flatness effect.
but there's still the main question left: WHICH SORT OF COLOR
is the most appropiate for stone-colouring?
ulli, the lucky dog

Two avenues i am exploring, is raised relief fresco, particularly tropical type leaves and flowers. Another is the technique of scagliola, do a websearch to see some examples. This is high quality fake marble, which can be built up or cast. There are many examples in U.S.A and Italy. You can control the veining and coloration, making it very suitable for architecture and sculpture.

As far as colouring real marble, it will seem unusual at first, but I would pick colours which do not occur in marble - such as iridescents, metallics, luminescent. Do you know about www.kremer-pigmente.de? I also have some German luminescents which are very exciting, they glow in the dark for hours, available in yellow, green (the high performance ones) and also deep blue and rich red. I am casting clear resin mosaics, which have been backed with the luminescents, the effect at night is beautiful and subtle.

The idea is comparable to taking a beautiful natural product, such as a beautiful woman, and adding accents, in much the way she might add makeup, to accentuate certain features, etc. It can be grossly overdone or barely noticeable- either way unforgettable.