I really think you are unlikely to see much difference between these two printers for printing on matte media. The gloss optimiser cartridge on the R1800 only comes into play when printing onto glossy/semi-glossy resin-coated media. The R1800 has red and blue inks in its ink set while the R2400 has the more usual CcMmY configuration , but with three blacks (K, LK and LLK). In theory, this should make the R2400 a slighlty better photographic printer, although in practice, the differences are likely to be very small. Given that the R1800 is significantly cheaper, I would have thought that that is the one you should be looking at first. Both use ultrachrome inks.