In a word "technology".

The term C-type print is often misunderstood but is generally understood to refer to a film original (i.e. transparency or negative) that has been printed optically through an enlarger, using a lens, onto traditional wet chemistry colour paper. Strictly speaking the term C-type appears to be a reference to colour negative chemistry processes used by Kodak and originally came into use during the 1950s.

This is distinct from a B/W print produced optically onto wet chemistry paper, usually known as a B/W silver halide print.

Colour exhibition prints produced digitally through a computer connected to a Lambda or Lightjet machine are often seen labelled as C-type prints. This is not strictly true as these prints have been produced by exposing photographic paper using digital laser or LED equipment, and then wet processed.

If you do visit an exhibition or gallery and see labels indicating C-type prints then it might be worth asking for an explanation of the actual process and technology used. Museum curators and commercial gallery owners need to be aware of this.

Code Ice prints are produced using archival rated high dynamic range pigment inksets on a wide format fine art inkjet printer using media certified by the Fine Art Guild, UK.

In terms of image quality there is probably little to choose between print methods but the technologies involved are very different and each print type will have it's own characteristics. It therefore becomes purely an aesthetic matter.

Which will last longer - a C-type or a Code Ice inkjet print?

The only certainty is that no-one can actually guarantee anything, even C-types! Stored correctly then both are likely to last a long time.

However conventional RC colour photographic papers (commonly used for C-types) are resin or plastic based materials and these materials are not known for their archival longevity. A paper often quoted is Fuji's Crystal Archive paper, however ratings that we have seen only refer to about 40 years lightfastness.

Compare this with true fine art inkjet media where acid free, cotton based rags are used in conjunction with pigment inks. Independant testing by organisations such as www.wilhelm-research.com indicate lightfastness ratings for inkjet prints up to 200 years on the correct media and their website is a good place to learn more about the subject.