Why are Epson UltraChrome K3 prints so scratch-resistant? And what about fine art papers?

• Epson UltraChrome K3 Ink Technology uses a different method of “binding” the particle of pigment and the glossy resin encapsulation called “CrosslinkingChemistry”. This chemical process makes the prints significantly harder than the previous Epson UltraChrome Ink technology. As a result, the scratch resistance is amazing on normal RC or Photographic-grade media types.
  
  Fine art papers also benefit, but there is another problem. Although the ink is harder to scratch off, the surface of the print can get “scuffed” and the print will still have a “scratch” (Similar to moving your hand across a suede jacket). The ink did not come off, but you still ruined the print. So be careful when handling prints on this media.