Depending on your area (US or EU) you can buy refillable cartridges (no chip transfer needed: the cartridges have their own chip unlike the previous Pro 3800/3880 that works with a chip sensor that reads the original chip) or refill the original cartridges (modification needed of the one-way valve). In the EU the refillable cartridges will auto reset: when empty, remove cartridge from printer, refill accordingly and re-insert and the chip level will show full again (the printer will bla bla bla complaining about aftermarket cartridges, just overule and ink level is restored back to 100%). The US version can only be used onced, but you can buy the chipless firmware to flash the printer in order to get ink level at 100% for eternity (do NOT update firmware). The chipless firmware route is also recommended for EU users who wants to refill the original Epson cartridges.
I have very good results with Inktec Powerchrome K3 Vivid ink: the ink is precisely formulated to be compatible to original Epson K3 Vivid ink (see my posts last year for the Epson SC-P900 using Inktec Powerchrome K3 inks): no need of extra profiles) and is resin coated (scratch resistant and high gloss....even better than original Epson K3 vivid ink). The only negative thing is the PK (photo black) that is not only overly glossy/shiny (giving a strange metallic sheen on the prints) but also has a less deep black level compared to original Epson PK ink. For this I use large 350-700 ml old expired Epson PK inks to refill my PK cartridge. Inktec Powerchrome K3 ink is produced by a korean company and is very good in color rendition and has excellent properties (almost never clogs), high gloss and high scratch resistant and is pigment ink too like Epson.
If not printing on glossy paper and you can deal with a less glossy ink I suggest to use the cheaper but still very good ink from Ocbestjet (aliexpress.com), but this ink needs profiling. The gamut is on pair with Epson/Inktec Powerchrome but the ABW-mode is off, giving a sepia glow over it. With profiling the results are very good on satin/pearl and matte papers (less on glossy papers: for this I recommend original Epson or Inktec Powerchrome K3).
