I dont have a R1800 But I have R1900 printer. Disable printer ICM. Let PS manage Color. The New R1900 Out of the box with epson ink and epson paper and Epson paper ICC. The print came out pretty close to my screen (i would say 95% to what i see). Black and red are a bit darker.
I than calibrated the monitor and the printer to the paper I will be using (epson glossy). Calibrator software creat a custom paper ICC profile. I than Select this new profile when printing. The Image came out 100% to my screen.
My old RX580 with ebay CISS, Cailbrated. Print come out 95% match
My epson 2200 with Ebay CISS, calibrated. Print come out 99% match.
You CAN NOT USE third Party ink WITHOU recalibrating or use Epson ICC. Samething if you change papers. You will need to calibrate a new ICC everytime you change Paper(every batch of same paper will have minor shift) or INK. Ink color will shift over time too.
It is not hard. I have colormunki.
1) It calibrate the monitor(taking ambient light into account. Most newer Calibrator does this).
2) Program calibrate the printer(Ink to paper). Prints out a color chart. using calibrator to scan the color. Program will create a ICC profile for the paper.
I always had problems matching the print out to the monitor till I brought the colormunki. Having a calibrator does save alot of time, ink, paper and headach.