I will pretty much jet let this photo of a print I got out of my PRO-4000 do the talking. What on earth is wrong with this printer? I would say maybe it's a print head problem, but the nozzle check pattern is ok, and if it's a print head (recently replaced BTW) why only a problem on half the page??
Well I’d check your gamut warnings and your rendering intents. Also if you post the image as you are sending it to the printer. But one idiot proof way of working around all color issues at the expense of finesse is to convert to jpeg and sRGB and let the printer do the color management.
I really didn't want this post to be something to dissuade anyone from doing their own printing if they can swing the initial cost. Because, yes I am having some issues right now, but I owned a PRO-1000 before this since around 2017 and it was great, and I have had this since I think 2019 and it has mostly been very good.
Not only that, but seriously the ink and paper costs doing it yourself are somewhere around 10-20% of the cost a good photo lab would charge. So even if you encounter issues, honestly you can screw up multiple prints and still be ahead of the cost of doing it at a lab. I also was just never super happy with the results I was getting from a lab. Sometimes it was almost good, but I really like having the control over everything myself, and being able to make my own call about when I want to do a re-print, compared to getting something from a lab and accepting it even if it's not quite what I want because I don't want to ask for a re-print for something that is so close to being good, but not quite.