Magenta Prints with an Epson P800, Photoshop 26.8.0. Mac OS 15.5

Hi Barnack7, oh boy - under those conditions like unscrambling an omelet. OK, here's the thing: there are three legs to the process of getting a print from a file: what happens in the editing Application (e.g. Lr or Ps), what happens in  MacOS (the CMS and PCS (color management system and profile connection space within it) and the printer driver. The interactions all happen under the hood and they could vary depending on software configurations in ways that are obscure to users like us, which complicates understanding the source of issues - perhaps even to Epson technical support staff except at the most senior level. I am concerned that they pointed you only to Adobe, when the source of the problem could perhaps also be in the OS - or in the Epson driver. I have also been plagued with colour management issues trying to print directly from Lr using Ventura with an Epson SC-P5370, and I was advised to print using Epson Print Layout (EPL) but through Lr - by exporting the file from Lr to EPL. EPL uses the Epson driver beneath its interface, but somehow this procedure seems to work around whatever problems were happening printing directly from Lr without EPL, because the result was fine - systematically so. Therefore let me suggest that you try printing through Lr+EPL and see what happens. if this produces a correct print, it may indicate the problem is with either Photoshop or the CMS, or how they are not cohering properly. BTW, if you are using a V4 printer profile, it may be useful to try using a V2 profile, if avaiulable to you, and see whether that solves it. Also try sending 8-bit rather than 16-bit data to the printer, a control you exercise in the Epson driver options and Photoshop or Lr. Both these changes have been known to solve problems. 

Mark, Thank you for the quick response. The computer itself is new (iMac -> M4 Mac Studio, the OS is new (MacOS Ventura 13.7.6 -> Sequoia 15.5), and Photoshop is different (24.7.5 -> 26.8.0), so everything has changed. The print of Epson's test image from Preview demonstrates there is no hardware issues with the printer. Epson says I should let Adobe know of this issue.

When encountering such problems one normally wants to know what may have changed in your set-up and/or workflow between the last good results you obtained versus ther first poor one, as this would help pinpoint the source of the problem. For example, had you up-graded the operating system, had you upgraded any other software? Was there any other evidence of sudden printer malfunction (persistent clogging)? Have you found (from searching) whether other users of the same printer and sofrtware combination have had a similar issue?