Just started with this problem today. Go through the normal procedure of preparing an image to print on the Epson on 13x19 paper. Can view the image as it is supposed to print but what comes out is a print in 8 1/2x11 dimensions and cropped to the center of the image. Contacted Epson support and wen through the entire procedure several times with tech support with same results. We tried to print off Preview and the image printed as it is supposed to. Epson support said the problem was not with the printer but with Photoshop blocking the command. What gives?
Photoshop sends the full image to the printer, at the size you specified.
But the page size selected is up to the printer driver, and printing it correctly is up to the OS and printer driver.
And there is no command for Photoshop to "block" -- it sounds like Epson didn't understand the problem.