The display is 3840x2400 monochrome pixels, to drive via HDMI, 3 consecutive horizontal pixels are wrapped into one RGB pixel. Therefore, the display is driven as if it were 1280x2400. PC and Raspberry cannot do this conversion directly, so the view is compressed in vertical direction. In order to get full monochrome resolution for photomasks one has to prepare a monochrome image of the mask with the size of 3840x2400 and afterwards one has to map each 3 consecutive pixels to a pseudo-RGB image with the size of 1280x2400. This might be done using python and numpy array rearrangements. In this way you can display at 4k monochrome resolution images while driving the display at less than 4k but RGB. 3D printer manufacturers do this conversion for png files to be displayed in their firmware, which is freely available around the internet (GPL). So, if you buy this as replacement part, you will never encounter this issue. But if you want to build your own hardware one might stumble.
The display is 3840x2400 monochrome pixels, to drive via HDMI, 3 consecutive horizontal pixels are wrapped into one RGB pixel. Therefore, the display is driven as if it were 1280x2400. PC and Raspberry cannot do this conversion directly, so the view is compressed in vertical direction. In order to get full monochrome resolution for photomasks one has to prepare a monochrome image of the mask with the size of 3840x2400 and afterwards one has to map each 3 consecutive pixels to a pseudo-RGB image with the size of 1280x2400. This might be done using python and numpy array rearrangements. In this way you can display at 4k monochrome resolution images while driving the display at less than 4k but RGB. 3D printer manufacturers do this conversion for png files to be displayed in their firmware, which is freely available around the internet (GPL). So, if you buy this as replacement part, you will never encounter this issue. But if you want to build your own hardware one might stumble.