I've been printing some images directly in Photoshop to my HP Photosmart Premium on some glossy photo paper. I've also been printing some of those same images, but they were placed in hi-quality pdfs. The pdfs opened in Acrobat are printing exact actual size, but the images printed out of Photoshop are printing slightly larger (almost 103%) beyond actual size. And yes, scaling is set to 100%—all images are much less than the letter size paper setting, etc. For example, the images average 9.46" wide x 4.717" high and are printing about 9.875" wide x 4.82" high on letter-sized paper. It clearly is not a print-to-fit issue. Is there some setting in Photoshop or its interaction with this HP printer anyone knows about that is causing this problem, or something I should know? My only solution printing within Photoshop would be t scale the print down to 97.4% and then all is fine. I'd like to know why this scaling is happening despite all settings actual size or 100%. Thanks.
This happens when you mess up the DPI settings and print at non-native DPI. Apparently this causes some quantization issues in the printer driver. You would need to figure out which eefective LPI/ DPI your printer uses and then resample your images in PS to that same value or the closest even DPI.