Originally Posted by
Manfred M
It depends, Jack. If you have the original (raw) file and the shot was made with a camera with a decent size sensor, the answer is probably yes. If all you have is a low resolution JPEG, it might not work as well. I've made a print from my 36MP raw capture D810 into a high quality 36" x 48" print that is very sharp. Just remember the image you are working from has to be high quality (sharp = well focused and no softness from camera movement).
Just resizing the image in Photoshop might be good enough. I regularly make 17" x 22" prints and just use the Photoshop reizing algorithm. Go to the Image menu an select "Image Size" and set the Resolution to 300 pixels / inch (360 pixels /inch if you know an Epson printer will be used), set the size the Units to inches instead of pixels and let the internal Photoshop algorithms do the resizing. When finished double click on the Magnifying Glass tool to go to 100% size and see if the image looks sharp enough.
If that does not work, then the current versions of both Photoshop's Adobe Camera Raw and Lightroom have an algorithm called "Super Resolution" which works remarkably well and will upscale the image to 4x the pixels. Third party software from Topaz called GigaPixel has even more capabilities than Super Resolution, but tends to create more noticeable artifacts.
Right click on the icon of the image in ACR or LR, click on the "Enhance" selection in the list that pops up. Then select "Super Resolution" and let the software do its magic.