this is what Nations Photo Lab told me about their printing:
"For our Photo Prints, we do not use inkjet printers. Instead, we produce Chromogenic Prints, also known as Silver Halide Prints. Our Photo Prints are made using a digital image and developed using a chemical process. Silver Halide Photographic Prints are composed of three layers of gelatin, each containing an emulsion of silver halide (used as a light-sensitive material). The photo paper is exposed to light and in turn, the image is infused into the paper through a chemical process. The resulting prints have more depth, more vibrant colors, more details in highlights and shadows, are sharper, and are less susceptible to fading/damage as seen with Inkjet Photographic Prints. Inkjet Photographic Prints involve a process of applying ink to just the surface of the paper!"