What's the most likely cause of grain in this photo?

Question

I took this photo recently w/ an old Pentax K1000, using 400 ISO film, and an f/1.7 aperture. Is this graininess just inherent to shooting w/ this sort of film / lighting? Or, is it partially/largely caused by the scanner that scanned my photo?

In other words, is this just how it's going to be no matter who scans my photo? Or, should I be looking for a different place to get my processing done?

Answer

ISO 400 film is almost always going to have grain that's at least somewhat visible. I can't really tell if you underexposed the picture or not, but underexposure will generally make the grain much more apparent.

Different scanners show grain to (slightly) differing degrees. Basically, the smaller the light source, the sharper a rendition of the finest details it'll give -- and the more apparent the finest details like grain will be. A larger light source "softens" the scan a bit, which tends to make grain slightly less apparent. Unfortunately, if you're getting the scans done commercially, you may not even be able to find out what sort of scanner they're using, not to mention getting them to select a different one that's more suitable for a particular picture.

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