The gee-whiz aspects of “Side by Side” are integral to its argument. The film is not quite an exercise in pro-digital propaganda. Skeptics as well as enthusiasts are heard from, and the virtues of old-fashioned celluloid are duly praised. But as is so often the case with digital technology of all kinds — the tablet, the mp3, the Internet itself — the discourse tilts toward triumphalism.
The tried and true always has trouble competing with the shiny and new, which in this case offers convenience and portability as well as up-to-the-minute coolness. There is something inherently appealing about belonging to the party of progress, and quite a few of the cinema artists Mr. Reeves interviews make their preferences for pixels and CGI sound like matters of principle. They see themselves as a vanguard, pressing forward with innovations that are aesthetic as well as technological, if such a distinction even makes sense anymore.