In my senior year of high school, I took an elective semester course in archaeology. On day one of class, the instructor wanted everyone to understand that real archaeology has no resemblance to the adventures of Henry Jones, Jr. (aka Indiana). Those of us in the classroom with bullwhips and fedoras in our backpacks were disappointed to learn that real archaeology was about slowly digging around shards of pottery with very small brushes and not about melting bad guys with ancient artifacts.
As the crew of MythBusters has demonstrated for over a decade, a lot of what is depicted in film and television is about spectacle over reality. You can sit back and enjoy the cinematic ride, but it can be hard to turn off that part of your brain that really understands how certain things work. My poor wife must cringe whenever something appears on screen that might put me into a scanner-nerd fugue state where I am compelled to explain, yet again, how “it doesn’t work that way.”
Take for instance the popular spy/action movie trope of the heroes enhancing the footage from a security camera to get a crystal clear image of the bad guy. If you’ve seen real security footage on the evening news, even the enlarged version is usually badly pixelated and motion blurred, but it seems as if every security camera in a movie is at least HD quality and can be zoomed in to see the miniature map to the bad guy’s lair hidden in the design of his cuff links. (“Hah, your fashion sense has done you in again, Baron Nefarious!”)
In working with scanners all these years, the myth of “resolution = quality” is one I’ve encountered a lot. There is a correlation with printers and the dots per inch on paper to image quality, but in scanners, the dots per inch of resolution has a lot more to do with image enlargement than quality. In an imaging system, the quality of the image is ultimately decided by the optical sensors. A scanner with a good sensor and high resolution can give you a great enlargement from small media, like a 35mm slide, but only if the source is also great.
Once at a trade show, a gentleman wanted me to scan his 35mm slide at highest resolution and was irritated that the final image wasn’t as tack sharp as the other slides I was scanning. He was not aware that his slide was simply out of focus and the scanner was enlarging exactly what it was scanning – a fuzzy, out of focus image.
As the great humorist Tom Lehrer quipped on his album That Was the Year That Was, “Life is like a sewer, what you get out of it depends on what you put into it.”
The same can be said about scanning – no amount of resolution can fix a bad image.
Thoughts? Questions? Tom Lehrer Quotes? Drop me a line!