The "just taken yesterday" appearance of those slides is due primarily to two causes. First, my Dad's meticulous attention to detail, cataloging, and archiving. His slide collection is housed in a number of hand-made boxes, designed to keep the slides immobile, in order, and away from light and other contamination.
The other cause is this:
... no, not the bear, but the gizmo the Alcatraz bear is sitting on: our slide scanner. The scanner and its associated software can do miraculous things for old slides. Through a combination of hardware, software, and a database of emulsions' aging characteristics, Dad's thousands of old slides are coming back to life. Here are two examples from the last post, the ones I called "Beach frolics" and "Mom and me in a roadside diner." Both photos were taken in April, 1961.
"Beach frolics" after the scanner removed most of the physical flaws in the slide: dust, scratches, etc.Physical flaw removal seems to be accomplished by way of an infrared sensor that detects items above or below the surface of the emulsion (dust and scratches, respectively, for example) and proprietary software that "fills in" those areas according to the characteristics of the surrounding healthy emulsion.
Other examples of slide restoration in this years-long project can be seen here, and there are many, many more options, bells, and whistles in the hardware/software than I will ever learn how to use. But that's okay; the aim for me is to preserve Dad's pictures the way he wanted them to look, and I think we're doing that pretty well.
Side note: the computing resources this project takes up has given me an abiding appreciation for the staggering magnitude of a little 35mm slide's analog data storage. I store each slide's scan in a "raw" format, from which any number of graphics programs can operate on the image. To preserve as much information as possible, I have all of the quality preservation options maxed out, which yields a typical file size for a single slide of about 120 megabytes, and, even at that, I'd bet that I'm not within two orders of magnitude of capturing all of the information on each slide.
Look back at the second slide, the one showing the scanner. Next to the scanner, behind the dancing bears, is a DVD burner. Beside that, with the blue light, is a Seagate 500 gig external hard drive. Those are just a fraction of the data storage and backup that this project uses, but I worry about them. I wonder if the media they produce will even be readable as long from now as now is from when the slides were taken. Oh, well, maybe that will give Grace a hobby in 2056 or so.