That much is pretty well established in some of my previous posts. And admittedly, the best place to find these old original slides is from the auction site ebay.
However, a search on this site on just the term "vintage slide" yields over 5500 results in the Photographic images category at the time of this writing. Certainly I fan through the mass of pages and just pick shots at random, right? Not so much.
Sometimes, I'll take a chance and buy a collection of slides or a bulk lot, but I've found that the best way to get specifically the images you want is to bid on listings for single slides, or small lots of under half a dozen. When searching, I am likely to use somewhat more specific terms such as "1951 Kodachrome" or "Los Angeles Slide," but even then, there are often a number of options, some of which are better than others.
I've found it helpful to set up some establishing criteria. Off the bat, I'll tend to skip auctions offering commercial "souvenir" slides that were once available at touristy locations. While certainly well composed photos, these images used a replication process that has left them very prone to fading. Similarly, I'll also tend to bypass auctions of "Magic Lantern" slides. These images in their larger format, while interesting, are also more a commercial colorized version of a black and white image and not true color. And while I'll entertain duplicate slides, I admit there's a certain appeal to having the actual piece of film that was on location to "see" the scene it has replicated
Once an image has passed the "first screening" of the criteria above, I then get to prioritize items on my ebay watchlist using the following questions. Obviously, the more questions the image can answer favorably from the following list, the better the chances are that I should want to to add it to my collection. Here goes:
1 - Is the image impossible to replicate today?
This is actually the single most important criteria, as I'd admittedly be more likely to pull the trigger on a somewhat problematic photo of a late 1960's city scene that has since radically changed over a pristine image from 1938 of a simple waterfall that looks exactly like what visitors to the area see today. The element of change is a big part of the appeal of a nostalgic image.
One simply can't get a view like this when looking west towards the Lincoln Memorial from the Washington Monument today, but the view of June 1952 was cluttered with these temporary government office buildings in space that today is park land.
2 - Does the Context interest me?
This one is really pretty critical as well. I find that I'm most interested in outdoor "street scene" photos of the U.S. that quickly convey the era in which they were taken. I definitely like to have some people donning period styles present in the image, but an absence of them certainly won't stop me from bidding. Fixtures such as old cars, trolleys, buildings, commercial fronts, traffic lights, and other period revealing elements definitely add on "brownie points" for an image's appeal to me.
Long retired "L" cars and lots of vintage dress led me to pull the trigger on this 1978 view taken in a subway station in Chicago.
3 - Is it Old?
As a child of the 1970's steeped in nostalgia for the era before I was born, I'm not too likely to bid on much of anything newer than 1970. I'm definitely partial to the 1950's, and have a particular fascination for period revealing images of the 1940's. Given that Kodachrome, the first widely available color slide film, did not even come onto the market until 1935, and was really only stable after 1938, there are naturally limits to how far I can go back, but I will admit that I do actively seek out what I can find of the rather rare photos taken before 1946.
Practical color photography was still very much in its infancy when this August 1940 was snapped on one family's rest stop in Greenfield, Massachusetts. US involvement in World War II was still over a year in the future.
4 - Does the color in the image look like it could have been taken yesterday?
This is where Kodachrome images tend to have a distinct advantage over the Anscochrome and Ektachrome images of the same period, as when stored in a dark environment, the dyes are far more stable than the other films. That said, even Kodachrome is prone to fading, so I try to keep an eye out for examples that have been well preserved with vibrant colors. In addition, dust on slides can be a major factor in image degradation, and although ICE technology and Photoshop can help remedy this to some degree, it's still better to start with as intact an image as possible to avoid a lengthy restoration.
The deep blue in the Florida sky and the rich aqua in the water appear likely appear just as vibrant as they did in 1949 when this image was taken.
5 - Is it a "quality" image technically?
A sharp, focused, and properly exposed image is ideal. That said, I certainly realize that the quality and capability of equipment has come a long way from what it was for the typical casual photographer of the 40's and 50's, and shooting photos on this kind equipment with ISO 12 speed film was definitely a challenge. As a result, I do realize that some technical flaws may be present in the photos I bid upon.
The photographer of this intriguing 1948 view of a bridge in Minneapolis, Minnesota made excellent use of focus, exposure, and composition when creating this image.
6 - Can I pinpoint the location?
Certainly not a showstopper if I can't, but it is nice to be able to know exactly where a photo was taken. And while a photo taken from an obviously apparent location is certainly nice, I'll also admit a certain fondness for being able to specifically pinpoint an image's location using small clues within the image itself. Sometimes I am successful, and other times not as much. And sometimes it takes the help of a reader to sleuth out the location. In addition to locations that can be determined, as a native Baltimorean, I'm going to have an obvious bias for photos taken in or near my hometown.
Not everything is as easily descriptive or recongnizable as this June 1952 image of the George Washington Masonic Memorial in Arlington, Virginia, but that can often be part of the fun.
7 - Can I afford it?
In a way, this is the most important criteria and the least important criteria all in one. I pretty much set an general limit of spending no more than $10 for a single slide. While many of the other questions are rather qualitative, this one "rule" is more of a quick Yes/No question. However, there is always an exception to every rule, so you can best believe that if I found a perfectly exposed, perfectly composed, impeccably preserved image of a 1939 street scene in Baltimore bursting with vintage nostalgic elements, I'd be locked into a bidding war to the death!
I've gotten some single images for under $2, while others, when bought in a batch, such as this 1950 image of a wintry Niagara Falls, were had for about 40¢!