Some of my favorite street photos are the timeless moments. The moments caught, which could have been taken at any period, with only small details changing. Particularly those shots, where you think it was taken yesterday, but was actually shot decades ago, or those seemingly being from some time ago, but were just taken, are the best in my opinion.
But what makes a photo timeless? The answer is obvious, if you see a photo which makes you doubt when it was shot, then it's basically timeless. However, I believe there needs to be more to it. The surroundings need to be timeless as well, the theme of the shot as well. And while not necessary, I believe a black and white photo is easier being seen as timeless, as one in color, simply because color themes are dictated by fashion (as is clothes, so), and therefore can reveal more about the time the photo was done in, than if it had only been black and white.
When it comes to subjects, then there are some obvious ones. The romantic scene with two lovers somehow expressing their love for each other. The seller and buyer at a market stand. Friends having a good time. Or simply a photo which doesn't show any specific communication or interaction, but which still talks a thousand words just by the expressions of the people in it.
About the colors, though one element is the color theme, saying something about the time the photo was shot, I also think that the colors take the focus away from the elements in a photo, which otherwise would be central in the timeless photo. Colors are a crucial part of the photo, and often play a big role in the message being told. For example, photos with a lot of blue, and muted red or orange, are considered cold, while the opposite is considered warm. Colors are also used to convey a certain mood, which also can take the focus away from other elements of the photo. Black and white photos, tend to allow the subjects, shapes and forms be dominant instead.
But what about you? What do you consider to be a timeless photo? Do you like them? What would you consider, when or if you would take a timeless photo?