Creepy Old Changing Photos

[Smokey596]

Saw these in an antique mall yesterday and was very intrigued! When you shift your view of the photo, it changes back and forth from normal to creepy. I tried to find some information about this technique online, but I have no idea what it's called or how to describe it to search for it. Can anyone tell me about how these were made. And why? Thanks!

[KC]

So, so, so cool!!!!  have to search this out! 

[cogar]

I can tell you how they were made but I don't remember the name of the process.

It is similar to a hologram .... but holograms ar 3D.

In essence, there are very, very fine "V" ridges on the print medium ..... and 1 of the images is printed on the "left" side of the "V" ..... and the other image is printed on the "right" side of the "V".

Thus, if you are looking from the "left" side of center you will see 1 image. And looking from the "right" side of center you will see the 2nd image.

There were a lot of "novelty" items (like key-chain fobs, etc) in the 70's (I think) that had those "kinda" images on them.

[mart]

There is a name for these but cannot remember what it is !!

[Rauville]

There is a name for these but cannot remember what it is !!

Here's what we remember.
http://www.didik.com/vv_his.htm

I also thought of a much earlier technique.
http://en.wikipedia.org/wiki/Anamorphosis

Update: Nice selection here. (click on your favorite)
http://www.theghoulishgallery.com/gallery-flash.htm

[Smokey596]

Lenticular and/or anamorphosis! Thank you!

Now, when I search for "creepy lenticular photos" I get a lot of similar items but also horror props, Halloween decorations, etc. What I am wondering is if photos like the ones I posted were actual family members and were made this way intentionally for some reason. Or are they simply random portraits turned creepy just for fun? And how old would they be then? It looks like the lenticular process dates to the 1930's but anamorphosis goes back quite a bit farther.

[mart]

Its possible these are not as old as they appear !!  Those frames are pretty new and the way the image is highlighted I think it would have been done with pretty modern photography !! Do they have dust covers on the back ?? Can you take a pic of the back of one of them !!

[Smokey596]

Its possible these are not as old as they appear !!  Those frames are pretty new and the way the image is highlighted I think it would have been done with pretty modern photography !! Do they have dust covers on the back ?? Can you take a pic of the back of one of them !!

I can't tell you any more about them, unfortunately. They were in a display case at the antique mall and I took the photos there through the glass. Maybe next time I'm there I will ask to see them outside of the case.