"The Very Eye of Night"
This piece is a staple for video technology. She essentially created a modern day green screen effect by either layer by layer cropping out a dancer or group of dancers and placed a still image in the background. (in this case stars.) I would venture to say that it looks like there may even be some form of glow on the objects which i have no clue how that would be done back in the day.
Today programs such as Final Cut Pro, After effects and even PD and Max MSP are able to chroma key/ Luma key an image to allow transparency. What this does is it takes away a certain portion of the image, whether it be the green solid, blue solid or the white or black portion of an image, and allow another image below it to be seen. Today, this is a very common effect and due to technology, is made possible to every VJ live. Such Cool technology.
