Persistence of Vision

Write down the key words and phrases that you’ve highlighted:

• "The human eye retains an image for a fraction of a second after it has been seen. If, in that brief time-space, one image can be substituted for another, slightly different, image, then the illusion of movement is created."
• "We look at a cinema screen is not a ‘moving picture’ at all, but a series of still pictures – 24 every second – shown in such rapid succession that our eyes are deceived"

Actual Definition
Persistence of vision is a commonly-accepted although somewhat controversial theory which states that the human eye always retains images for a fraction of a second. This means that everything we see is a subtle blend of what is happening now and what happened a fraction of a second ago.

What are the key words / phrases?

• Vision 
• Theory 
• Fraction of a second 
• Subtle blend  

My Definition
Persistence of vision is the theory that we see images a fraction of a second after they have actually gone. This links in with optical illusions as when you would see the next image the previous image would still be in your eyesight. Therefore it looks like the two images you are seeing are actually moving.

How It Works?
So, this is how it works. Your eyes and brain has a image delay for 1/30 of a second, however this can change depending on the brightness of the image. For example in the image below you are presented with a succession of images on a strip. if you move the strip slow enough then you will notice each particular image. However, if you move the image fast enough then you will see the delay of the previous image as well as the current image at the same time thus manipulating our mind that the images are in fact 'moving,' even though they are not. This also can be linked to films we watch daily. for example frames on this are shown as 60 frames a second, with are persistence of vision, we are tricked into believing that we are seeing a smooth free flow sequence even though most of the film is actually black. This theory also links in with the ideas of a thaumatrope and a roller as both have two images that manipulate are vision to make us believe that the image is moving however it is because the delay on the image which puts the two images together.

Bibliography 

Persistence of vision http://www.mediacollege.com/glossary/p/persistence-of-vision.html Assesed 28/04/17