Since way back in the 19th century it has been well known that it was possible, given the right conditions, to perceive differential 3D depth from 'prepared' 2D images. However, until fairly recently (the last 50 - 60 years) this was limited mainly to perception of monochrome 3D from pairs of stereo prints through optical viewing devices which were carefully arranged such that the two images were viewed as if superimposed. Then, since the 1950's, there have been various attempts to improve such perception, this having increased greatly in pace and variety of method since the advent of widespread digital image creation and handling. This means that, at the present time, there are at least six different modern methods of providing such 3D perception which are being marketed. However, it seems that there is still not a fully agreed understanding of exactly how perception of 3D depth is achieved within the human visual system.
This report first attempts to summarise the history of 3D perception from 2D imagery, then discusses & compares the various newer methods which are current. It then goes into more detail about a specific newer commercial method which is believed by the present author to be overall the best (Colorcode3D). Following on from this it attempts to provide a full explanation of why & how this method works so well (with several references to the mechanisms of human vision to which it is believed to be exceedingly well matched).