To convert a 2D image to 3D it must be displaced into left and right views, similar to those captured by a stereo camera. Photoshop can do this with a depth map we create. A depth map is a graphic grayscale image that has the same pixel dimensions as the 2D image we want to convert. The depth map tells Photoshop where each part of the 2D image should be located in the 3D space image.
It is the luminosity of the depth map pixel that tells Photoshop where to displace the 2D image pixel to. The brighter an area appears in the depth map the closer it will appear in the 3D image, it´s that simple.
The depth map and the 2D image are arranged in a ConversionSet, your project master file so to speak. It is a fixed file construction, meaning that you can only work within the layers given to you. You can not add, delete, swop or rename layers. Not if you expect Photoshop to process it.
A “real” ConversionSet is divided into Levels, each consisting of an image layer with a depth map layer on top. For this introduction however we will work in 1 Level only, that is in a ConversionSet containing only a Space layer (2D image) and a Space map layer (depth map), like the above.
To make a depth map we need to first establish what are objects and what is environment, called Space. The objects are selected and saved as a path. Then the large surfaces of Space are selected and filled with shades of gray in the Space map layer. Finally the selected objects are filled with gray color picked up where the objects relates to Space. Basicly.
There are two basic ways of filling the selected areas with gray color, gradient style and topography style. Together they enable us to deal with and control most scenarios.
Gradient style is the modern approach to depth mapping. It is fast, smooth and smart. Designed by and for the digital age. 2D3D has always been second to genuine stereoscopic 3D because 2D3D has detectable depth planes. Real stereoscopic 3D space images has an infinite amount of depth planes, I call this “maximum depth resolution”. By depth mapping gradient style we can create a 3D space image that has a “high depth resolution”.
Topography style was how 3D comics were made in the 1950´s and onwards, even today most 2D3D converters use this technique in one form or another. It is also called “cardboard cut out 3D” because the old masters literally cut out parts of the image, and manually displaced them sideways. Each plane being flat but separated from the others by depth. Today we only need to select the depth planes of an image, Photoshop can then produce the depth map and the 3D image for us. There is virtually nothing you can not do with this technique, as long as you have depth planes enough.
Photoshop can process your ConversionSet into a StereoSet. This too is a fixed file construction. In a StereoSet the left image is placed in a layer on top of the right, with an opacity of 50% for stereo window alignment, and all is selected for the after alignment crop. The stereo window is aligned by moving the left image sideways with the Move tool and arrows. Once the left and right images are aligned at the closest point that comes into contact with the stereo window (image frame) the conversion is finished.
To view your work in 3D Photoshop can process the StereoSet into a red-cyan anaglyph. When the process is done 3 files will be open, your ConversionSet, StereoSet and anaglyph.
If you are not satisfied, go back to the Space map layer in your ConversionSet to make changes. Then process again.
If you are satisfied, save these files with new names. They will be overwritten with your next project.
If you need a stereo pair for use outside the Photoshop environment, the StereoSet is split into a left and a right image.