Creating
3D Effects
(please
refresh this page often)
Introduction: Two images placed side by side will create a
3D effect if stars or nebula regions are shifted in one image relative
to the other, and if you then cross your eyes when viewing.
Examples of this effect can be found in several images on my website,
including the the Orion Nebula,
the Elephant Trunk,
IC1805,
and the Cone
Nebula. The inspiration for making 3D astrophotography images
comes from an article in
Sky and Telescope (December 2003), which featured the 3-D work of Akira Inaka.
Many have asked me how my 3D
images
were created, and specifically how I achieved the shift in
Photoshop. The technique is very easy and is described below.
The
following directions apply to users of Photoshop:
1. Open your image in Photoshop
and convert to 8 bit mode (necessary for using the "distort" function).
2. Orient your image vertically, so that it is taller than it is
wider.
3. Duplicate your image into another layer.
4. Increase your canvas size to accomodate the two images, and
place them side by side.
5. You will now only work on the right hand image, leaving the
left hand (original) image untouched.
6. To bring a star into the foreground, it must be shifted to the
right. To place it into the background, it must be shifted to the
left. The use of the "distort" function makes this easy to
accomplish (see next step).
7. Identify a star that you wish to shift. Encircle it
using the lasso tool with a feather of 5 pixels (experiment with
this). Go to "Filter, Distort, Shear". Adjust the vertical
shear line as desired (i.e., move to right or left). The more you
move the line, the more shift you will create. Experiment with
this to achieve the desired effect for a given star or nebula field.
8. You may wish to encircle the perimeter of a shifted nebula
region and apply a less aggressive shift to this area, in order to
achieve a pleasing transition between shifted and non-shifted regions.
The technique takes practice but is not difficult to master. Have
fun with it!
Steve
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