The Open CyberHolographicTM Standard
Introduction:
A "normal" image is two-dimensional. All positions on the image can be located by their X and Y coordinates. A three-dimensional image
has another dimension, Z, which is required. In terms of your computer screen, X is horizontal position, Y is vertical position, and Z is the position into or out of
the screen. Getting that extra
dimension into an image is tough; usually it
takes two images from different perspectives
to accomplish that, but using two images
doubles the image overhead.
ChromaDepth®
3-D takes a much more efficient approach by using color to carry the Z position information. This is called encoding
depth into color. This Image Design
Guide will explain how you can design your
own images that will show great 3-D when
viewed with Standard Glasses.
There are two parts to the ChromaDepth®
3-D process: designing the colors of an
image according to ChromaDepth®
3-D, then presenting and viewing the image
with Standard Glasses. The first step - designing the colors of the image - is much easier than it sounds. First, you choose a color palette (go to the
Standard
Color Palettes page for a thorough primer on this). There are
different color palettes to produce the best holographic effects for a selected background color. There are probably an infinite number of color palettes that
could work, but the simplest and most dramatic is RGB
on Black. This stands for
Red-Green-Blue on Black Background. In
the ChromaDepth®
3-D process the color of an image element
and that element's immediate surrounding
color determine its Standard depth position. If we keep the background color constant around each image element, then the color of the element alone will determine its Z dimension.
Background Color and Color Palettes: The choice of background color is the most important factor in determining the colors which should be used to achieve ChromaDepth
TM 3-D and CyberHologramTM effects. The easiest and most commonly utilized background
colors are black and dark blue. The color palette, RGB on Black/Blue, apply to both of these background colors. If dark blue is used, it must be a very pure,
very dark blue. The effects will not be the same for a sky blue, medium blue, or other light blue. The reasons for this are explained in the section on Tint and Depth Position.
On
a black or dark blue background the
ChromaDepth® color palette uses red for the most foreground object, dark blue for the most background object,
and green for the middle-ground. The other colors fall in between according to the colors of the rainbow. (Thus one could use red, orange, yellow, yellow-green,
green, blue-green, blue, and dark blue, in order, from foreground to background). An infinite number of colors may be used to divide the space between red and
blue. Contoured or rounded surfaces can be shown by smoothly blending from one color to another across the surface. Be sure to use black patterns on the surface to help define its shape; see
Use of Black for details.
Another color model that is very effective on a black background is the 'Patriot' color model; Red-White-Blue on Black. See the
Standard
Color Palettes page for details.
When a dark blue background is used it is important to incorporate some black pattern on the blue in order to locate the background in depth space.
Without a black pattern the blue background seems to be undefined space; it occupies some nebulous 'back there'. The black pattern provides edges for your
mind to locate in space, enlarging the apparent depth. For more on the use of black and the importance of creating edges, see the section on The Importance of Black and How to Use it.
On
a white background the ChromaDepth® color palette is the compliment of the color model for a black background. This makes the key colors cyan,
magenta, and yellow (CMY; the compliments of red, green, and blue, respectively), so this is called the Cyan-Magenta-Yellow on White color model. (Our Crayon CyberHologramTM
page illustrates this nicely, with crayons
and crayon drawings!) The inverse color
function on many computer graphic design
programs can take a normal black background
ChromaDepth® colored image and convert it to a white background, CMY
on White ChromaDepth®
image. But be warned; although the CMY on White 3-D effect is as strong as the
RGB on Black 3-D effect, the images created with CMY on White sometimes may look unnatural. The RGB on Black color palette follows the colors of nature
and of normal artistic design, but try both color palettes.
Using Outlines as Local Backgrounds:
A very good way to simplify dealing with backgrounds is to use black or white outlines around image elements. This effectively gives each element its
own 'local background', so that no other color can contact the fill color which is inside the outline. The choice of black or white for the outline color depends on
the color model used: the outline color should be the same as the background color in that color model. The width of the outline needed will depend on lots of
factors, and can only be determined by a little experimentation. Using outlines as local backgrounds is especially valuable when creating
animations in which objects may pass over each other. The outlines keep general CyberHolographicTM weirdness from breaking out. (Of course, that can have its own appeal.)
Depth Cueing:
Using normal two dimensional depth cues in an image can dramatically augment the depth created by the glasses. These include shading for
roundness, perspective and forced perspective effects, overlap, changing size as depth is changed, including shadows of one object on another, and increasing
the brightness of colors as objects are brought closer to the foreground.
It isn't always necessary to change the
color of an object as it is moved closer or
further in depth. An object moving
from the background to the foreground could
be designed to increase in size as it moves
up the color palette from blue through
green, yellow, orange, and red. Once it
becomes red, you can continue to force the
apparent movement in depth by continuing to
increase the size of the object, even though
you are no longer changing its color.
The strong depth cue created by increasing
the object's size continues to fool your
brain into seeing the object move forward
even though there is no change in the Standard created depth. Similarly, shrinking the size of an object while smoothly changing its color from red down the rainbow to blue will make the object appear
to recede into the distance. Continuing to shrink the object after it has reached maximum blue will continue the illusion that it is moving away.
Combining size change with brightness variation can achieve even more dramatic results. Make the object darker when it is supposed to be far away
and brighter when it is in the foreground. There is an easy way to accomplish this if you use a 3-D rendering program like 3-D Studio, Lightwave, Wavefront, Truespace, Raydream, or Polyray: turn on
fog and make the fog color black. Experiment with the fog density and its near and far planes to get the effect you like.
With strong two dimensional depth cues it is even possible to keep the sense of real stereoscopic depth while mixing up the colors, such as placing an
orange object behind a yellow one by use of perspective and shadows. It does not always work, but it can be worth trying. Be aware, though, that if you try to
push this too far the effect may break down. Avoiding the Image Border:
The border of an image generally appears to be at the
middle-ground
position. Any object colored to appear at
middle-ground or deeper can be clipped by the border without any visual problem; it looks like the border is a frame above the object, like it is in a shadow box.
Any object that is colored to appear closer than
middle-ground should be kept away from
the border because it will appear to
snap down to the border where it touches
it, losing the depth effect
(incidentally, this is true for all 3-D
processes, not just ChromaDepth®
and CyberHolographyTM). Adding a red or black border around the image can reduce this problem. In a moving image a red
object can move off-screen across the border if it moves quickly; your mind doesn't have time to figure out that crossing the border was a problem. Handling Highlights:
In
two-dimensional art, highlights from shiny
surfaces are normally shown by a white spot
or white starburst. This causes a problem
for ChromaDepth®
images because the color white tends to the
middle-ground of the image. This means that a white highlight on a blue object will look like it is floating off of that
surface, while a white highlight on a red surface will look like a bright point inside of the red surface. Highlights can
be used with ChromaDepth®, but they usually aren't colored white.
There are two main methods for showing highlights, and they can be combined in different amounts according to taste. The first approach is to select
the highlight color to be slightly closer than the surface it is on.
Here is how it works: the highlight on a
surface should be just slightly closer than
the surface, so it is necessary to use
highlights which follow the ChromaDepth® 3-D color/depth palette. We have found that using a color which is five (5) percent closer (closer means 'towards red') than the highlighted surface
is quite effective. For example, if the scene has been divided into twenty depth zones, a five (5) percent closer highlight would use the color of the next closest
depth zone. For one hundred (100) depth zones you would move closer by five (5) depth zones for the highlight. For more information on the color models see our Color Palettes page.
The second method is to keep the color the same as the surface, but to increase the brightness. This works well for TV and video, since the main object
colors need to be slightly muted (by adding black to shade them down) to keep them 'NTSC legal'. NTSC illegal colors 'bloom' on the screen, blurring past their
intended boundaries. This is fine for a highlight, so using NTSC illegal color brightness for highlighting works well to emphasize the extra brightness of the
highlight. With a little finesse, these two approaches can be combined with good results. The Importance of Black and How to Use it:
Black is extremely useful to the CyberHolographicTM artist. Here at Chromatek we say that 'black rides with the color it is on'. If you put a black spot
on a red area the black spot will appear to be at the same forward depth position as red on black. If you put a black spot on a blue area the black spot will
appear to be at the same background depth position as blue on black. Wherever possible, black should be used to outline colors which are on a
black or dark blue background. In a similar manner, white should be used to outline colors against a white background.
When the human brain compares the
differences in the images of a stereo pair
in order to determine what depth should be
perceived, it is the edges of objects and
other high contrast vertical features which
are compared. If you want to blend colors
across a surface to show roundness or
bending, it is very effective to add some
black lines into the surface to provide the
edges that convey the depth. For example, if
you want to show a ball that has roundness,
you can blend from red at the closest point
around to yellow at the edge, then add black
shading or crosshatching lines as would
normally by used to indicate roundness in a
two dimensional image. If the weight, or
thickness, of these black lines is adequate,
the lines will allow your mind to see the
height differences by the color blending in
a very effective manner. (Very fine black
lines may blur and disappear when viewed
with the Standard
Glasses. This is less likely with High
Definition Glasses.) Tint and Depth Position:
In the jargon of color, tint refers to taking a pure color and adding white to it. The resulting lightened color is a tint of the original. Tints can be used to
broaden the range of colors which appear to lie at a given depth position and to give textured effects to surfaces. Here is the lowdown:
We will first presume that we are working with a black or dark blue background. Under these circumstances a white object will appear to be in the
middle-ground position, about equally spaced between the foreground and the background. Adding white to any color 'pulls' that color toward the
middle-ground.
The degree to which the color is moved toward
middle-ground depends on the amount of white added to it. A little white only moves the color a little, much
white moves it far. Since the colors are pulled toward the
middle-ground, each color reacts to tinting in its own way. Reds and oranges move further away,
since they are forward of middle-ground. Yellow and yellow-green don't move much since they are already about at
middle-ground. Greens and blues move
closer with tinting, since they are normally in the background, behind
middle-ground. All colors end up at
middle-ground as they are tinted completely to white.
An extremely effective use of tint is to add texture to a dark blue background by tinting areas, making them lighter blue, to show raised portions.
A surprisingly small amount of added white will result in definite and pleasing depth change for blue. This can be easily accomplished in most graphics programs with the emboss
function if you have control of the highlight and shadow colors. Don't forget to include some black in an embossed blue pattern to help define the location of the darkest blue. Shading and Depth Position: The opposite of tint is shade; a shade of a color is created by adding black
to a pure color. Shading a color tends to move that color further away, in proportion to the amount of shading, regardless of whether it is a foreground
color or a background color. A dark shade of red won't move all the way back to the position of blue, but it will appear deeper than a bright red. The reason that
shading creates this effect probably depends on our familiarity with shadowing to show roundness. Use shading with care; if an image element's color is shaded
darker than the shade of its local background, then the background color will predominate in determining its perceived depth position. Color Quirks:
Red on yellow, with no black border between them, has an ambiguous depth position. It tends to look like the red is inside of the yellow area, down
about at middle-ground. A black border restores the colors to their expected positions. Red on green can have the same trouble as red on yellow if there is
no black border separating them. The controlling factor is the brightness of the green. A bright green will behave more like yellow, a dark green will behave more like blue.
Red on dark blue works without a black border. Light blues, or light tints of other colors, can produce a similar effect to yellow's, so use a black border
whenever there is any question. Magenta on black typically looks like a crisp, red object surrounded by a fuzzy blue halo. We don't recommend using magenta unless you are seeking that kind of effect.
Creating Readable Text:
Black on white is the normal choice for
text, but when using High Definition Glasses
or Standard Glasses this combination is singularly difficult to read . The
choice of font and size is important, too. We recommend Arial font, size 8 to 12 point, bold. We recommend any of the following color combinations for good readability:
1. Black or dark green on light cyan ([R,G,B]= [204,255,255]):
(Easy on the eyes, both with and
without ChromaDepth ® Glasses. It also prints well.) 2. Green on dark green background:
(This is
the easiest color combination on the
eyes, both with and without
ChromaDepth ®
Glasses. It does not print well, though.)
Light Green on Dark Green
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3. Dark green or black on green background:
(Also easy on the eyes. It prints better than number 1, above.)
Dark Green or
Black on Green
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4. Red text on black background: (This is dramatic, but can be hard to look at for a long time.) 5. Black text on red: 6. Magenta on white: 7. Cyan on white: 8. White on magenta:
Above all, nothing can take the place of lots of experimenting!
NOTE:
ChromaDepth® and
ChromaDepth® 3-D are both
used to refer to the process of
coloring images according to
ChromaDepth® 3-D image design criteria, also called the Open CyberHolographicTM
Standard. High
Definition and Standard refer to the unique and revolutionary micro-optic glasses manufactured by Chromatek Inc. which are used to
see the holographic effects of CyberHologramsTM
and Standard images.
ChromaDepth®, Standard, CyberHologramTM
and the grammatical variants of these terms are trademarks of Chromatek Inc., with all rights reserved.
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