Creating anaglyph images
The basis of this text is taken from:
You will need:
The Photoshop Process
A pair of stereo images.
3D glasses with one red and one blue lens. The red lens goes over the left
Note: Manipulating the image to produce an anaglyph will be easier
to do if you are only working with the thumbnail. The smaller file will
take less time for Photoshop to manipulate. Additionally, errors due to
tilting of the photo will be less magnified over the small area of a thumbnail
versus the relatively large area of the entire overlapping area.
Once in Photoshop, open the left and right images. To open
a "tiff" file scanned in by a Macintosh, or a PC with a program besides
Photoshop, use the open as command under the file menu.
a) Verify that the background is white. To do this check under the
palette, which is on the right side. There are two overlapping boxes,
one is white, the other black. Click the white box. You should verify that
the colors to the right of the box are light. Now click the black box and
verify that it darkens the colors significantly. Finally, click the white
box again. You want the background to be light. Otherwise the images
will come out reversed.
If the scanned photo appears to be significantly darker than the original,
you may lighten the image using the brightness command. To lighten the
image, check under: image/adjust/brightness. Be careful when lightening
not to delete information from the scan. Too much lightening may eliminate
important geologic information. If you do any image adjustments, make sure
you do them to both images.
Convert the right image into RGB (red, blue, green) mode
Under the channels on the palette on the lower right of the
screen click on the word Red such that only the red channel is highlighted.
That is, click on the word red and not the dot to the left of the word.
If you have any problem doing this, or need to start over, click on RGB,
which should select all the channels. When you do this, click RGB and not
the dot to the left of RGB, then click the word Red. The end result
will be that the red channel under the channel palette will be highlighted
and all other channels will be clear.
Clicking in the box with the word "Red" selects the
Click on the right image and use Select/All from the menu. Then
use Edit/Cut. This will remove the green and blue information from
the right hand image and you will see a blank image on screen. Under the
channels palette you will see a red image remains.
Make the left image active. Use Select/All. Then choose Edit/Copy.
You can close the left image after using the copy command. The fewer files
open, the less time it will take for Photoshop to manipulate the images.
Make the right image active. Select Edit/Paste. The left
image is now cyane (which is a combination of green and blue). The right
image was made red in steps 3 through 5. By highlighting the red channel
on the right image and cutting all the material, you left only a red image.
By pasting in the gray tone left image into the right image with the only
the right image red channel selected, you effectively made the left images
the two remaining colors: blue and green.
In the RGB channel window, select the dot to the left of RGB.
This will allow you to see all the channels together and view the anaglyph.
However, because Red channel is still highlighted and none
of the others are, you will be able to manipulate the cyane image.
Clicking on the small box to the left of the "RGB"
box makes an eye appear to the left of every channel. This does not
change the selected channel (in this case, red), and will allow you to
view the composited RGB image.
Align the cyane image with the red image. To do this choose the move
tool, which is under the tools palatte. The tools palette is
the rectangular palette to the left of the screen. The move tool looks
like an arrow and a plus sign and is toward the top right of the tools
To significantly reduce the amount time to manipulate the images
by reducing the amount of memory needed by the computer do the following:
Once the red and cyane images are roughly aligned, close all other images
but the anaglyph image.
Use the draw rectangle tool and make a box slighly larger than the
overlapping cyane and red area.
Select all the color channels by clicking RGB on the channels
palette. All colors should now be highlighted on the channels palette.
Use the Select/All command. Then choose Edit/Copy.
Open a new image under File/New. A window will appear with the dimensions,
size, and type of file to open. It should be the same as the area just
copied. If it doesn’t say RGB then that means that not all the channels
were selected. If it does not say RGB, close the new image and go back
to step (b). Remember to click RGB and not the dot to the left of
Select the new image and use Edit/Paste.
You can now close the old anaglyph image without saving it because
you have all the necessary information on a new, smaller image.
Flatten the image under Image/Flatten image
Save the anaglyph image as a tiff file: filenamesp.tiff
Copy the thumbnail selection to a new file using the above procedure (a-h)
for selecting, making a new file, pasting, and flattening. Remember to
select an area slighly larger than the actual thumbnail because you will
be moving the right image around slightly. Save the thumbnail as: filenamet1.
Save repeated thumbnails as filenamet2, etc.
i) Line up the cyane image with the red image so that the overlapping
of the two images appears to be close to a gray scale photo. Then move
the cyane image slightly to the left of the red image.
To manipulate the cyane image to produce an anaglyph:
Select the red channel under the channels palette. To do
this, click RGB, then Red, then the dot to the left of
RGB. In this way, you will be able to see the red and cyane image together
but be able to move the cyane image.
Use the move tool to line up the cyane image with the red image.
They will be lined up when the combined image looks like a gray scale image.
Then move the cyane image slighly to the left of the red image.
For photos with significant elevation differences, such as mountains, or
gorges, line the images up at the lowest elevation. Our experience has
been that, at the lowest elevation, the cyane image should be about 12
pixels to the left of the red image.
-For the cyane image, light parts of the photo, such as roads, will
appear red when not lined up with the red image. This is because the red
from the right image is showing from beneath the cyane image.
-Conversely, dark parts of the photo, such as shadows, will appear cyane
when not lined up with the red image.
-Therefore, when lining the cyane image to the left the red image, the
roads will appear red and be to the left.
-Dark parts of the photo will appear blue when moved to the left of
the red image.
To get a reading on what a twelve pixel difference is:
ii) Select pixels under units and rulers, which can be found
iii) Check the spacing between the cyane and red image.
-Line up a man made structure such as a road or a field
-Using the draw rectangle tool, measure the distance between
the cyane and red image by drawing a box between them. Remember: light
images such as roads should will be red and to the left. Dark images such
as shadows are blue to the left. If you get confused as to which should
be left, line the cyane image up with the red image then move the cyane
slightly to the left, this is the correct placement of cyane.
iv) Click under the information palette on the upper right of
the screen. This will tell you the size of the area selected. You are shooting
for a separation distance between the red and cyane images of about 12
pixels at the lower elevations.
v) You can move the cyane image very precisely by selecting Filter/Offset.
vi) It is very important that you line up both images equally in the
horizontal direction. There should be not vertical offset.
To rotate individual channel
Highlight channel to rotate. That is, if you want to rotate the red channel,
click on the word red on the channels pallete.
Under the Select menu choose all.
Make sure depressions such as streams and valleys appear low and hills
enter angle to rotate image
image is rotated about its center