Panama Pacific
International Exposition

ImageMap - turn on images!!!

How To Make Anaglyphs With Adobe PhotoShop

1) Scan your image into the computer. Use a reasonably high resolution so that a single image ("one eye" worth) will be large enough for the final anaglyph.

2) Make sure that the photo is square with the screen. To do this, use the "measure" tool to mark along the bottom edge of the entire stereo pair. You might want to change the magnification to 100% (menu: View->Actual Pixels) for this step to get the greatest accuracy.

3) Go to Image->Rotate Canvas->Arbitrary... and you'll note the tilt of the measure tool line is automatically entered. Click OK. The image will be rotated so it is perfectly horizontal.

4) You might want to crop the image at this point to get rid of any undesirable border. Use either the Crop tool or the rectangular marquis tool and the Image->Crop menu command.

5) Save the stereo pair to your disk as you probably want to preserve the original at this point.

6) Now select the left-hand image of the pair with the rectangular marquis tool. Carefully select only the image! Copy this image using Edit->Copy menu command (or command-key).

7) Make a new document File->New... and click OK. The new document should be the exact size of the area you copied (this happens automatically using the size from your copy command). This will be our anaglyph window.

8) Paste the left-hand image into the new document Edit->Paste.

9) Click back to your original stereo pair window. With the marquis tool still selected and inside the selected area, click and drag with the shift-key held down to move the selected area over the right-hand image of the stereo pair. You must start the drag before you press the shift key! This constrains the movement to exactly horizontal. If you press the shift-key before you move, you will add to the selected area. Note that we are moving only the selection area, not the actual picture. This assures us that the area we copy will be the same for the right-hand picture as it was for the left-hand picture.

10) Now copy the right-hand image (Edit->Copy), click to your anaglyph window, and paste (Edit->Paste) the right-hand image to this window. It will seem to erase the left-hand image, but is really creating a new layer over the original image.

11) Now we're going to change the colors of the black & white photograph. We need to be sure that we are in RGB mode. From the menu, choose Image->Mode->RGB Color. We want to retain our layers, so click "Don't Flatten" in the dialog box that appears.

12) Make sure your Layers palette is showing. If not choose Window->Show Layers from the menu. Select Layer 2 (the right-hand image) by clicking on it in the Layers palette.

13) Choose Image->Adjust->Levels... From the "Channel" pop-up, choose "Red". Type in 0 (zero) in both "Output Levels" boxes. Note that your image has turned cyan. Click OK.

14) Select Layer 1 (the left-hand image) in the Layers palette. Click the eyeball for Layer 2 to make it invisible so you can see Layer 1. Choose Image->Adjust->Levels... From the "Channel" pop-up, choose "Green". Type in 0 (zero) in both "Output Levels" boxes. Note that your image has turned magenta. From the "Channel" pop-up, choose "Blue" and type in 0 (zero) in both "Output Levels" boxes. Note that your image has now turned red. Click OK.

15) Go back to the Layers palette and click the eyeball for Layer 2 to make it visible again. Make sure Layer 2 is selected. We need to make this layer transparent so the red layer shows through. From the pop-up menu near the top left of the Layers palette, choose "Screen".

16) Since stereo pairs should only display horizontal displacement, we want to vertically align our images. Choose an object somewhere near the center of the image where you can see both the red and cyan images. With the Move Tool (the arrow) selected, use the keyboard arrows to eliminate any vertical offset between the images. You might want to have your magnification at 100% for this step. You should adjust the horizontal offset of the two layers such that the closest object in the scene is exactly matched. This will place that object in the plane of the display and everything else will be "behind" the display. You might want to do an additional crop of the image to eliminate colored borders.

17) Check out your image with your glasses on.

(Left eye = Red, Right eye =Cyan)

18) Save the image. If you want to preserve the layers, save it as a PhotoShop document. If you want to save it as a JPEG, you'll have to flatten the image. From the menu, choose Layer->Flatten Image and then you'll be able to save as JPEG.

© 2001 Exploratorium, 3601 Lyon Street San Francisco, CA 94123