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Note: A cross-eye stereoimage contains two images and requires you to cross your eyes and stare at them until a third image appears between the two. With your eyes still crossed, focus on that middle image and some depth should appear.
This is probably the only technique I use that I haven't been willing to share. However, I don't want to be perceived in a bad light either, so I'll share some simple techniques that I've learned over the years so that you can make your own. These aren't what I use, but they work.
Here's what we will be creating in this tutorial:
and
Both will be created using very different techniques, but equally simple.
When you look at something, your eyes do not see the same thing. Your left eye will capture a certain range of the object and your right eye will capture another range. Obviously there is a LOT of overlap between what your right and left eyes are viewing, but the differences are where the depth is captured. An image is a 2 dimensional object and in order to give it some depth, we have to create 2 images (one for the left eye, the other for the right) AND we have to "impose" some variation into each image. Remember, the 3rd dimension is created in the variation.
I am using GIMP 2.6.6 for this tutorial. Older or newer versions will work, but menu locations may be slightly different. This tutorial assumes the user has some basic knowledge of GIMP; however, I will provide enough screenshots and narrative that relative new users to GIMP should be able to accomplish the tasks will little trouble.
Let's begin!
Technique 1 - Manual shifting of layers
Step 1
To simplify things, I have prepared an xcf file for you to experiment with. Please download the file here: http://fencepost.gim...osseyeright.xcf
Open the file and create a duplicate of it (Image > Duplicate):
Arrange the two images, so that the crosseyeright.xcf file is on the left and the duplicated is on the right. Remember, we are creating a cross-eye stereoimage and the right eye will look at what's on the left and the left eye at what's on the right.
Here's what my two images look like (notice I've adjusted the out borders of the image window so that they are up close to the image edges. This will help with viewing.) If you look at them with crossed eyes right now, there is no depth. That's because they are exact duplicates....there is no variation. No variation = No depth.
Step 2
We only need to add in variation to one of the images. I like working with the crosseyeright.xcf (the image on the left side of your screen.) I suggest you do the same to keep up with my steps.
Select the Move Tool from the Toolbox:
and click on the "Green G" layer in the layer dialog window to make it active (highlighted blue in the screenshot below)
Now, with the Move Tool, click on the crosseyeright.xcf header to make that image active (the header is where the image name and other details are shown):
Step 3
Since your Move Tool is active, you can use the arrow keys on your keyboard to adjust the layers. With your Left Arrow key, click 6 times to move the Green G layer to the left as shown below. (If you cross your eyes, you'll see an immediate difference.)
Step 4
Next, make the Green I layer active and click on the crosseyeright.xcf image header to make the image active again, and using the Left Arrow key, click 3 times to move the Green I layer to the left, like so (again, if your eyes are crossed you'll see immediate results):
Do the same thing for the Green M and Green P layers using the Right Arrow keys as shown in the screenshots below:
Step 5
Now, do the same thing for all the red layers, but use the following settings this time (no screenshots included):
Red G: 6 clicks to the right
Red I: 3 clicks to the right
Red M: 3 clicks to the left
Red P: 6 clicks to the left
If you've done everything correctly, the Green GIMP should look like it's sticking out on the left side and moving towards the back on the right side. The Red GIMP should look like it's sticking out on the right side and moving towards the rear on the left side.
You're finished!
To combine them into one image:
On the crosseyeright.xcf file go to Layer > New from Visible
Then copy the new layer Edit > Copy
Paste it into a new image (Edit > Paste as new image). We'll call this the New Image.
Then, go to Image > Canvas size and set the width to twice the width of your image (I usually add 15-25 extra pixels to allow for a separation between the two images) and keep the height the same as the original image.
Now, click on the duplicate image (the left eye, if you will) and choose Layer > New from Visible
Then copy the new layer Edit > Copy
Select your New Image and go to Edit > Paste as New Layer.
Select the Move Tool, activate the New Image and, using the Right Arrow Key, move the top layer over to the right side of the image.
Save!
Technique 2 - IWarp shifting of layers
Step 1
Take any image you want to add depth to and set it up so that you have 2 of them. I'm not providing a download for you on this technique. I've set mine up so that both of my images are combined into one main GIMP window. Since I'm doing that I want to limit my work are to the only the left side and I used my rectangle selection tool to create a selection (highlighted in red below).
Step 2
Now go to Filters > Distorts > IWarp...
and when the IWarp window appears, I used the following settings highlighted in red on the right side of the screenshot. You experiment with the settings as you would like.
Now, on the IWarp preview window, click with your mouse button and drag in the directions shown. (Make sure you experiment with where you click and drag and the amounts used. Mine is only an example for this tutorial.) Don't drag up/down only left or right. If you drag to the right, the image will appear to sink in. If you drag to the left, it will appear to come forward. If you make a mistake within IWarp, click the reset button start again. Don't try to distort the image too much. If you're happy with what you've done, click OK to accept the changes.
You are finished! Here's the final version again for your viewing pleasure....
I hope this tutorial has been helpful. Let me know if you have any questions or need clarification. Make sure you show me your results.
Cheers and Happy GIMP'ing.
Art
