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Creating a Stereographic Projection in Photoshop

Several years ago, I was introduced to a way to create cool and unique pieces of art from a photograph in Photoshop. This type of digital art is known as a stereographic projection or “little planet” and, while you don’t see too many people doing it anymore, it seems like it was kind of popular a few years ago.

To make this kind of art is actually pretty simple and requires only a couple of things: a great photograph and a copy of Adobe Photoshop or a similar image-editing program. The best stereographic projections use a type of picture called a 360-degree panorama. This means that the edge of one side of the panorama could be placed next to the opposite edge of the panorama and the two sides would form a continuous scene. These types of pictures are often created by standing in one place and taking continuous photographs while panning the camera in a 360-degree circle, then stitching the photos together in Photoshop or a similar program. Many smartphone cameras now have a panorama feature that makes this easier.

So what do you do if you can’t get a 360-degree panoramic photograph? There are two options: either fake it by editing the image you have, or mirror the image. I have done both, and both options can provide great results.

Faking It

First, I want to show you how to fake it. I’ll use a copy of my photograph, Hovenweep, taken at Hovenweep National Monument.

After opening the photograph in Photoshop, I will go to the “Filter” menu, scroll down to “Other,” and choose “Offset…” from the pop-out menu. In the “Horizontal” text field in the dialog box that pops up, I will type “1000” and click the “OK” button.

Offset Dialog Box

My image will now look like this:

I can now use the Clone Stamp tool to replace areas of the image along the seam so that the offset sides flow into each other without a noticeable difference. Since we are creating a stereographic projection the seam doesn’t have to be perfect, but I will still make it look really good. Once I am finished with that, my image will look like this:

Hovenweep after cloning

You can still see a couple of places where I could have tried to make it look better, but it will be fine in the final result. Now that I have erased the seam, I will go to the “Image” menu, scroll down to “Image Rotation,” and choose “180°.” Back in the “Filter” menu, I will scroll down to “Distort,” and choose “Polar Coordinates…” In the dialog box, make sure the “Rectangular to Polar” radio button in selected and click “OK.” My image will now look like this:

Hovenweep after polar coordinates filter

The last step is to resize the image so that is a square. Some people do this step right after using the Clone Stamp tool, but I prefer to do it last. When I do it earlier in the process, I occasionally get weird artifacts in my final image. To complete this step, I will go to the “Image” menu again and choose “Image Size.” In the dialog box, I will make sure the “Resample” check box is selected and the link icon between Width and Height is not selected. I will choose “Pixels” from the drop down menu next to Width. Then I will change the value in the text box next to Width to match the value in the text box next to Height, and click “OK.”

Image Size Dialog Box

My final image looks like this:

"Hovenweep Stereographic Projection" (2017) by K. Bradley Washburn

Although not perfect, my seam is now not even visible.

Mirroring

For this example, I will use a different image. I’ll open up a copy of my photograph Cottonwood Creek in Photoshop. The first thing I will do is go to the Layers panel, click the lock icon on the Background layer, right-click on the layer, and choose “Duplicate Layer.” I now have two layers, each with the Cottonwood Creek image.

From the “Image” menu, I will now choose “Canvas Size.” In the dropdown box next to Width, I will choose “Percent.” Then in the text field next to Width, I will change “100” to “200” and click “OK.” This will double the width of the canvas while keeping the height the same.

Cottonwood Creek after resizing the canvas

Using the Selection Tool, I will drag one layer clear to the right of the canvas and drag the other layer clear to the left of the canvas. Then, with just one layer selected, I will go the “Edit” menu, scroll down to “Transform,” and choose “Flip Horizontal.” This creates a mirrored landscape and my image now looks like this:

Cottonwood Creek flipped

With the top layer selected, I will now press “CMD+E” (Mac) or “CTRL+E” (Windows) to merge the two layers, and follow the steps I took above to rotate the image, map to polar coordinates, and resize to a square. My final image will look like this:

"Cottonwood Creek Mirrored Stereographic Projection" (2017) by K. Bradley Washburn

That’s all there is to it! With a nice photograph and a decent image-editing program anyone can create a stereographic projection.

This article is an updated version of an article originally published on Artistic Imposter Design.

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Image Resolution

Many people get confused when it comes image resolution and image size, and how they relate to the amount of pixels versus pixels per inches (ppi, also known as dots per inch or dpi). In my two-decade career as a graphic design professional, I have even known many professional designers who didn’t understand the difference.

Photoshop users have it easy. The Image Size dialog box automatically calculates the inches for you based on the resolution you need. The most important thing to remember when changing an image’s resolution from 72ppi to a printable resolution is to uncheck the Resample Image checkbox at the bottom of the dialog box. If the box is checked, you will pixelate your image and it will be unusable.

To figure out the measurement of a picture in inches, you will need to divide the number of pixels by the resolution. A 3000 × 4000 pixel image at 72ppi will be roughly 41.6″ x 55.5″. When the image resolution is changed to 300ppi, it will be 10″ x 13.3″.

When it comes to image size, the resolution is not important – the total pixels are. The resolution can be changed, but the total pixels need to stay the same to avoid pixelation. A 3000 × 4000 pixel image at 72ppi can be changed to 300ppi, but the 3000 × 4000 pixels must NOT be changed. There are techniques to get around this in a pinch, but changing the amount of pixels should be avoided unless absolutely necessary.

And remember…not all images need to be printed at 300ppi. 300ppi is the standard resolution for print, but it really depends on the project and the printer. Posters and similar items not meant to be seen up close can get away with as low as 150ppi. Also, anything larger than around 350ppi will increase your digital file size with no improvement in print quality.

This article is an updated version of an article originally published on Artistic Imposter Design.