Create Stereographic Projections in Photoshop & GIMP

Creating Stereographic Projections in Photoshop or GIMP

Perhaps you've encountered a unique panoramic photograph resembling a planet or globe? These are known as stereographic projections. Don't be discouraged if the term is unfamiliar; it simply describes a distinctive photographic effect that often evokes a sense of wonder regarding its creation.

The Basics of the Effect

The process of generating this effect is surprisingly straightforward, though not immediately intuitive. A panoramic image serves as the ideal starting point for this transformation.

Many contemporary digital cameras include a built-in panorama setting. If your camera lacks this feature, you can capture a series of overlapping images and then stitch them together using software like Photoshop. Several dedicated panorama stitching tools are also available.

Images featuring prominent vertical elements and a relatively consistent horizon or ground line – such as those including buildings or a river against a sky – are particularly well-suited for this technique. Crucially, the left and right edges of the original photograph should exhibit strong similarities to minimize visible seams in the final projection.

Step-by-Step Guide: Photoshop & GIMP

Begin by opening your chosen image in either Photoshop or GIMP.

Next, the image needs to be converted into a square format. In Photoshop, navigate to Image > Image Size, disable the Constrain Proportions option, and ensure the height and width are identical. (Within GIMP, use Image > Scale image and unlink the Width and Height parameters.)

Now, rotate the image by 180 degrees. In Photoshop, go to Image > Image Rotation. (In GIMP, use Tools > Transform Tools > Rotate). This step is optional and may require experimentation; the top portion of the image will define the inner circle, while the bottom will represent the surrounding environment.

We are nearing completion. Apply the Filters > Distort > Polar Coordinates filter, selecting "Rectangular to Polar" in the dialog box. (In GIMP, the filter is found under Filters > Distorts > Polar Coordinates).

The effect is now achieved. Depending on the original image, some minor adjustments may be necessary. A common issue is a visible seam where the original left and right edges meet.

Addressing Visible Seams

Here’s how to quickly eliminate any noticeable seams:

Duplicate one edge of the image and paste it as a new layer above the original.
Position the duplicated edge on the opposite side of the image. Don't worry if a hard joint is initially created; this will be addressed in the next step.

If the edges appear similar, blend the harsh seam. Add a layer mask to the duplicated edge layer and paint with a soft black brush on the mask. This will reveal the underlying layer and create a smoother transition. Avoid overdoing it; stop as soon as the seam disappears.
Repeat these steps to achieve a seamless result.

Finally, rotate the image and adjust the contrast to enhance the "otherworldly" appearance. Experiment with different variations and color adjustments to personalize your image.

We are eager to hear your feedback on this effect and see the creative results you achieve!