Create an Image with the Droste Effect

YOU’LL NEED THIS

PHOTOSHOP OR GIMP

Various Photoshop subscriptions available from www.adobe.com, or grab Gimp for free from www.gimp.org.

YOU’VE SEEN THE DROSTE EFFECT MANY TIMES, probably without knowing what it’s called. That’s OK, we didn’t know it was named after an obscure Dutch chocolate company that used it in its advertising either, but now we do. The effect is a recursive one—a picture within a picture within a picture, getting smaller each time. A bit like standing between two mirrors and watching yourself endlessly repeated to infinity. Or at least until the image is so small it can no longer be recognized.

There are two main types of Droste image. The simplest repeats an image in something like a photo frame or painting on a wall, while a more complex variant traces a line between the recursive images for a vortex-like result. There was once a Photoshop plugin named Pixel Bender that made the creation of these images easy, but it was never updated to work past the CS5 release. However, there is another image-editing app, one whose name is rarely spoken: Gimp. It’s free, so go to www.gimp.org, install it, then come with us down a path less well trodden.

1 FIND A PHOTO We’re actually going to start in Photoshop, because we know it really well, only using Gimp for the final transformation, but you can do everything in Gimp if you’re confident. It works best with a photo of something circular, so go out and find a storm drain outlet, a train tunnel, a barbecue smoker, a flower, that sort of thing. We used the end of a camera lens for our shot. You can do this with someone’s face, if you photograph them with their mouth wide open, or maybe with a great big close-up of their eye, but be prepared for a horrifying result. Once you’ve got an image you’re confident can be twisted into a recursive helix, open it in Photoshop, and set about removing not only the background outside the circular part, but the inside, too [ Image A].

2 TURN ON TRANSPARENCY

To get the transparency, double-click your background layer in the Layers palette, renaming it to something like “Layer 0,” then create a new layer, and place it behind Layer 0. When you’ve made your selection, hit “Edit > Clear,” and a transparent hole appears, rather than filling it with the background color, as would have happened if we hadn’t added the layer. Don’t flatten the layers. Save your newly cut-out image as a TIFF, ensuring you check the “Save Transparency” box on the TIFF options window.

3 INSTALL MATHMAP PLUGIN

To get the Droste effect, you need a plugin. The one you want is called Mathmap, and it’s on the Gimp Plugin Registry. Google is your friend. Once you’ve got it installed, there’s another hurdle to jump—the plugin needs to be told what to do. There’s an 11-year-old discussion thread on Flickr by software engineer Josh Sommers, in which he posts precisely what you need: a complete Droste effect Mathmap recipe to copy and paste. Here’s the link: http://bit.ly/2CSzvFb. And maybe find a way to thank the man for his work, too.

4 PASTE IN CODE

Copy the recipe—it’s huge—then open Gimp and your image. Head to “Filters > Generic > Mathmap > Mathmap,” and paste the code into the Expression window that opens, making sure you completely replace anything that’s already there. Immediately save the new filter, so you don’t have to paste it in again, then hit “Preview.” This gives you an idea of the end result with the default settings.

5 EXPERIMENT WITH VALUES

We’re not going to leave the settings at their defaults, though. Move to the “User Values” tab [ Image B], and play with the sliders, noting the effect they have on the preview window. You’ll always have a flat edge somewhere on your image, so it’s worth adjusting the “Inner” and “Outer Radius” settings, so that this intersects with the edge of the image area, making it look as if the image continues outside the frame, rather than having a sudden flat cut-off. “Periodicity” affects how tightly wound your spiral is, and can undo the work you’ve done with the radius, meaning you have to go back and fix it. “Strands” changes the

number of spirals created, making the problem of keeping the edges lined up with the sides of the image more complicated [ Image C].

6 MORE OPTIONS

The next slider is “Zoom,” and you can use this to cut off any flat ends, as well improve the composition of your helix. “Rotate” does what you’d expect, while “X” and “Y Shift” move your composition against the background. “XCenter” and “YCenter Shift” are more interesting, adding a 3D-like perspective shift. The other options have very specific uses, and don’t bring much to an image if you’re looking for a simple recursive spiral. The exception is “HyperDroste,” which adds a cool fractal effect you may like.

7 FINAL TWEAKS

We went back to “Settings” to mess with the “Edge Behavior” buttons before hitting “OK,” as they add background interest. On a 20MP starting image, it can take a while to process the effect— using a Core i7 overclocked to 4.1GHz, we still had plenty of time to check Twitter while it was chewing through data. And there you have it, a recursive helical Droste effect.

8 ALTERNATE STYLE

For the simpler type of Droste image, in which a picture appears multiple times inside itself, choose an image with a rectangular frame or window in it, then copy the entire image before selecting the inside of the frame or window. Use “Edit > Paste Special > Paste Into” to make the image appear inside the selection, shrinking it down and rotating with “Edit > Free Transform” [ Image D] as necessary. Doing this creates lots of new layers with masks on them, so you need to flatten the image before exporting it. The resolution of your image dictates how far you can go; shrinking the image each time eventually turns it into an unrecognizable blur.