Tutorial: the paradox photo (the “Droste effect”) with Gimp and MathMap

Published by TheJoe on

Estimated reading time: 4 minutes


This article was published more than a year ago, there may have been developments.
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Today's tutorial is a cross between photography, graphic and Mathematics. Photography because we start from a real photo, and a good photograph is the beginning of a good job, graphic because of the various tweaks that as we make any and Mathematics because the effect scomoderemo today follows strict mathematical rules, nothing is left to chance. For this tutorial we will use Gimp and its plugin MathMap.

Some of you may have already heard of the “Droste” the “Droste effect“. For those who still do not have any idea what I can explain it as a “paradox photo“, a picture that contains a copy of itself, always smaller up to reach infinity. The same effect that we see when we mix two mirrors, we would see if we were invisible frames infinite. I leave space for images that, As is well known, worth a thousand words (because I can not really explain it in words). Here are some examples:

a picture of a picture of a picture of a picture of a picture of a picture of you
The scream.. Joe
Droste and Lomo

Let's start by opening a picture that might lend itself to the composition, flickr is the hottest topic la bocca aperta, but also the’camera lens, a framework supported, or any other person who can be “of course” removed the central part. For the occasion, I took a picture right now.

The end result will be this.

Voucher, I see you

To begin with we will begin to remove all contents enclosed between the index finger and thumb: the eye and the whole surrounding skin. We will use the tool “Intelligent Scissors.

Once you select the part to be removed click with the right on the level “Background” (yet the only) in levels and tab selectAdd Alpha Channel“.

And delete the selection pressing “Ctrl + X“.

At this point, as you can see from the last photo, we note that the effect “pixel” (the alias) is clearly visible on the edges just deleted. The following steps are used only to “smooth” the angles of the edges, and disregard Droste effect. Essendo procedure very simple, I will not bother with screenshots.

We begin selecting the interior of the “hole” with the tool “Selecting fuzzy.  Then broaden the selection di 3px, click on “Select” – “Enlarge” and insert the value 3. Now we go on “Filters” – “Blur” – “Gaussian” and insert a blur radius of 5px.

Look here:  Tutorial: flame text / smoke with Gimp

The result is almost imperceptible, but you will clear quickly changing from one photo to another of this article.

Ok, Now to the fun part. Open the main window of the plugin MathMap: “Filters” – “Generic” – “MathMap” – “MathMap“. Click You tab “Settings” and deflagghiamo “Auto Preview“. Then click its “Filters” – “Map” – “Droste“.

Clicking on the button “Preview” we see a’low-resolution preview the final result. You can, however, change some parameters (being the “Droste effect” a mere transposition mathematics to photography), and we can do it in the tab “User values“.

In this case I increased at high zoom and I reduced certain points in the field “Inner radius” shown him to be a larger part of the rest of the face. My advice is to experience, if the result does not satisfy us is more than necessary continue to experiment.

The tutorial could also end here, but it would not be fun, and then I thought about putting another effettino simple to give a touch more “dark” the photo.

Duplicate the layer (still the only) clicking on the button “Duplicates level” in the tab, note, levels. Desaturiamo the newly created layer (“Colors” – “Desaturation” and we see it in black and white) and apply a blur of 100px radius (“Filters” – “Blur” – “Gaussian“, insert the value 100px).

Change the mode level just blurred by “Usual” a “Multiplier“.

And here is the final result.


I keep this blog as a hobby by 2009. I am passionate about graphic, technology, software Open Source. Among my articles will be easy to find music, and some personal thoughts, but I prefer the direct line of the blog mainly to technology. For more information contact me.


lucasi · 16 February 2013 at 8:11 PM

I would like to know one thing if and’ possible: I noticed that there’ also opizione “animation” , but I could not figure out how to use it, ie’ I click on , I create the animation frames, but there is no '….you know how it goes set?


dario · 7 May 2012 at 10:19 PM

alright thank you very much!:-)

dario · 9 April 2012 at 4:49 PM

Hello, Now I tried to do it myself but the filter must be completely at random:(
That is the point which makes the repetition is not the transparent part but the center of the image.. What's wrong?

This is the original image:
This is what I get:


    TheJoe · 12 April 2012 at 4:01 AM

    Haha!! Carina the photo where you started, But I have a few observations:
    1_ Tries to put the part of the image that you've removed the center of the whole composition. Your initial image should be more or less like this:

    2_ Try to imitate you these coordinates, I think it is correct for the job you want to do.
    Coordinate droste

    Let me know if you have any other problem.

voucher · 21 February 2011 at 6:57 PM

mi piace 🙂 ..credo proprio che ci proverò!!XD

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