The megalethoscope is an optical apparatus designed by Carlo Ponti of Venice before 1867. The megalethoscope is the evolution of the alethoscope, invented by Ponti between 1859 and 1862.

In it, photographs are viewed through a large lens, which creates the optical illusion of depth and perspective. The albumen photographs are either backlit by an internal light source—usually an oil or kerosene lantern—or lit by daylight admitted via a system of opening doors. Ponti and others produced specially prepared photographs for use in the Megalethoscope. The photographs themselves were translucent and were coloured and pierced to create dramatic visual effects, such as using backlighting to create the impression of nighttime.

The megalethoscope was and is often confused with the stereoscope which was of a different design and effect.
However, the megalethoscope and the alethoscope are capable of a certain illusion of relief, that uses chromostereopsis.

The Diagonal Method (DM) is a “method” of composition that I accidentally discovered in May 2006, doing research in relation to the (in photography known) theory of composition called the “Rule of Thirds”.
The Diagonal Method is not a (contrived) theory, but a discovery. It is not derived from the Golden Section or the Rule of Thirds.

The technical side of Diagonal Method is rather simple: each 90 degree corner of a work of art can be divided into two angles of 45 degrees. This dividing line is actually called the bisection line (a bisection is a line that divides an angle into two equal parts). It appeared that artists were intuitively placing details which they found important, on these lines with a deviation of max. 1 tot 1,5 milimetre.
I called this the Diagonal Method because these lines are also the mathematical diagonals of the two overlapping squares within a rectangle. People seem to look through pictures in the same way as the artist did; they follow the bisection lines or Diagonals.
 

The difference between the existing theories of composition (the Rule of Thirds and the Golden Section) is that the Diagonal Method is not concerned with making “good” compositions, but with finding details which are important to the artist in a psychological or emotional way. On this level the DM is completely subjective. It has nothing to do with placing lines or shapes in a certain location within a frame with the intention of getting a “better” composition. So we can use the DM to find out what the interests of the artist were. The positioning of these details is done in an unconscious manner. That’s why the DM is so exact.
Of course it is also possible to crop a photograph afterwards in such a way that details which are important to the photographer, are placed somewhere on these Diagonals.

The Diagonal Method: technical explanation

The 35 mm photographic frame is a rectangle with a ratio of 2:3. Within this rectangle you can draw two squares that overlap each other (see fig. 1). I discovered that artists like Rembrandt, famous photographers, but also amateur photographers, often were placing details like eyes exactly on these Diagonals.

fig. 1

To test this I used a transparency with just one bisection line (see fig. 2).

Because of the exactness of the DM it is necessary to align the corner of this sheet exactly with the four corners of the work of art that you want to test. (It is not possible to see whether a detail lies on a Diagonal, without such a sheet.)
Any position on the four diagonals could have been used to place details by the artist. The dots on the lines in fig. 3 could be such spots.

fig. 2

Details are often lying on the Diagonals with a accuracy of 1 to 1,5 milimetre on a A4 size picture. Precisely this precision was the decisive factor in my research. If the Diagonal Method would have been just as inaccurate as the Rule of Thirds, then I just would have thrown all my findings in the dust bin.
I searched for a theoretical explanation of the DM in books of art about composition but I did not find anything useful. Rudolf Arnheim mentions the square and “force lines” and “force fields” in his classic “Art and Visual Perception” but it is rather strange that he does not say a word about rectangular art. He only did research on square works of art.

fig. 3

Brian Thomas tested 98 famous paintings in his work “Geometry in Pictorial Composition” and found a lot of geometric forms in these works but he did not reach a conclusion concerning a particular method which was used more often than others.
My opinion about this kind of research is that it is unlikely that one would find anything conclusive. If I would not have done visual experiments, I also would have found nothing interesting. I did not start with a theory, but with looking and experimenting. Also it was not my goal or intention to look for geometrical forms in art or to find a new compositional method. (The experiment itself will be explained on this website later on.)

For me the important thing was that the DM actually worked, whereas the Rule of Thirds and the Golden Section seemed rather off. (Nevertheless, one can use the Rule of Thirds to avoid placing small and middle sized subjects in the center of the frame. But there is no exactness. Also, there are no studies in which the theory of the Rule of Thirds is proven.)

A new paradigm in composition
There is a most important difference between the DM and the Rule of Thirds. Concerning the Rule of Thirds, people do consciously place subjects like horizons and lampposts on the lines of the Rule of Thirds. I know, because many of my students tell me that they do this. Most of the time these parts are not particularly important, concerning content. On the other hand, photographers (unconsciously) place details on the lines of the Diagonal Method which have an important meaning in the narrative of the photograph, or are important to the photographer in a psychological or emotional way (and are immediately seen by the viewer).

This is the least understood aspect of the Diagonal Method, but at the same time the most important one.
It is, like someone from Vietnam told me, a “new paradigm in composition“. Using the Diagonal Method, one can detect for instance, things in which the artist was interested in or, see in a quick glance the most important details of a photograph or painting. This means that compositional arrangements are linked with content. This is new. The Rule of Thirds and the Golden Section are theories, and the theory is that the composition will get better if you place subjects on certain lines or cross points. Clearly, the narrow definition of the word “composition” is meant in these cases (see the section below). In addition, I found in my research that the Rule of Thirds and the Golden Section “do not work”, meaning that one can place subjects on certain lines, but this does not necessarily lead to a better composition (in most cases, it leads to a worse composition, because the overall intuitive framing of the picture is violated by a rational decision. The theories of the Rule of Thirds and the Golden Section are contradictory to rule No. 1 in composition: “The overall intuitive framing of a picture is always more important then the placement of details“. With the Diagonal Method, the overall intuitive framing and the placement of details are done at the same time, because both are done unconsciously. So rational manipulation cannot destroy the total composition. (Rational manipulation is sometimes necessary but the combination of intuition/feeling and thinking is always paramount in getting good compositions.) Therefore it is important that the placement of details is done unconsciously, as is the case with the Diagonal Method. (Of course, when a detail is just “off”, one can use the cropping tool “Diagonal” in Lightroom to correct this. But when you have to crop inches to do this, then something is not quite right and one can better shoot everything all over again or decide on a whole new composition.)

Does the DM gives a better composition?
That depends on which definition one uses of the word “composition”. In the narrow sense composition can be stated as “the arrangement of elements within a square or rectangle”. My opinion is that works of art could get somewhat better as a result of the use of the DM, viewed in this narrow sense. In my Master Classes “Composition in the Arts and Photography” I use a broader definition of composition: “the total design of a work of art“. In this sense the composition can get a lot better, because viewers will see immediately which details are important, concerning the meaning of the photograph or painting.

The very first photograph I tested was a portrait made by one of my students (fig. 4), and I was surprised, not to say shocked, that the Diagonal went right through the center of the pupil of the eye (yellow line).

fig. 4 (the cross point belongs to the Rule of Thirds)

Conclusions

–  We can discover hidden points of interest in works of arts (composition is linked with content)

–  All positions on all four diagonals are possible for placing details.

–  In landscapes and architecture there are often no important details so the DM does simply not apply.

–  The DM is mostly found in portraits and social photography.

–  The DM can be used to crop photographs afterwards.

–  Sometimes lines that are formed by things like arms are on or parallel to the  Diagonals.

–  In advertisements small things like watches or the eye of a model are often lying on the Diagonals.

–  Details which are important to the artist are lying almost always within 1 mm on one or more Diagonals

Edwin Westhoff

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