1.2 Study of the colours and outlines of the selected image

The different objects offered by an image can be useful for a great many parameters, from a simple melodic line, or average structures to the global form of the piece which will eventually be elaborated. With the passing of time the experience we have gained has shown us that the architectures that project (thicker) colours serve better to work with a large number of voices, whereas the outlines, which are usually much thinner, are of greater interest as linear curves for one only instrument.

After an initial study of the original image and with the help of computer tools made for the purpose, we decide on a determinate number of colours and outlines which will eventually turn into the elements for the making of the musical piece. Once we have decided on what we want, we try to obtain it, though it is not always possible to achieve it. To do so we have at our disposal an endless number of filters of which we will say more in the following pages, as well as a determinate number of functions which render different kinds of readings. The combination of one thing and the other will lead us to the desired objective most of the times.

The procedure is as follows: we have the fractal image on a virtual plane and on another plane of a similar kind we have the encoding of a musical score in the shape of a graph paper. The vertical position on plane 1 would depict the different heights taking the base of the image as the deepest note; the horizontal line would depict each of the temporal units. On plane 2 the vertical position would depict each one of the voices, whereas the horizontal position, as on plane 1, would depict the temporal line in which each step would represent a minimal figure (e.g. semiquaver). The plane of the original image contains a number of squares (X,Y) plus information regarding the colour. The plane of the encoded musical score contains the number of voices (one for each horizontal line), a number of boxes as minimal units, and a colour as well (the use of the latter may vary: type of material, especial subarchitectures or other…). We will call the plane of the original fractal image plane 1 (P1) and the encoded score one, plane 2 (P2).

The dimensions of P1 correspond to a pre-assumed musical logic which has to do with the MIDI standard. Within MIDI systems, heights are regulated by numerical values which range from 1 to 127, values which exceed at both ends the overall tessitura of the orchestra. However, for purely technical reasons when programming, we chose this division. If we multiply the highest value by two, the ending result will give us an upper limit of 254 for P1, maximum value which allows us to work with quarter tones.

Before carrying out any transfer of material from P1 to P2 we should select a determinate number of voices to which we will transfer everything that we have taken away from P1. We name them voices from a classical point of view, but they could be considered instruments with a determinate number of polyphony still controlled at this stage. In this way the distribution of that which is transferable would be different.

The selection of voices-instruments determines the distribution of what is transferred from P1 to P2. We always work with much more horizontal space (time) and a larger amount of voices than needed for the musical piece, so P2 behaves as if it were an electronic blackboard where we can store all the information that we may wish to use in the future.