SECRET COLOURFUL MESSAGES
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By using particular coloured filters it is possible to decode colourful secret messages or change the shape of a drawing. Children have fun when they are challenged to make their own secret messages to be deciphered by the classmates.
The
word PIACENZA (the
name of an Italian town) read through a red filter becomes "PC" and
read through a green filter becomes PACE (in Italian it means peace)
The
Italian phrase GIRO CON DANIELE CHE OGGI LAVORA DI PIU'!! read
through a red filter becomes "GIOCO DI COLORI!! (that
means" play of colours!!")
The flower with yellow petals of the picture, viewed through a red filter, appears like a black sun (only the central part, that appears green without filters, is visible).
How do coloured filters change the colour we see?
The colours of objects comes from their reflection and absorption of different parts of the spectrum. When a colour filter is interposed between the object and the observer’s eyes, most colours of the spectrum are absorbed by the filter; only the light having the colour of the filter bounce off it. For example, if we observe through a red filter a word written with different colours on white paper, we can’t distinguish the red letters, because also the background becomes red; the letters that don’t reflect the red light appear black and well visible.
