Coloured overlays.

Coloured overlays are sheets of coloured plastic film suitable for placing over a page of text when reading. There are several sets on the market. For example, a set is manufactured by i.O.O. Sales (NB Not 100 Sales), another by Cerium Visual Technologies and a third by Crossbow Education. Overlays with a small number of colours are insufficient. It is necessary to obtain overlays that sample a large number of colours systematically and efficiently, for example, as in the figure.


Diagram showing chromaticity of overlays

The effects of coloured overlays on reading fluency are reviewed elsewhere.

Teachers and others involved in the assessment of children using overlays may find additional instructions helpful. The beneficial effects of the overlays on reading fluency can be assessed using the Rate of Reading Test, also available from i.O.O. Sales and Cerium Visual Technologies.

The Intuitive Overlays have been shown to be of benefit to many primary school children. About 5% of children read >25% more quickly with an overlay. The overlays can be cut down to suit the size of the text.

Children who find overlays helpful usually go on to coloured lenses.  The colour of the overlay and the colour of the lenses are not the same.

The figure shows the spectral reflectances of the Intuitive Overlays, together with their chromaticities (inner ring of points) and the chromaticities of two overlays superimposed (outer ring of points). (The spokes connect the chromaticites of the single overlays with those of two identically coloured overlays superimposed, and the interstitial points show the chromaticites of two overlays having neighbouring chromaticity.)


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