As you can see I tried to work out how they worked by creating a rainbow of colours in pencils and then seeing if the lenses worked with any of the colours. In the end I found that the most effective colour to use was the pink that I had use in some of my earlier tests. This was because it seemed more transparent when applied to the acetate. However, maintaining an even colour over the entirety of the sheet so I have had to change my approach. Instead of having full coloured sheets that are placed over the designs I will make small windows that are held up to the eye this way the colour can be more even and less distortion will occur.