Fading colors — degradation of paper over time
I recently decided to get rid of some old origami models which had faded beyond looking nice. On these Sonobe units retrieved from some modular assembly one can well see the deterioration of colors in inexpensive paper over time. The parts with vivid colors were hidden below additional layers of paper and so were protected from most sunlight. The bleak parts are those which were exposed to light (it’s probably ultraviolet radiation which is responsible for most of the decay).
Since I sign and date most of my works, I was able to check when the model was folded — November 23rd, 2002 — which means this paper was aged over 12 years. This is paper from a 9×9 cm note cube, most probably from Herlitz.