All of the above factors assume that the mind perceives that there is something worthwhile to see. Any discontinuity in the edge of an object tends to limit the integration of that edge into the whole. This is the principle of camouflage where we find the image broken up in irregularly shaped lines. Such things as painted wing tips, striping, registration marks, while helpful when we are near aircraft, only tend to camouflage it once the object is more than 1000 feet (300 metres) away. Additionally our colour vision receptors in the eye are much less accurate the further the object is away. Yellow seems to be the most recognizable colour, but all others drop off quite quickly and we usually only accurately detect objects by their profile. This assumes we have not been applying the basic camouflage techniques when we“decorated” our aircraft. I also find it amusing that licenced aerodromes use a windsock with alternating bands, which effectively hides this wind indicator from pilots in the circuit! The net result of this is that if we are trying to recognize an aircraft by its profile at some distance, it will be less distinguishable if it is banded. On the other hand if we are trying to avoid a collision in a gaggle of gliders then such markings are helpful.
To compensate for these problems we can wear the appropriate eye wear that limits glare with the lightest possible tint. Blue light blocking sunglasses are becoming quite popular in this regard as they protect the eyes from harmful ultraviolet rays yet offer high transmission of light. The blue light wavelength receptors in the eye are not as effective as those for other colours, and tend to interfere with the perception of details. As such blue-blocking eyewear can have the added benefit of increasing definition of objects at a distance. Other combinations of tints achieve the same effect but may show colours more truly. There have been several excellent articles in the soaring publications “Soaring” and “Sailplane & Gliding” in recent years on this topic. Additionally we can train pilots in effective scanning techniques to cope with our limitations. These will be outlined later in the basic skills section.