The Ford Barn - View Single Post - Using Blue dot lens on stock tail light buckets

MikeK · 03-14-2017, 07:03 PM

Blue dots in red tail lenses date back to the early 30’s. They were standard on 31-33 Cadillac V12 &16’s and 32-34 Packard V12’s. Aftermarket use followed.

The intense visual response to the purplish apparent color is twofold:

1) The human eye has receptors for three primary colors and red tail lights stimulate only red receptors. Adding the blue spot causes response to two color band receptors and is perceived as brighter or more intense.

2) The human eye is not achromatic and cannot focus sharply at a distance to both red and blue in a dark environment, when the iris is full open and there is no ‘depth of field’ to make all colors focus at the same time, as in daylight. As a result, your brain frantically drives your eye muscles to search for focus. This causes heightened alarm in your unconscious perception.

03-14-2017, 07:03 PM	#16
MikeK Senior Member Join Date: May 2010 Location: Windy City Posts: 2,919	Re: Using Blue dot lens on stock tail light buckets Blue dots in red tail lenses date back to the early 30’s. They were standard on 31-33 Cadillac V12 &16’s and 32-34 Packard V12’s. Aftermarket use followed. The intense visual response to the purplish apparent color is twofold: 1) The human eye has receptors for three primary colors and red tail lights stimulate only red receptors. Adding the blue spot causes response to two color band receptors and is perceived as brighter or more intense. 2) The human eye is not achromatic and cannot focus sharply at a distance to both red and blue in a dark environment, when the iris is full open and there is no ‘depth of field’ to make all colors focus at the same time, as in daylight. As a result, your brain frantically drives your eye muscles to search for focus. This causes heightened alarm in your unconscious perception.