Why you should use a black skirted mask

It is often asked in dive shops as to why someone would want a dark skirted mask.  The answer can vary between "it's just to look techie" to "you don't want one, it makes people feel claustrophobic." Both answers contain a certain amount of truth but are not completely accurate. Let's start with a physiology lesson about your eyes. The eyes contain two types of receptors, rods and cones. Both do slightly different jobs.
Rods Cones
Good in low light Excellent colour perception
Around the side of the retina Centre of the retina
Very sensitive to movement Render much finer detail
http://en.wikipedia.org/wiki/Cone_cell http://en.wikipedia.org/wiki/Rod_cell
  The practical application of these are that during the day the cones work hard giving us high definition colour vision. At night the rods are more useful but offer less detail and no real colour (everything is black/greenish). The rods are excellent at spotting movement, remember the saying "I caught sight of ... out of the corner of my eye." You did, but in fact (to be accurate) your rods spotted the movement. In basic military training soldiers are taught never to look directly at perceived movement rather look out the side of their eyes. It goes back to primitive times when ambush by predictors was most likely at dawn/dusk, we evolved rods to ensure our survival at low light times. That's a lot of talk about rods, but surely we want to know more about the cones. We like colour and detail. When you wear a dark skirted mask you are restricting your peripheral vision meaning more of your brains optical processing power is concentrated into the cones. Your brain can only process so much optical data at a time (I am not sure if it is true but someone once told me that if you hold a 5p piece at arms length and look at it that is about all your brain can actually concentrate on - try it, seems about right, yes you can see a lot more around it but actually concentrating on). The use of black skirted masks has been very popular with underwater camera users for many years due to the increased colour perception these masks can help achieve. Do you use a dark silicone skirt mask? How do you find it? Do you notice improved colour perception?

1 comment

  • I prefer black-skirted masks mainly because they provide better contrast, especially in shallower water where a transparent skirt lets in a lot of spurious light and creates internal reflections on the glass.

    Caver

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