Best Day time colors for LEDs ??

Hi to all. My first post here.
I tried a search on this topic but thought I would ask the group here.

If you were looking for a signaling light for day time use what would be the best colors to use.
In other words. Do some color leds travel farther than others. Example if I ran an RC boat way out into a mile long lake what Color LEDS would be seen the farthest(daytime). I was thinking blue?? Mostly because this is what police use.

So in short . What are the best day time colors ?????

Thanks.......Flap...

Our daytime visual sensitivity peaks in the green.

I was always under the impression that safety orange is the most visible colour in the day, and yellow at night.

No sure if this applies to signally light, though stands to reason it would.


Regards,
Damien Siviero
http://damiensiviero.com

You also need to consider how many Lumens LEDs of different colours produce - here are figures of Maximum Lumens for CREE XP-E at 350mA

122 Cool White
31 Blue
100 Green
62 Amber
74 RedOrange
57 Red


Since this is battery powered, you should really compare on equal-power rather than equal-current. Below are the power levels for 0.35 amp.

3.2x.35=1.12 Cool White
3.2x.35=1.12 Blue
3.4x.35=1.19 Green
2.1x.35=0.74 Amber
2.1x.35=0.74 RedOrange
2.1x.35=0.74 Red


So in terms of Lumens per watt
109 Cool White
28 Blue
84 Green
84 Amber
100 RedOrange
73 Red

So Cool White produces most visible light per watt for this LED type - but RedOrange isn't far behind, thanks to LED efficiency at this colour.

You also need to consider contrast - e.g. if there will be green vegetation behind the light, a red light of the same luminous flux will be more visible than a green light.

RedOrange will be a lot more noticeable than White - except at Sunset !!!

Forget Blue.

The best way to make a light noticeable is flashing - even very short flashes can provide high visibility using minimal power.