[Elecraft] Blue Displays and Visual Acuity

[Eric Fitzgerald]

 From the artistic side of color theory, I know both red and blue are  
low value colors - value being light/dark.

I suspect this is simply because of their proximity to the edges of  
the visual spectrum.



73 de Eric, KG6MZS


On Jun 17, 2009, at 12:34 PM, Ron D'Eau Claire wrote:

> Interesting experiment, Alan. I've not tried it but a little  
> research backs
> you up! One source (University of Illinois Dept. of Physics) says "  
> The
> blue-sensitive cones are the least numerous, and are also spread  
> out away
> from the fovea. This is one reason why it is harder to get a sharp  
> visual
> impression of something blue than something of other colors."
>
> I find the sort of white light I use for fine work (5800K color  
> temp) tiring
> over time and I've read that the blue end of the spectrum offers  
> better
> resolution due to the shorter wavelength. In any event 5800K lights  
> are
> "bluish" but contain elements of the whole color spectrum just like
> sunlight.
>
> For something other than "white light", you may be right that a  
> mixture of
> blue and yellow light (green) actually works better.
>
> There's also possibility a psychological effect about "blueish"  
> light (e.g.
> sunlight) that has nothing to do with the physiology of vision. We  
> humans
> are conditioned to be alert when bathed in "sunlight". Specialists  
> in sleep
> disorders often recommend shifting to redder and dimmer lights as  
> we move
> toward bedtime. They claim it greatly increases our ability to  
> drift off to
> sleep.
>
> I do know from personal experience that it's hard to see detail in red
> light, having sat in many aircraft cockpits with the red night  
> vision lights
> on straining to read a legend on a chart! Same is true for the  
> bridge of a
> ship rigged for night.
>
> Whatever the underlying causes, I do find blue light jarring, while  
> redder
> light is softer and more relaxing.
>
> I operate to relax. I was waiting for a hard-core contester or DX- 
> chaser to
> say he/she wants to be wide awake and "on edge", that's why he  
> likes the
> blue light. That would make good sense, but no one did - so far ;-)
>
> Never hesitate to challenge me. A forum like this isn't about  
> "being right".
> It's about open discussion and learning.
>
> Tnx!
>
> Ron AC7AC
>
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of  
> gard at btinternet.com
> Sent: Wednesday, June 17, 2009 11:55 AM
> To: Elecraft Mailman
> Subject: [Elecraft] Blue Displays and Visual Acuity
>
>
> Hi
>
> I'm really hesitant about challenging such an accepted authority as  
> AC7AC on
> any topic.  But I think he is incorrect when he says "blue light  
> provides
> the greatest visual acuity."
>
> A simple experiment (which I have seen performed) can confirm  
> this.  Project
> a graded black and white resolution pattern in white light.  Cover the
> projection lens successively with red, green and blue colour- 
> separation
> filters and see how many of the patterns the eye can resolve in  
> each case.
> You will be amazed at how few can be counted through the blue  
> filter when
> compared with the green or, to a lesser extent, the red.
>
> This characteristic of normal human vision is acknowledged in the  
> design of
> RGB television systems where less bandwidth is allocated to the blue
> signal.  If it's acuity you are looking for, green is your colour,  
> not blue!
>
> 73 de Alan G4LWA
>
>
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