Re: My eye sensitivity to blue-violet higher than normal


Harvey White
 

the shorter the wavelength of the light, the better focus you can get.  One reason why IR images are fuzzy (the other may be a compromise between different focus settings).  Since different colors focus at different distances in a lens, you need to have a camera lens designed for this.  Not at all sure that the human eye takes that into account at all.

Spot size is one reason that the DVD (blue-ray) blue light holds more data than a CD (IR light).

Xrays are used in lithography for most complicated ICs, not visible light, IIRC.

Harvey

On 5/23/2021 11:15 PM, Mark Vincent wrote:
It seems I really started something with my post. Thanks to those that have already replied. Any more would be welcome. I have known of my ability to see the higher frequency colours since I was a kid. I do not have any vision problems. All I know is the better ability to see blue to violet better than anyone I have met. Doctors I have told this to do not know exactly why I see better with these colours. It has to be a DNA feature that is determined in the womb. Other light colours do not bother me. Saying I may be a mutant by Mr. Carsten could be right on. A mutation in the DNA is possible if not likely.

Flicker does annoy me. NOVA had a show years ago titled "Can buildings make you sick". I bought a VHS tape of this after it aired to show people I am not the only one. One segment in that show verified that headaches and eye strain will occur to everyone in varying degrees. They used the typical 60 c/s fluorescent light source and a tungsten light on volunteers. The ones said it was easier to read and see under the latter for any length of time. Electronic ballasts operate so fast, the phosphour in the tube cannot fully decay in its glow like a standard transformer ballast. Now cheap LED lighting uses a half-wave supply. Better is filtered dc. Slowing a trace using any P number will annoy anyone. The slower sweep is needed at times, e.g. 20ms/div. I understand the mesh makes traces thicker no matter what P is on the inside.

For colour rendition, white is best. Read a resistor colour band under some light colours and the bands will look different.

It was found that sound on film had better fidelity when a blue to UV light was used on the soundtrack. The higher frequency of the light the higher audio frequencies be put in without the attenuation. Notice a shadow is sharper as the light source frequency increases. IC lithography uses UV.

I only use the scale illumination when needed. I keep it at minimum otherwise. The graticule is seen easily unless the ambient light level is too low. An EMI shield with a blue trace is no problem for me. Trace/readout intensity is kept as low as possible to see. The 7104 is barely visible until the trace is needed to be seen then brought up enough to see while keeping the yellow LED off then intensity back down. This is when I use that model. The crt in this is good, not weak by any means. Protect the MCP.

Mr. Gentry makes me wish convergence was still done. I miss NTSC and delta guns. Here is something for TV history people, Electronicam.

I have noticed the 2000 series never had Opt. 78.

Blue eyed people have less melanin. The mention of the WW2 navy using UV is interesting.

Thanks again for the replies. Anyone else is welcome. I have already learned things.

Mark




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