How red should red be????

[Mav359]

Hello peeps

In order to save my night vision from my I-phone, i-pad, laptop and torch I have started to red filter them all.

I have bought red cellophane that the florists used, is great, easy work with and it's cheap. It is however quite thin, so multiple layers I hear you cry, again easy and it works great but .....

How thick or dark does a red filter need to be??? Is just to the point where my dark vision remains fine??? How do I know that will be good enough if I rock up to a field but it isn't good enough for everyone else....

Thoughts please

[Demonperformer]

As a rule of thumb, I would say make them as thick (dark) as you can and still be able to read the display. The less extraneous light (red or otherwise) around the better.

[brianb]

You need to completely exclude all light shorter in wavelength than 640 nm ... that's a fairly deep red filter, about equivalent to the Wratten #29. Even then keep the intensity as low as possible.

[Mav359]

cheers guys

[ollypenrice]

When imaging I am condemned to suffer the presence of a computer screen. When doing visual, all such nonsense is banned! Paper, dim red torch, no gadgets.

Olly