The difference between 350 and 400 lux?

[marko333]

Hi list,

Can a human eye distinguish between 350 and 400 lux lighting levels?

I can understand that between 0 and 50 lux, there is a big difference between illumination, but as you go higher in lighting level over an area, will a human eye notice that some areas are at 400 lux and other areas are at 500lux?

Is there a general rule to this, or some emperical data?

Regards,

Marko

 

[IRstuff]

Depending on how far apart they are. If they're adjacent, then definitely yes. There are various contrast vs illumination data floating around. The Weber curve is one form.

The eye has better than 2% absolute contrast resolution, over a fairly large range of backgrounds.

TTFN

 

[JMEV]

The human eye typically requires a 3:1 difference to see a good "contrast" between differing luminance levels. However, if you are illuminating an area to 350 lux for a task that requires 400 lux. You may hinder productivity or accuracy.

The human eye is very sensitive and adaptable to huge variances in light levels. But, something is always easier to see with proper (usually higher) illumination levels and good uniformity. Even if it is only 15%.