Hi everybody,

I am working on a project which tries to control illumination by
controling the electrical power consumed by an electrical lamp (a form
of dimmer). In a part of this project I need to discuss the relation
between the change in the illumination with what the visual system
senses. I know that there is a logarithmic relation in sound where dB
is used to express the way our auditory system operate and feel but
does a similar relation applies to visual system or is there any
relation or curve relating the change in the illumination to the effect
it has on the visual feeling. Can anybody introduce a web source or
book on this?
Many thanks for your help.

Khashayar