[argyllcms] Re: How can I tell if I'm using my profile? (and other questions)
Is there some resource I can use to estimate it? (e.g. I have the room illuminated by one 19 W fluorescent bulb, the room has certain dimensions, and there is one window..... Light level is of course different at noon than at midnight, but I might have a night profile and a day profile, I suppose.) What assumption about ambient light level is the default? (Or what assumption is built in if you don't add a correction?) 

There are no assumptions made if you don't specify and ambient level,
an ambient rendering adjustment simply isn't applied.
But if ambient light level truly matters then there must be some built in assumption about what it means to not apply this adjustment. Does this mean that the ambient level is assumed to be zero? Or the ambient level is assumed to be equal to the display brightness? (Those would appear to be the two possible assumptions.) 

It's actually the ratio of the ambient level to the brightness of
the display that counts, so you could use that as a guide, but
you would essentially be "tweaking by eye".

Graeme Gill.

Other related posts: