Given the huge variation in (mis)calibrated settings on top of the huge variation of displays themselves, you'd probably be fine running f.lux. In fact, I would think you would want a more flexible tool so you can actually test what different users might be seeing given different display configurations.

I agree for the most part, however when I'm at the design phase I'm generally working from required brand palettes or using swatches I've defined so I know the colors are good.

Maybe I'm Doing It Wrong™, but I design all the time with F.lux in this manner and don't have any problems.

False. Apple computers use ColorSync, the whole point of which is to line up the perceived color on disparate devices in disparate locations:

http://en.wikipedia.org/wiki/ColorSync

In comparison, the color handling/prioritization in Windows and Linux is crap.

So, I am wrong if your entire audience is using Apple computers?

I will take those odds.

Not very relevant - a lot more people use Windows and Linux than Mac OS.

There are color management solutions for Windows and Linux as well -- the important part is that you calibrate your display (or other output device) to create an ICC profile, and that there's a way to install the ICC profile. (Example: http://www.lightroomforums.net/showthread.php?14070)

It's true that ICC profiles don't get you much if everyone involved doesn't have a calibrated display. And many users don't. That said, it's still valuable as a baseline and when working with other designers.

The discussion is around web design / development - a field with an extremely high number of people running OSX (I'd say that the majority run OSX, but I don't have any statistics to back that up, just observation).

No, the discussion is around web design clients, the majority of whom in my experience run IE6 on Windows XP at 800x600 with the brightness turned up to 11.

Working on calibrated equipment is about having a neutral, uniform reference so that you can actually see what you're doing without having to second guess yourself. You can draw an analogy to reference monitors for sound mixing. Monitors have two properties: they reveal detail in the sound and they have a flat frequency response. The former is obviously important, and it's why as a designer you should have a nice monitor. The latter is important so that when you work in different locations, you don't have to recalibrate your expectations. There may also be non-linear perceptual illusions associated with certain aspects of the signal being attenuated or boosted, which would be another reason to have a calibrated/flat reference, but I'm not certain if this would be relevant at the scale we're talking about (between calibrated and the whole space of non-calibrated color profiles).

I don't get out much, but I only know 1 (out of > 15) web-developers that use Windows...

> more people use Windows and Linux than Mac OS

Web developers are a small segment of all people who use computers.

You've taken this too far. My point was that while it's possible for me to modify my experience to my liking, I keep as many "defaults" as possible so as to have as close to the same experience as my clients and their customers.

So turn it off while you are working.

I agree for design. But for development, I feel like I can get the feel of what I'm doing even without full luminance.

f.lux has a suspend for an hour function for when you're doing color sensitive work. You can also turn it off entirely if you'd like. I don't do photo editing or anything majorly graphical with it on.

Agreed on both counts. I got tired of hitting "suspend for an hour" every single goddamn hour, so I had to tell it I live somewhere in the middle of nowhere. that aligns more with my ideal sleep habits.