## About display monitor settings and targets

Setting monitor controls and target behaviour for monitor calibration boils down to two things:
What is the equipment capable of without introducing side effects ?
What are you trying to do ?
You can make adjustments to a display using it's controls and/or the video card LUTs. Generally the former are more powerful and have less side effects. There can be exceptions though, for instance LCD's have no native contrast control capability, only brightness, so contrast is usually faked by manipulating the lookup curves, which can introduce side effects. The same applies to white point control on an LCD (unless it has R/G/B LED back lighting). So generally LCD displays are much less flexible than CRT displays in targeting some non-native colorspace without introducing side effects, so it is generally best to set all the LCD controls except back lighting brightness to their default settings.
Brightness depends on what you are trying to do. If you are trying to do soft proofing for instance, you will have some brightness level in mind dictated by the hard proofing booth you are comparing to, or the ambient brightens level. For good color judgement and low fatigue it's desirable that the display brightness roughly match that of the ambient lighting.
In terms of what you are trying to do, it comes down to what colorspace you want the display to be, and how far from native for that display it is. A CRT can be reasonably flexible in the behaviour it can be given without side effects, an LCD less so. If you want to minimize artefacts on an LCD you want to set the contrast and white points to their native values (ie. where the monitor is not manipulating the digital signal levels). It may not be easy to figure out what this is. In this scenario you would probably only want calibration to set the transfer characteristic and neutral axis, and leave the white point native.
For typical MSWindows/Linux this would probably be the typical CRT transfer ("gamma") curve, or a gamma of about 2.4. For OS X it would probably
be a gamma of 1.8 for versions 10.5 or earlier, or 2.4 for 10.6 or latter ("Snow Leopard").
The nominal white point of a display is D65 (set by Television standards), and an LCD's native white point is somewhere near there, but this is dictated by their backlight color. The CRT's will give maximum brightness with a much higher white point (9000K or so), but this can be reduced with fewer side effects (just reduced brightness) using typical CRT controls.
If you have specific requirements (trying to do soft proofing) then you may want to target a specific white point and brightness, and be prepared to compromise other aspects of the display to achieve this. By all means use the controls to move the display in the direction you want to go, and then use the calibration curves to get there. If you are moving far from native (especially on an LCD) you may find the side effects unacceptable though.