Well, it's morning somewhere. 😉 This will be lengthy, and not really even everything I could explain. But it hits the major points.
I'm going to assume you're using i1 Profiler, which I linked to above rather than whatever version of software the unit shipped with. Plug in the measurement unit first, then launch the app and click on the Advanced button at the right to get the menus to look like the left side of my screen shot. Most of yours will say DEMO. Towards the lower right, choose the monitor profiling device you have. There's only two choices. Either an i1 Pro spectrophotometer, or your i1 Display Pro colorimeter.
Click on Profiling at the top right to get to this next screen.
Click on the button for your display, which will center the work screen on the active display. If you have more than one monitor, they'll both have a button and the work screen will jump to that monitor so you know that's the one you're profiling.
The D under the white point settings stands for Daylight, which is quite a range depending on where you are, time of day, etc. The choice for D65 (6500K) is considered normal daylight white. Problem is, that's the way a measurement device sees the color of white. Our brains don't work that way. It automatically tries to neutralize color no matter what the light source is. An example is watching a video of someone in a store, and the camera has been gray balanced to the lighting inside. Then they walk out of the store to a cloudy day. If the camera isn't set to automatically balance the white point, the scene outside will turn very blue. When we do that, our brains make the adjustment back to neutral without any conscious effort on our part to try and rebalance color. So while a device may see sunlight as 6500K, our brains don't. That's partly why monitors set to 6500K look so unnaturally blue.
Walk into any professional print shop, and you'll find GTI (or other brands of) viewing booths all over the place. The color is set to 5000K, which produces about the most neutral color we perceive as gray. It's also the closest white point to the most commonly used papers in printing, which is publication stock for magazines, flyers and such. The 1.8 gamma used by the printing industry is also not a random choice. That's about how much ink you can put on most papers before it gets too wet and starts to ripple.
So personally, I would suggest using D50 for your white point, and is what I think everyone should be using. Set luminance no higher than 100. Anything higher is going to be way past what reflective light will give you off of a piece of paper. That's your goal. A screen that matches the output the printer is capable of. Or at least, as close of a proximity as possible between reflective paper, and a luminant source of color (your monitor). Also, most monitor manufacturers won't observe the warranty of a monitor that has been continuously used above 120 lumens, as you will wear it out way ahead of it's life expectancy.
You must turn off any ambient lighting on the Macs. That is, don't allow them to brighten or darken on their own according to the surrounding lighting. When you profile a monitor, you are actually doing two things. First is calibration. That consists of setting the white point, black point, gain, and luminance. Once you've calibrated the monitor, then you profile it by reading the color patches.
Say you've finished creating your profile. Since the color of the monitor will change with any alteration of the calibration steps, the profile you created is invalidated (no longer accurate). You can test this for yourself. Put any colorful image on the screen. Increase the brightness. Notice that it doesn't just get brighter, but color gets more saturated. If you reduce the brightness, color gets less saturated. So you are changing not just the brightness, but also the color of the screen, and the profile is no longer a mathematical representation of the color it was displaying at the time it was measured.
Leave contrast ratio at Native. That means use the darkest black the monitor can produce. Next screen:
Personally, I still use Version 2 ICC profiles, but you can leave it on Version 4 if you wish. Minor history note. Version 3 was found to have such major flaws in it, the ICC consortium decided to skip its release and bypassed it to the next official standard as version 4. Set the gamma to what you would prefer. For me, it's 1.8 since I mostly do work for the printing industry. 2.2 is considered what the human eye can differentiate for shadow detail. 2.0 is about the darkest color you can print on expensive papers. You'll never get 2.2 on paper without soaking it.
On the next screen, pick a patch set. The smallest serves most purposes. Pick a larger one if you don't mind sitting and watching for a while. Under Display Hardware Setup, you could try Automatic Display Control (ADC) if you want. The software will then take over setting the brightness and other calibration choices on its own. You'll know your computer doesn't support it if the screen goes black. Then you have to press Command+Q to get out of the profiling software and start over. The screen should come back to normal. If does go black, then you'll have to remember to turn that check box off. Be sure also then to turn the other check box on to set things manually. Otherwise, you won't get a chance to change the brightness at all.
Next screen. Click the Calibrate button to zero out the device, then Start Measurement to read the patches. You will be prompted to place the device so it hangs across the screen. Preferably, in the center. You'll see this box at the upper left.
Your Mac will not have gain, black point or separate RGB controls, so if you have ADC off, have only the Brightness box checked. You will be prompted to adjust the brightness until a gauge on the screen is at the center. When you hit that, it will be at your target luminance setting. Click Next. The software will now start to read the profiling color patches.
When that step is done, i1 Profiler will come back to the work screen. You'll see all of the patches color now split diagonally. Click Next. Give the profile a name that makes sense to you if you're not thrilled with the default name it uses. I give mine a monitor or device name and the date. So it would be something like iMac 9-26-14.icc. Click Create and save profile. Once finished, it will automatically set the System Preferences to use the newly created profile for the monitor.
Now, depending on how accurate your printer profiles are, you should get a much closer color match of your prints to the monitor.
