that is quite a bit of info to chew over for a while
THANK YOU VERY MUCH!
If your prints don't match your monitor, you need a custom ICC profile for the monitor! The only good way to get one is to buy a calibration/profiling kit from DataColor or X-Rite, install the software, plug in the colorimeter, and run the software. Kits start at about $100 and go up to $500 or more. A decent calibration kit costs $150 to $200. If you print large prints, it will save you a fortune in ink and paper.
Here are some aims to set in the software, based upon my experience running the color correction department of a large photo lab:
Monitor brightness (white point) should be turned down to between 80 and 120 cd/m^2 (candelas per square meter). If your cal kit senses room brightness, it will recommend a level for you.
Monitor black point should be around 0.5 cd/m^2
Monitor gamma should be 2.2, if your software allows setting it.
Color temperature should be around 5800 to 6500K, depending on the brightness. Most software will tell you. Some software will set it for you.
The profiling kit calibrates the monitor via those initial settings, but mostly with a profile that creates 3D lookup tables loaded into your video card. The result is that you can adjust images in software, and print them to a calibrated and profiled printer, with nearly what-you-see-is-what-you-get results.
Don't overlook print viewing conditions! You need a print viewing box or small area behind the monitor surface that is matched in brightness to the monitor (visual evaluation is good enough for that). It should contain a 5000K, CRI 91+ light source. Room light in the area should be very subdued. Bouncing a small 5000K light source off the ceiling for diffuse, indirect task lighting is recommended. If you're really serious, paint everything a neutral medium gray, and make your computer desktop a medium gray as well (no brightly colored objects or lights should be in your field of view when evaluating colors.
Allow your monitor to warm up for 20 to 30 minutes, and your eyes to dark adapt to the room, before evaluating color.
And for goodness' sake, if you have a Mac, be sure the Night Shift mode is turned off! Turn off the Automatically Adjust Brightness feature before you ever calibrate, and leave it off permanently, to protect the integrity of your calibration and profile. RE-calibrate and profile at least monthly, or any time you suspect someone has "adjusted" your monitor for you.
Finally, learn how to use color profiles (ICC color management) correctly. A discussion of that is beyond this post, except to say that if you put images on the Internet, they should be JPEGs in sRGB. If you send files to a traditional professional wet process photo lab (Bay Photo, Full Color, American Color Lab, Millers, MPix, H&H, etc.), they should be JPEGs in sRGB UNLESS the lab specifically instructs otherwise.
Wider gamut profiles such as Adobe RGB and ProPhoto RGB have special applications in commercial printing, and may be useful if you have a "closed loop" printer setup at home. Avoid them for anything else.