Monitors work with an additive color palette while an inkjet printer works with a subtractive one. If all colors at the highest level of saturation are arranged at one point on your screen the resulting color is white. The same scenario with your printer results in black.
Another very important difference is that your monitor is a light source where the luminance can be changed. A print reflects the ambient or direct light it is illuminated with. This means that your monitor may not accurately represent your image file. If your monitor is too bright, your print will appear too dark. If you are working on a monitor that is too bright, the exposure of your image file is artificially increased. If it appears too bright to your eye, you darken the file. The result is a print that is too dark. Your monitor needs to represent your image file faithfully.
There is a proper setting for your monitor’s brightness. The suggested luminance (a measurement of brightness) is around 120cd/m2 (candela per square meter). To work on a monitor with this luminance, you should be working in an environment that is dimly lit. The general rule is your monitor is the brightest light source.
To help find the proper level of room light, turn on a feature called Room Light in Spyder5PRO or Spyder5ELITE. Room Light will use the ambient light sensor on your Spyder to measure the lighting in your room. Adjust the light in your room until the Spyder software suggests that 120cd/m2 is the proper luminance for your monitor. Your room light level should dim but still allow you to read a short article comfortably.
Continue into the calibration and you will be asked to adjust the luminance of your monitor. The luminance setting is normally the brightness setting in your monitors menu, sometimes it is labeled as backlight. Use the setting that controls the overall brightness of your display.
Now with a calibrated monitor set to a luminance of 120 cd/m2, you should have better agreement between your monitor and your prints.