Hi Allen,
I think you may be getting your units crossed here.
The numbers 20 and 80 refer to the luminance (brightness) setting of the monitor and have units of Candles/sq meter (CD/M2).
Certainly, lowering the brightness of your monitor can help in adjusting images on the monitor so that prints no longer appear dark relative to the monitor. Some are known to adjust the brightness to the prints and calibrate to make a profile after doing that.
Your dE figures are not really relevant to print brightness; they give a measure of the accuracy of the monitor in reproducing the calibration patch colours; it indicates an out-of-gamut amount . Your figures are very good by the way, anything below 1 is good according to what I was told by Gretag McBeth (now XRite) and up to 3 is satisfactory. What monitor do you have?
BTW. my comments have assumed you use a printer profile too.
Also, I have found that on some papers, my prints are a little dark in shadow areas (monitor at 120 CD/M) so I use a little Fill with a Qimage Print Filter.
Terry

I've been using ColorEyes Display Pro software for over a year and the validation report you posted is excellent.  I question the Luminance value of 80cd/m2 unless you are using the highest quality of LCD monitors with high bit internal color processing.  I use a modest Dell 2209WA, which is a budget level IPS paneled monitor and I calibrate to 110cd/m2.  If your monitor is not capable of reaching 80cd/m2 by using the OSD Brightness control alone, the CEDP software will go directly to your video card and compress the RGB color tones there.

Hello Chas,

Does it mean you are happy with the monitor when use it for pictures? Based on your opinion I am thinking about purchasing it for pictures and text reading. What about calibration? I have EyeOne 2.

Regards,
Roma

Hello Chas,

Thank you for your advice. Today I have learned that NEC is also manufacturing a wide colour gamut LCD2690WUXi2. See what I have found on the NEC web site:

Sporting a wide color gamut panel, the 26" NEC refurbished MultiSync LCD2690WUXi2 equips you with all of the features and benefits ideal for high-end graphics applications.
97.8% coverage of the Adobe RGB color space
With NEC's exclusive X-LightTM Pro backlight/sensor design, brightness and color settings can be held constant over the useful life of the display
ColorCompTM technology compensates for slight variations in luminance and color uniformity, providing even color across the screen
Superior screen performance (1000:1 contrast ratio, 1920 x 1200 native resolution, 320cd/m2 brightness)
Supports internal programmable 12-bit lookup tables (LUTs) for calibration
Ambient light sensor and automatic backlight adjustment allows for use in any lighting condition

Regards,
Roma