I have a Dell U2415 monitor and an Inspiron with Intel HD Graphics 630. I have several questions.
1. The monitor was factory-tested to conform to an sRGB profile, with a 6500K color temperatur. The supplied calibration shows delta E of <1. Unfortunately, except for color temperature, the calibration does not state what settings and presets to use. Was that the Standard preset, the Paper preset, or something else? Supposedly the sRGB standard viewing conditions are 80 cd/m^2, which .
2. In an initial attempt to check the calibration with an old, borrowed instrument, I used the Windows 10 built-in adjustments (cddw.exe) to adjust the gamma setting. I don't know where the setting is stored (on the display adapter??), or how to restore the default. I usually use the monitor on Linux. Did adjusting the gamma invalidate the monitor calibration on my Linux system?
3. I will be recalibrating with a new instrument, and I need to know what kind of backlight the monitor has. Is it white LED or RGB LED?
I see that this case is already being worked via Private Message by a DELL-Cares agent. Just adding some thoughts.
* This U2415 shipped from Dell on January 30, 2017. Warranty goes to April 30, 2020. You have to fill out the Service Tag number Ownership Transfer form
* LG AH-IPS (LM240WUA-SSA1) panel
* The Standard Preset was used to calibrate at the manufacturer factory. Those baseline settings then cascade to all other Preset Modes
* The online U2415 User's Guide only states, "Backlight = LED edgelight system". It does not mention white LED or RGB LED
* In the Menu, Color- Input Color Format should be RGB
* The U2415 was never tested by Dell in Linux. So we cannot speak to this. In addition to doing the Menu- Others- Factory Reset, in Windows, you could download and run the free softMCCS to restore the monitor to factory defaults