When the hdr image created by rpict is displayed on the display, the luminance is low

Hello community.

I created an image with a uniform luminance of 1000cd/m^2 using rpict, and displayed it on the display using photoshop as well.
I measured the luminance of the image with a Konica Minolta CS-100A spot luminance meter and found that it was only about 300cd/m^2.
The display is compatible with hdr images and is capable of outputting 1000cd/m^2.

Is there any way to display the luminance of the image created by rpict correctly?
(I have already verified that it is not a problem with the display and photoshop.)

Photoshop is not designed to understand calibration data from HDR images, so you cannot expect it to display calibrated output. Also, even HDR displays are generally not able to show an entire image field at maximum luminance. Their power supplies cannot handle it, so limit the output for large fields.