On Wed, Dec 25, 2019 at 11:15:45AM +1100, Graeme Gill <graeme@xxxxxxxxxxxxx>
wrote:
Vallo Kallaste wrote:
Hi,
I noticed that dispcal sRGB TRC target elevates black brightness, it isn't
native anymore althought it says so:
/--/
Target black brightness = native brightness
Target gamma = sRGB curve
this depends on how accurate your instrument is for low level
measurements. dispcal uses the device values that
correspond to the minimum measured value. This is to allow
for devices that do not actually output their minimum
level with device 0,0,0, and for devices that have a poor
response from zero (i.e. they have a very flat response
where there is little change in output for the initial
device values. On inversion this can make for a very abrupt
transition from black to not quite black, so it's better
to choose a black that is closer to the point where the
device starts to behave proportionally. You may loose a little
on absolute black level, but you gain in shadow detail.)
[ The whole point of calibration & profiling is NOT to make any
assumptions about how the display behaves! ]
If somehow you _know_ that your display is at its minimum
at device 0,0,0 and has a good proportional response from zero,
then you can use the -k0 flag.
