High Sierra - Screen Brightness

[spock999]

I updated to High Sierra from El Capitan at the start of the month. Basically all OK but I have noticed problems with screen brightness changing.

Under El Capitan, I calibrated my screen using SpyderPro4 and it was very consistent. Now it has reverted to full brightness everytime I startup. I drop the brightness using the F1 key and when I come back after a while with the screen timing out and sometimes it has changed. Other times it remains as set. It can go back to full brightness or it can drop right down in brightness. I haven't tried to recalibrate as I want it to be consistent first.

Grateful for any suggestions as to what to do.

Thanks

 

[Raz0rEdge]

You don't say what Mac you have, but MBP's do have the ability to change brightness based on ambient light. So the "Automatically adjust brightness" setting on Displays will vary the brightness based on the ambient light sensor.

 

[spock999]

Sorry! The problem is on my late 2015 iMac (27 inch 5K retina). It was never an issue under El Capitan it stayed consistently at a level that was comfortable. Now it varies substantially and is a real irritation. I would expect an ambient light sensor to be set up so that the user had a fairly consistent viewing experience. Not the case here.

It looks to me like the installation changed something but I am not sure what or how to sort it out. Interestingly my MBP was upgraded a few days before the iMac and there isn't any issue with brightness at all. That had also been calibrated.

 

[Raz0rEdge]

Thank you for the extra info. I don't believe the iMac has an ambient light sensor, so it shouldn't be changing the brightness on you. On my 2009 iMac I don't believe I've seen the brightness change through the updates. The setting seems to stick (I'm assuming since it doesn't seem to vary from time to time) where I set it.

You might want to reset the SMC/PRAM just to see if it does have any effect or not.

 

[IWT]

In posting to this thread, I have to emphasise that I am still running macOS Sierra; but System Preferences > Displays, brings up this window which does allow for "Automatically adjust brightness" to be turned on or off.

And, of course, there is the Night Shift Mode which can be similarly activated or otherwise.



Ian

 

[Raz0rEdge]

Ian brings up a good point. I have the pre-Retina iMacs, so you might have different/better settings related to that.

 

[spock999]

That's fine - thank you everyone. I have taken note of the various suggestions but am taking them one at a time to see which one is effective.

 

[chscag]

The retina iMacs do have an ambient light sensor and will adjust brightness accordingly. I've mentioned this before.... on my 2017 iMac 27" 5K, even with the "adjust brightness automatically" on it will only adjust it down so much. Which for me is still too bright. I have the automatic adjust turned off and use the F1, F2 keys instead. The retina screens used by Apple on its 27" displays are very bright and do not adjust well. Another annoyance is the Sunrise to Sunset settings which do not work very well on these new displays. My older iMac which I gave to my Son (2013 27" iMac non retina) was very easy to adjust and the Sunrise to Sunset setting worked very well.

 

[spock999]

Following the various suggestions, I have reset the PRAM which did seem to stabalise things. I have also turned off automatic brightness adjustment. Together, they have left me with a consistent brightness so all is OK now.

 

[Raz0rEdge]

Excellent!

 

[ferrarr]

Did you check to see if you are still using your display calibrated profile?