Forcing brightness level at startup or logon

[CHiLL]

We've got a situation where students are using Windows' brightness adjustment to lower the screen brightness to it's lowest where the screen is almost unreadable. The next time the tablet is used, it is extremely difficult to read what's on the screen due to how dark it is. There is no hardware or keyboard shortcut for this, so they are relying on Windows' brightness adjustment setting. Now, I don't want to disable this complete for accessibility reasons and whatnot...but I'd like to get the tablet to boot or log on with a certain brightness level each time it is used. That way the brightness adjustment is not permanent unless adjusted manually.

 

I have found this GPO:

Computer Configuration > Policies > Administrative Templates > System > Power Settings > Video and Display Settings > Specify the display dim brightness

 

I can set this, though I don't know if this will just be a one off setting or whether it will re-apply at every boot.

 

Anybody have any ideas?

[CHiLL]

I have found this script on the Internet and set it as a startup script:

 

REM Set Display Brightness Level
POWERCFG /SETDCVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 100
POWERCFG /SETACVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 100

REM Set 'Dimmed' Display Brightness Level
POWERCFG /SETDCVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 f1fbfde2-a960-4165-9f88-50667911ce96 100
POWERCFG /SETACVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 f1fbfde2-a960-4165-9f88-50667911ce96 100

REM Set Power Scheme As Active
POWERCFG /S 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c

Note: This script works specifically for my environment. To get it work in yours, use the following steps:

1) Log onto a machine with the active power plan in place

2) Open a command line and use 'powercfg /q' to get a report of your active power plans

3) The first entry will be your active power plan - copy the GUID and replace the first GUID in the above script with it

4) Scroll through the list until you see a subgroup named '(Display)' - copy the GUID and replace the second GUID in the above script with it

5) Scroll through the list until you see a subgroup named '(Display brightness)' - copy the GUID and replace the third GUID in the above script with it

6) Replace the last line GUID with your active power plan GUID from step 3).

 

It appears to work - however there's a massive delay in when it is applied. I have timed over a 5 minute delay from when the script is manually ran and when the screen brightness changes.

 

One other problem is that it is only being applied once. If after it has been applied the brightness is manually adjusted to the lowest setting and the machine is rebooted - it will remain dull until manually set by the user.

 

I have also tried using Computer Configuration > Preferences > Control Panel Settings > Scheduled Tasks > Immediate Task (At Least Windows 7) and having the script located in SYSVOL...but I can't get it working and it also appears to only be processed once.

[Guest obsidianpillar]

I have found this script on the Internet and set it as a startup script:

 

REM Set Display Brightness Level
POWERCFG /SETDCVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 100
POWERCFG /SETACVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 100

REM Set 'Dimmed' Display Brightness Level
POWERCFG /SETDCVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 f1fbfde2-a960-4165-9f88-50667911ce96 100
POWERCFG /SETACVALUEINDEX 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 f1fbfde2-a960-4165-9f88-50667911ce96 100

REM Set Power Scheme As Active
POWERCFG /S 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c

Note: This script works specifically for my environment. To get it work in yours, use the following steps:

1) Log onto a machine with the active power plan in place

2) Open a command line and use 'powercfg /q' to get a report of your active power plans

3) The first entry will be your active power plan - copy the GUID and replace the first GUID in the above script with it

4) Scroll through the list until you see a subgroup named '(Display)' - copy the GUID and replace the second GUID in the above script with it

5) Scroll through the list until you see a subgroup named '(Display brightness)' - copy the GUID and replace the third GUID in the above script with it

6) Replace the last line GUID with your active power plan GUID from step 3).

 

It appears to work - however there's a massive delay in when it is applied. I have timed over a 5 minute delay from when the script is manually ran and when the screen brightness changes.

 

One other problem is that it is only being applied once. If after it has been applied the brightness is manually adjusted to the lowest setting and the machine is rebooted - it will remain dull until manually set by the user.

 

I have also tried using Computer Configuration > Preferences > Control Panel Settings > Scheduled Tasks > Immediate Task (At Least Windows 7) and having the script located in SYSVOL...but I can't get it working and it also appears to only be processed once.

You could do an "IF EXIST.... GOTO :wherever" and then force it to process again? That's the way I've "forced" stuff in the past.

 

Where about's in Brum are you from? I'm from Kiddy, so only a stone's through away!

 

Tom

[CHiLL]

You could do an "IF EXIST.... GOTO :wherever" and then force it to process again? That's the way I've "forced" stuff in the past.

 

Where about's in Brum are you from? I'm from Kiddy, so only a stone's through away!

 

Tom

That's a good idea, cheers. I'll give that a go.

 

Originally I'm from Merseyside, though I'm living in Selly Oak area at the moment. Been down to Kidderminster a couple of times - nice area to drive around.

Edited September 2, 2021 by ZeroHour

[Guest obsidianpillar]

That's a good idea, cheers. I'll give that a go.

 

Originally I'm from Merseyside, though I'm living in Selly Oak area at the moment. Been down to Kidderminster a couple of times - nice area to drive around.

 

Hi, any luck with trying what I suggested? It's the first thing that came into my mind, so unsure as to if it'll work or not!

 

Selly Oak's nice, I was around there not too long ago in February and due to return soon to see the demolition of the old hospital. How long have you been living there? Kidderminster's fairly nice to drive around (in some areas), however like any town you'd be advised to avoid certain areas!

 

Tom

[CHiLL]

Hi, any luck with trying what I suggested? It's the first thing that came into my mind, so unsure as to if it'll work or not!

 

Selly Oak's nice, I was around there not too long ago in February and due to return soon to see the demolition of the old hospital. How long have you been living there? Kidderminster's fairly nice to drive around (in some areas), however like any town you'd be advised to avoid certain areas!

 

Tom

This got a little derailed whilst I was battling a domain time synchronisation issue. Now that is sorted, I'll give it a go.

 

Been here for around 5 years, though Selly Oak is full of students, I think the stats were that around 50% of the population are university students, mainly for the UoB. I'm hopefully moving to Harborne soon, which is a nice area. Since the weather it nice, I might take a drive over to the Wyre Forest and have a nice day out.

Edited September 2, 2021 by ZeroHour

[CHiLL]

I've managed to get it sorted using Powershell and Group Policy Startup Scripts. This has only been tested on Windows 8.1 at this point. The commands I used:

$monitor = Get-WmiObject -ns root/wmi -class wmiMonitorBrightNessMethods
$monitor.WmiSetBrightness(100,100) #First number is the brightness percentage level for when the device is plugged in, second number is for when it is on battery

I used Group Policy with this setting: Computer Computer Configuration > Policies > Windows Settings > Scripts > Startup > Powershell Scripts

Add the script into the directory and in 'Script Parameters':

-ExecutionPolicy Bypass

It may take several seconds (around 10 on our small detachable Windows tablets) for the script to be processed.

 

Note:This only appears to work on certain device types with adjustable brightness displays for power saving, such as laptops and tablets.