Software to sync multi-monitor brightness with an offset?

[Makosuke]

I just got a ViewSonic VX1655-4K-OLED portable monitor to go with my MBP. Have been using an HD, non-OLED one for a while for work, and finally decided it wasn't worth putting up with the grainy resolution, comparatively poor color, and fixed brightness.

Positives: The 4K OLED version is really expensive, but mostly lives up to all the glowing reviews--sharp, nice color, and HDR.

Good news: In HDR mode, you can adjust the bribhtness via macOS so I don't have to fiddle with buttons on the monitor to adjust it when I'm working at night.

Bad news: Now I'm faced with the "I can adjust brightness in software, but the internal monitor isn't synched with the external so I need to adjust both manually instead of just using the keys on the keyboard.

Good news: DisplayBuddy, which I'm trying a demo of, lets you sync an external to internal. Problem almost solved!

Bad news: In HDR mode, the monitor doesn't let you control anything about the picture quality--it's all software--and at the same brightness setting the external is somewhat dimmer than the external.

Thus, question: Are there any apps that let you offset the brightness of linked screens from each other? DisplayBuddy lets you link screen brightness, but doesn't let you offset the brightness between the two linked screens (that is, if the internal is set to 50%, the external is also 50%, you can't ask for 10% higher than the internal).

(I'm also a bit bummed that in HDR mode the monitor disables all picture adjustments, so software calibration is the only way to get the colors matched, which is proving to be very challenging when the brightness changes. And you can't adjust brightness in software if the monitor isn't in HDR mode, so SDR isn't really an option.)

 

[chown33]

This is just a guess, but if you attach a color profile to one monitor, would that conceivably get you the 10% offset desired? For example, if the profile is 10% brighter, and you attach it to the external monitor, does it maintain that difference when adjusting the two linked screens. Or attach a -10% profile to the internal, and see if it tracks.

The only other thought I had was contacting the DisplayBuddy developer and asking for an offset as a feature.

 

[Makosuke]

This is just a guess, but if you attach a color profile to one monitor, would that conceivably get you the 10% offset desired? For example, if the profile is 10% brighter, and you attach it to the external monitor, does it maintain that difference when adjusting the two linked screens. Or attach a -10% profile to the internal, and see if it tracks.

The only other thought I had was contacting the DisplayBuddy developer and asking for an offset as a feature.

The color profile is a good suggestion, which will probably involve figuring out how adjust those more manually than the standard or advanced OS calibrator allows.

I did try messing with gamma or white point in the calibrations, which helped a bit but didn't quite get me where I was hoping, and trying to mess with the color curve more precisely was extremely counterproductive--I could get it looking nice at one specific brightness level, but as soon as I adjusted it the curves went completely and unusably wonky. I get the feeling the old-school onscreen calibrator, as nice as it is, doesn't handle HDR well.

 

[chown33]

It's been at least 15 years since I even played with color profiles. I vaguely recall some apps that could adjust the color curves, but nothing whose name I remember. It was probably something oriented toward commercial artists or editors, which usually means it's pricey. It may have been a utility used with a screen calibrator, the kind that has RGB sensors that you hold up to a screen.

The one whose name I remember is the builtin ColorSync Utility, but it's for playing with profiles attached to images. I can't remember if it can adjust a profile's curves, or export one from an image.

Sorry that's not of more help.

 

[Makosuke]

After more digging, I think I've found an app that does what I want, BetterDisplay. It will take over the keyboard brightness keys to let you adjust brightness for either screen, but can also link them, but when they're linked it's relative not absolute. So I can set them to match then adjust up and down together. (It also has a whole pile of other tweaks that I don't need.)

I can't say it's quite perfect; the slope on the two screens doesn't quite match, so at low or high levels they deviate. Theoretically if it would let you adjust the absolute limits of each monitor (or the brightness curve) it would be possible to get them to go all the way up or down together, but that's pretty nitpicky. As is, it's fine in the midrange and I can just manually adjust the external at the extremes if I want.

Have yet to see how it handles auto-brightness changes, but it's looking promising.

The other more significant annoyance is that it looks like Safari now beachballs for maybe a second after a brightness adjustment; no idea what's causing this, and it's a bit annoying, but I don't adjust so often that it's a dealbreaker.

 

[Makosuke]

Minor follow-up: BetterDisplay Pro actually does something even more important than the brightness thing to make this a great monitor.

It has an option to change the color mode from 10-bit RGB to 12-bit YCbCr. I have no idea why, but setting that non-standard mode fixes the color offset issues I was having completely, and also appears to sync the brightness much better, so even with both screens set to the same % brightness they match surprisingly well.

The differing curve issue turned out to be because I had an option in BetterDisplay Pro turned on that let the internal screen go above 100% brightness, so each step was bigger than for the external. Once I turned that off (so both had a range of 0-100%), they now match more or less perfectly across the full range.

I have no idea why this monitor doesn't seem to be happy with 10-bit RGB input on the USB-C video port, but now that I have it dialed in it matches the internal very well in both color and brightness, so I'm happy.

 

[NauticalDan]

Came here to recommend BetterDisplay Pro. It seems like the most detailed and full featured app.

For any of the apps for this: Lunar, DisplayBuddy, BetterDisplay Pro, the devs seem to be pretty responsive and open to feedback. If you are looking for a feature request, don’t discount just asking. There’s some differences in functionality, but a lot of overlap too in them. I think some of the devs have agreed to not step on each others toes and some core features are likely to remain unique to a product based on their agreements.

 

[infinitedreams]

For any of the apps for this: Lunar, DisplayBuddy, BetterDisplay Pro, the devs seem to be pretty responsive and open to feedback.

DisplayBuddy support is nonexistent. The Windows version breaks the ability to take screenshots of specific windows in Snipping Tool. Have reported this to the developer but never got a response.