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I really like f.lux, which is an app that automatically adjusts the display's apparent color temperature according to the time of day and location (so that the temperature is in sync with Sun).

How to set the color temperature manually? I.e. without f.lux?

Sometimes I'd like to have "tungsten" (2700 K) colors during the day or morning, which would require fiddling with the location coordinates in f.lux. Sadly, there's no "manual mode" that I'm aware of.

I'm looking for a OS X native / software based solution, that would allow me to set white point below 4500 °K, which is the minimum that Color Calibrator can set. Is this even possible?

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3  
Fellow f.lux user here. Great app. Best I know w/o 3rd party software or using the monitor's buttons would be to go System Preferences > Displays > Color > Calibrate. Use "Expert Mode". However this will only let you take it down to 4500 K. Interested to find out the answer on this one. –  boehj Apr 23 '11 at 20:23
    
Maybe I don't understand the difficulty, but can't you just set F.lux's daytime slider to 2700? When you say "sometimes", do you mean algorithmically predictable times/dates? If so, then a script would solve your problem. I think it's possible to write a script to force F.lux to a certain daytime temp (or nighttime for that matter). –  Kelvin May 18 '12 at 4:10

5 Answers 5

up vote 4 down vote accepted

This solution requires F.lux to be installed (I assume it's at /Applications/Flux.app).

Create a text file (let's call it flux-day-color) and put it in /usr/local/bin (usr is under "Macintosh HD" and may be hidden).

#!/bin/bash

if [[ ! -z "$1" && "$1" -ge 2700 && "$1" -le 6500 ]]; then
  defaults write org.herf.Flux dayColorTemp -int "$1"
  killall Flux
  open /Applications/Flux.app
else
  echo "provide a temperature between 2700 and 6500 (rounded to nearest 100)"
fi

In Terminal, run chmod 755 /usr/local/bin/flux-day-color

Now you can run flux-day-color 2700 in Terminal (or in another script) to change the day temperature. Note that the script restarts F.lux so you may see the display jump to 6500 K for a split second before applying your requested temperature.

It's also possible to schedule this to run at predefined intervals, but that's beyond the scope of this answer (and the question).

If you'd rather have a launchable app that can toggle between 2 temperatures,

Open Terminal and run these commands:

bash
cd /Applications/
mkdir -p flux-day-toggle.app/Contents/MacOS
cd flux-day-toggle.app/Contents/MacOS
cat <<END > flux-day-toggle

Now you'll see a greater than sign. Paste this:

#!/bin/bash

DOMAIN=org.herf.Flux
KEY_NAME=dayColorTemp

LOW=2700
HIGH=6500

cur_val=`defaults read $DOMAIN $KEY_NAME 2>/dev/null`
if [[ -z "$cur_val" || "$cur_val" -eq "$HIGH" ]]; then
  new_val=$LOW
else
  new_val=$HIGH
fi

defaults write $DOMAIN $KEY_NAME -int $new_val
killall Flux
open /Applications/Flux.app
END

Wait for the prompt to appear, meaning the file was written. Now the finishing touch:

chmod 755 flux-day-toggle

Now you can launch the new app. You can customize the LOW and HIGH settings to your liking.

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Here's a bonus tip: a command-line utility to set the display brightness (ie in lieu of the F1 and F2 keys). hints.macworld.com/article.php?story=20090901021817717 –  Kelvin May 18 '12 at 4:32
    
Had to check this as an accepted answer as I haven't got Nocturne to work on Mavericks. I enhanced your flux-day-color script a bit and created a Gist that can be used to set either/both day and night temperatures (and just using flux-temp 3000, i.e. without options, to change the current display temperature to whatever regardless of the time.) I also found out the minimum Flux temperature is 2300 K, at least in the current version. –  koiyu Nov 10 '13 at 13:54

When using the Displays section of your System Preferences, if you calibrate it, select show advanced options, one of the windows is this: enter image description here which to me looks like the white points you were looking for, be sure to uncheck "Use native white point" if you want to manually edit it.

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Great info, thanks. I hadn't had the guts to go through all the steps just for the white point. Sadly, though, the lowest kelvin is 4500-4700 (just closed the window ><). Is there a way to adjust just the white point? (well, I could calibrate different profiles) And how to adjust it below the Calibrator's options? –  koiyu Apr 23 '11 at 20:31
1  
I found the value hardcoded in /Users/username/Library/Preferences/com.apple.ColorSyncCalibrator.plist, but editing it to a lower value had no effect. I will keep looking. –  hobs Apr 23 '11 at 20:37
    
It did have an affect when I logged in and out, I was able to black out my entire monitor, so probably relauching something will reset the value –  hobs Apr 23 '11 at 20:41
    
I think I am going to need to ask my own question, something along the lines of what actions are the sys prefs taking after loading that file to tell the mac to activate the change besides changing the file. –  hobs Apr 24 '11 at 0:22

Found a possible workaround for those who are interested:

Nocturne by Blacktree

Nocturne preferences

It has a nice amount of options and is completely manual. Downside is it doesn't set apparent color temperature per se, but setting a white tint to RGB(255, 197, 143) has approximately the same effect as setting white point to ≈ 2600 °K (see Kelvin ⇔ RGB table on planetpixelemporium).

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Thanks - I'll check it out. :) –  boehj Apr 24 '11 at 13:22

Open system preferences, go to the Displays panel and choose the Color tab. Press the Calibrate... button and go through the steps. If you turn on expert mode, you will choose the white point using a slider, but if you don't you will get to choose between a few standard values. You can even do this multiple times, saving with a different name each time, and switch between them through the list in the color tab.

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Sadly, the lowest target white's are somewhere 4500–4700 °K. Do you know how to tune it down to, say, 2700 °K? –  koiyu Apr 23 '11 at 20:34

A cool way is to let f.lux do the work http://stereopsis.com/flux/ It adjusts your screen colour temp. with the time of the day! Give it a try!

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1  
I think you missed the part of his question where he said "without f.lux." –  Matthew Frederick Apr 24 '11 at 14:27
    
oh sorry... I realized it when I just had posted my answer –  Chris7opher Apr 24 '11 at 14:30

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