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dsolaris
Asked: 2019-09-30 14:17:50 +0800 CST

Ubuntu 19.04 has extra hidden gamma curve? (weird stuff...)

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As soon as i loaded my test image i noticed the gradient was no longer smooth but it contained some vertical artifacts. I should point out that the gamma is set to default in Ubuntu: xgamma gamma 1.0

I also have Windblows 10 and OSX and there the gradient is smooth. However in Ubuntu it is brighter and contains vertical artifacts. And each time i take a screenshot, test image becomes brighter. This is driving me crazy.

So here is a test image: Hi

Here is a screenshot from Ubuntu. Look into the black area and notice how an extra gamma is applied, reducing the amount of black compared to original. Also notice vertical artifact: enter image description here

Notice how bright the image becomes after a couple of screenshots (a screenshot of a screenshot of a screenshot to be exact): enter image description here

The test image in the last example has become stupidly bright indicating there is another layer of gamma control present in the display settings that is just hidden from access and is added to the previous gamma which was present in a screenshot.

Please keep in mind before you mention i should change gamma, this is all happening at gamma 1.0.

gamma 19.04

1 Answers

  1. My Ubuntu 16.04 can display your windows screen captures without grey scale gradients (what you call "artifacts" in FireFox. It's not Ubuntu it's the program you are using to display the grey scale.

    Try using Firefox or another image viewer instead of the one you are using now.

    Note: My gamma is also set at 1.0 but after the sun sets it gradually goes more red and less blue and a little less green over a 120 minute period on two out of three monitors. Gamma has never effected grey scale gradients though on any of the monitors.

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