Strange artifacts ROG Swift PG278Q

[MMores]

Hello!

After thoroughly researching, I deciding that most the many issues with the PG278q would not bother me too much. (Pixel inversion etc) So I went ahead and bought it.

However, I've been noticing some rather strange artifacts on desktop wallpapers (as seen in the picture below). I don't know the name of this effect and I've never seen it to this extent. I was hoping someone here could explain to me what it is, and whether it's normal. I added a picture of the same image displayed on my 7-year old budget samsung TN monitor, which doesn't show the issue. Watch the gradient.

PG278q (the brightness is quite a bit higher than the Samsung due to old back lighting in the latter. Overall the image quality is not as bad as on the picture, but the mentioned effect is quite obvious):



Here is the same image displayed on a 7-year old budget Samsung TN monitor:



This is the original image:

If anyone could shed some light on this that would be amazing. Thanks in advance!

 

[aeliusg]

Looks like the wallpaper itself might be of rather poor quality. The one in your post is only 1280x720 and a jpeg at that.


Anyway, you should go here and take a look at the viewing angle and gamma calibration pages: Viewing angle - Lagom LCD test

Align your eyes with the panel so that the 'lagom' text fades away (with your eyes close to the monitor the text will not fade, but in between cyan and magenta you should see an obvious intermediate; with your eyes further away you should see the text fade to grey as described on the page).

Once you get the hang of what angle your eyes should be at so that you are not experiencing TN gamma shift on a given portion of the screen, go to the gamma calibration test page here: Gamma calibration - Lagom LCD test

Your should see the gradient blend together at around 2.2 with the PG278Q, which is known to have an excellent factory calibration. Make sure you realize that your eyes have to be level with the portion of the screen you are looking at for it to work, however. At standard viewing position e.g. with your eyes perhaps perpendicular to a portion of the panel nearer the top of the screen., gamma is shifted so that the screen as a whole appears brighter. This is inherent to all TN panels, and isn't really a problem unless you are supposed to be doing very particular work with colors.

 

[igluk]

Yes the image looks like this because of bad compression and the PG278Q has lower shadow gamma so the banding artifacts are highlighted.

I found a better version without banding, but it is the wrong resolution/aspect

 

[MMores]

Thanks for your reply. Apparently the forums won't let me upload the original picture in its original state. I will upload the picture to a host and edit the link into the first post. As you suspected the monitor has near perfect 2.2 gamma.

I realise this isn't a very good picture. However, I chose it because it clearly shows that sort of "digi camo" effect around the gradient. I'm seeing this effect in a lot of different circumstances, but this is one of the best examples. Another example would be this picture, in which you see the effects in the bottom middle, and to the left side of the leaf stem:

 

[MMores]

Yes the image looks like this because of bad compression and the PG278Q has lower shadow gamma so the banding artifacts are highlighted.

I found a better version without banding, but it is the wrong resolution/aspect

Wow this makes a world of difference. So if I understand correctly, the lower shadow gamma results in flaws in pictures being more highlighted?

This 'digi-camo' effect is nothing to worry about?

 

[igluk]

Wow this makes a world of difference. So if I understand correctly, the lower shadow gamma results in flaws in pictures being more highlighted?

Yes exactly. It also enhances artifacts in movies and such.
I use Calibrilla to adjust shadow gamma independently of the midtone/highlight gamma. (I prefer the lower shadow gamma, and higher rest gamma)
I don't know if there is a better alternative that's less cumbersome to use.

The digi-camo looks a bit like the effects of a deband shader, after running bad source material through madVR I get a similar effect.
Don't believe it is anything to worry about.

 

[MMores]

Yes exactly. It also enhances artifacts in movies and such.
I use Calibrilla to adjust shadow gamma independently of the midtone/highlight gamma. (I prefer the lower shadow gamma, and higher rest gamma)
I don't know if there is a better alternative that's less cumbersome to use.

The digi-camo looks a bit like the effects of a deband shader, after running bad source material through madVR I get a similar effect.
Don't believe it is anything to worry about.

Do you believe similar results can be achieved using a calibration device? Reading you guys' replies initially, I though I should just go and find a better quality wallpaper. However, the effect seems to show up in most dark wallpapers I can find. Maybe the 'lower shadow gamma' phenomenon is especially pronounced in my PG278Q, or maybe I'm just overly sensitive.

This leads me to wonder: is there any way to influence shadow gamma in the manner you described using a calibration device + software? I'm asking since I've attempted to use Calibrilla before and the GUI absolutely baffles me. I would not know how to use it to solely influence the shadow gamma. Every small adjustment I make in that program seems to have either no consequences or massive ones.

 

[igluk]

Yes, a calibration device would help, you should be able to set it so that it gives you a desired gamma curve.
It can do automatically what is manual and cumbersome in Calibrilla.
You can click on "Visual correction of LUT" select a single point or a range of points in the low 1-20 range of the gamma curve and then carefully adjust it with the rightmost slider.

 

[aeliusg]

You should turn down the brightness to start. I've had luck with DisplayCAL as well: DisplayCAL (formerly known as dispcalGUI)—Open Source Display Calibration and Characterization powered by Argyll CMS

 

[MMores]

Cheers for the advice! DisplayCAL is what I had in mind. Do you have any advice regarding DisplayCAL settings to address this problem specifically? I usually keep the PG278Q's brightness between 8 and 25 depending on the time of day.



EDIT:

igluk:

Unlike my last ventures with Calibrilla, I just seem to have succeeded. I even managed to reduce the effects in the above posted pictures dramatically! Thank you both again for the advice.

 

[cirthix]

check the nv control panel, you might have dropped down to 6bpc mode due to a dp connection issue