Can strobe crosstalk get worse over time?

[turdas]

I have a BenQ XL2420Z that I bought in late 2014. I calibrated the crosstalk using the TestUFO Alien Invasion test and Blur Busters Strobe Utility soon after I got the monitor, and have been running it using the "Vertical Total 1350" trick as described in this article.

Recently I've felt like the crosstalk/ghosting has gotten worse than it used to be. When I first calibrated using the TestUFO test, I seem to remember having less ghosting in the middle of the screen, but now there's a fairly obvious effect. It's still different from the top and bottom, though, where the ghosting is (and always was) worse; along the top there's a "leading" ghost ahead of where the picture is in the middle, and along the bottom the trailing ghost is more noticeable.

Here's a couple of photos as well as I could get them using my phone camera. I couldn't get the camera to do a 1/120 second shutter speed so there's a little bit of extra rolling shutter artifacting from that, with the first picture being on a 1/118 second shutter speed and the second one being 1/235 or something:

middle of the screen, top of the screen


Of course it's possible, and in fact quite probable, that I'm only imagining things, too.

[Chief Blur Buster]

There are many theories, but a common one that creates subtle ghosting changes is...... Temperature.

Temperature changes can affect accuracy of LCD GtG transitions. In cold weather, LCDs run much slower and ghost much more, especially in a cold room.

Usually it will get worse in cold weather. But there are occasionally times if you calibrated an LCD during a specific temperature (e.g. 65 degrees F), you will get increased amount of coronas (overshoot) at higher temperatures (e.g. 75 degrees F).

Most of us are familiar with LCDs running very slowly in freezing weather (e.g. forgetting a smartphone in a car in the middle of winter, slow-responding LCD displays in freezing weather). Displays are also prone to this to a certain extent too, and manifests itself as increased ghosting/coronas (and also strobe crosstalk).

Make sure your monitor is fully warmed up, and make sure you adjust overdrive settings properly (in case they have accidentally changed), before you calibrate your strobe length/strobe phase ("Area"). Also, the longer the strobe length, the crosstalk becomes taller, so if you're using a brighter (longer) strobe length, you will have (slightly) worse crosstalk. So it's a tradeoff.

[Falkentyne]

That's inverse ghosting, not crosstalk.
As Chief said, monitor warming up can reduce this a little.

Other things you can do:
1) set contrast from 50 to 40 (this is mentioned in strobemaster's xl2411z article on his website).
2) when using blur reduction, set AMA to high AFTER enabling blur reduction, not before. This requires going in and overwriting the AMA high setting after enabling blur reduction. This trick does NOT work on V2 firmware. This requires V3 or V4 firmware.
Note that changing resolution, refresh rate or monitor brightness through the OSD, or ANY strobe adjustment (even by 1 point) will instantly revert this change and you will have to do it again.

Since you have the S-switch, you can also apply this "tweak" to blur reduction disabled, by doing 2) with blur reduction on, as above, and then activating an S-switch preset (that you PREVIOUSLY SAVED) that has blur reduction disabled in it. This has the greatest effect on the XL2720Z (the 27" monitor)--the improvement is massive in the XL2720z. On the XL2420Z (and XL2411Z) it's only slight.

On the XL2735 and XL2540 and XL2546 (three monitors which have removed the "Single strobe" option for 60hz, unfortunately) it's much easier to do this "Tweak"--you can go into the factory menu (NOT the service menu; the service menu has the strobe options, the factory menu has other bizarre options) and change the "Overdrive Gain" setting and get perfect ghosting.

[turdas]

Yeah, I suppose it's a few degrees cooler in my room during the winter, so that might explain it. Looking at some review pictures of the monitor there is similar levels of inverse ghosting in them, too, so I guess I might've just been imagining things.

Thanks for the replies.