[T-Mobile Samsung Galaxy S II SGH-T989] cheema:
Update

Feedback from many users of Samsung Galaxy S II phones appears to suggest that the display calibration problem is prevalent mostly in Qualcom based units. These include models from:

1. T-Mobile USA

2. AT&T Skyrocket

3. Telus Canada

4. Rogers Canada

The Exynos based Samsung Galaxy S II phones are known to be calibrated considerably better. These include models from:

1. Sprint

2. AT&T (non-Skyrocket model)

3. International version

End update

Many people are complaining about the quality of their T-Mobile SGSII displays. I noticed the problems myself and decided to perform some detailed testing.

Here is how you can reproduce the simple test:

Download the blobs.jpg to your phone. A copy of blobs.jpg is attached here. Or simply point the browser on your phone to: http://cheema.com/blobs.jpg Tap and hold the dark gray rectangle and then select "Save image" from the menu. Note that it is not entirely black. It is dark grey. Testing with a black screen gives you false hope that your display is good.

Turn off automatic brightness and dial down the brightness all the way to make it as dark as possible. Go to Home->Settings->Display->Brightness.

Open up the "Gallery" application and locate the blobs.jpg in the download folder and view it in a mostly dark room.

At this point you'll probably see a greenish display with vertical lines and dots all over. If you see this you have what some of us call a bad/non-calibrated display. Based on the data I have seen so far, I think that all T-Mobile Galaxy S II owners suffer from this. Most people believe they have a good display because they do not have a the equivalent Sprint phone to compare with.

Results of detailed testing of T-Mobile SGSII screen

I performed the detailed tests with a total of 4 units. 2 from T-Mobile and 2 from Sprint. I set all phones to identical brightness level (lowest) and proceeded to run a few screen tests.

1. Blobs test

For this test I used Gallery application to display the blobs.jpg file attached here. [Click the pictures to see the full size versions]

I slowed the camera shutter down good bit so that I could see details that are not be visible to the naked eye. One thing was pretty clear, the Sprint phones (#1 and #3) had imperfections too. Lines and blobs. This made me think that perhaps all Super Amoled displays have them. However the reason nobody sees them on Sprint phones is because their displays are properly calibrated with correct contrast, saturation and color temperature values.

This is pretty close to what you see with a naked eye:

2. Reading test

For this test, I simply loaded up a web page that I was reading earlier and found difficult to read on T-Mobile SGSII. http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/

This was the deal breaker for me. Click on the image above for the full size and the compare the last 2 phones. This problem cannot be fixed by cranking up brightness. As that brightens up the text too. And you want the text to stay black and sharp for good contrast.

3. Picture test

For this test, I grabbed a picture from Flickr and displayed it on all phones.

For this test, you probably should look at the larger shot, before drawing any conclusions. The smaller picture simply does not show enough detail.

While none of the phones in the picture test show entirely correct colors, the Sprint phones do a commendable job. "T-Mobile 2", goes off the deep end and shows the tree to be mostly green, when in reality it is mostly yellow.

4. Front camera test

For this test, all 4 phones were switched to front camera and the camera settings were reset to default. I then put the phones down on a table and took a picture with my Canon 60D. By now I was not expecting any miracles and I did not get any.

T-Mobile units continued to show that they were not loved by their creators. On a side note, I am beginning to think that the T-Mobile units may also have something wrong with the front cameras. I'll have to set aside some time to perform detailed front camera testing for comparison with the Sprint phone.

Conclusion

In an earlier post I stated my belief that all T-Mobile SGSII phones have screen problems that do not exist in the Sprint version. These tests with additional units back up that belief. There is no good way to explain the consistent bad performance of T-Mobile phones when compared to the Sprint phones. While we do find the lines and blobs present in the Sprint phones too, their presence is inconsequential. Proper calibration of the display masks these lines and blobs. The T-Mobile phones unfortunately suffer from incorrect display calibration. Some are much worse than the others. Many will continue to claim that their T-Mobile phones do not suffer from the same problems as the two units I tested here. While statements like "My phone looks OK to me" are well and good for the individual user, they are not scientific. I invite any skeptic to find a Sprint SGS2 and put their T-Mobile unit next to it and run these tests. And then come back and show us the results. I would genuinely be surprised and happy if any T-Mobile SGSII phone out there behaves differently from the ones I tested.

I do not know if the incorrect calibration can be fixed with a software update. I hope that it can be. It would certainly save an otherwise awesome phone.

I would be open to trying a different test with all 4 of these phones and compare output. Let me know if you have a specific test in mind. In the meantime, I will probably run a few more tests and will update this post with new data, as it comes in. I will also be happy to update this post, once anybody finds solid evidence of a single T-Mobile SGSII phone with a good display.

My hope with this post is that we raise awareness of the issue so that people building and shipping these phones wake up and fix the problem. If we continue to pretend that the problem does not exist, then it most certainly will not get fixed.

FYI: article on engadget http://www.engadget.com/2011/11/08/t-mobile-galaxy-s-ii-screen-issues-have-some-seeing-poorly-rend/