Reply To: Scanlines Issue – Gamma and Contrast Effected?

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Thank you very much for the information marqs!

Well, I’ve made a bit of a fool of myself. It is true that other than scanline opacity, the image remains the same. As I mentioned before, I’m primarily using OSSC on an HD CRT. Well, one thing I’ve always noticed with CRT’s and should have taken into mind initially is that when brighter images are shot into the tube, contrast increases and darker areas become even darker, sometimes black. And when the image coming into the screen is darker, contrast decreases and shadows are more visible. With scanlines at 100% it becomes half the image brightness than without scanlines. Reviewing the results on my LCD monitor, I am not seeing the drastic decrease in contrast as I was with the HD CRT.

I was strongly under the impression that when using a scanline generator on a CRT that the scanlines should be at 100% to be as accurate as possible. However, this is certainly not the case though. After fiddling a bit with the scanline generator in OSSC, I have found that 6% definitely looks too light on my Sony HD CRT. 12%, 18% and 25% look great though given the loss of Contrast in each step. Everything beyond 25% isn’t a very noticeable difference in scanlines and greatly reduces the contrast that this TV projects. Keep in mind I am strictly talking about the performance on my Sony HD CRT for attempting to make the scanlines look as much like a standard defintion CRT as possible.

Compared to one of my standard definition CRT’s without OSSC, I am finding the closest match is 18% Scanlines and Scanline Alignment: Bottom. This was when comparing the two inside the pause screen of Legend of Zelda: Ocarina of Time. In all honestly, it will come down to each TV and the user’s preference, but I’ve found these results to be satisfactory. Looking at the standard definition CRT, there were some areas in which the scanlines could hardly even be seen. I could barely see any scanlines in the green area of the Rupee counter at the bottom-left of the screen. And with OSSC on the Sony HD CRT the scanlines were fairly noticeable in that area even at 6%. Every TV is different though and again it’s really all about preference.

I did a full comparison of OSSC without scanlines, scanlines at 100%, and then the ‘scanlines at 100%’ de-interlaced. At this point I was absolutely certain that there were no other effects being applied to the image with increased scanline opacity. It was merely an effect of the CRT. Here is the comparison just for laughs lol.

Scanlines Comparison

Overall I am very happy with OSSC. It just took a little bit of tweaking to get the results I wanted it. I look forward to trying it out on some modern TV’s in the future. It’s nice to finally have a CRT that can display 480p along with 240p and 480i signals that look actually look accurate unlike the terrible built-in scalers of HD CRT’s.