Well there certainly have been a great many such postings...even dedicated Threads, over the last several years, but t's no help that the AVS Google Search isn't available either. But perhaps you should read the " Guide to DIY Screens" sticky authored by Tiddler.
Do that first then you can come back with at least a basic understanding.
The most basic thing? Excessive Sheen effectively reduces Contrast. Just the right amount can sharpen an image, maximize available gain, and help accentuate contrast by helping brighter areas "stay bright" but not make darker areas "shine".
Most screens that actually use sheen are darker Gray examples, exactly for the reasons outlined above.
Do that first then you can come back with at least a basic understanding.
The most basic thing? Excessive Sheen effectively reduces Contrast. Just the right amount can sharpen an image, maximize available gain, and help accentuate contrast by helping brighter areas "stay bright" but not make darker areas "shine".
Most screens that actually use sheen are darker Gray examples, exactly for the reasons outlined above.