Some question aren't asked that frequently, but I'll just add it for no reason.
Last FAQs update : 28 July 2019
What are the requirements?
Minecraft 1.7.10 or above.
Optifine (Latest version recommended).
NVIDIA GeForce GTX750 or anything similar or even better.
I got a config (shader options file). How do I install it?
Put the config inside .minecraft\shaderpacks
Rename the config to the shaderpack's name (extension included, ended with .txt)
Example: BSL v7.1.zip uses a config named BSL v7.1.zip.txt. BSL v7.1 uses a config named BSL v7.1.txt.
Choose BSL Shaders
What are the recommended video settings?
Graphics : Fancy
Render Distance : 8 or above
Smooth Lighting : Maximum
Smooth Lighting Level : 100%
Dynamic Lights : Fast / Fancy
Sky : On
Can I run this in Minecraft 1.x.x?
Shaderpacks are usually not affected by Minecraft version. The lowest version I recommend is 1.7.10 though.
Is there any issues on certain Minecraft versions?
1.7.10 - somewhere below 1.7.10
Double plants don't get marked as foliage.
Custom alpha checking for weather isn't used.
Any incompatibilities mentioned above.
Why v7.0 and below have static foliage and vanilla water?
Minecraft 1.13 removed numerical block IDs which causes this issue if the shader doesn't provide its own block ID mapping. As of 1.14.2, Optifine added automated block ID mapping which fixes this issue.
There is only one zip (per version). Where can I get lower / higher quality of it?
You can change it through Shader Options. It allowed me to set up multiple quality "Profiles" in one zip, which allows easier distribution.
Should I change render quality and shadow quality in Shaders menu?
Render quality, you can lower it for sure. However, I'd recommend using the built in anti-aliasing (FXAA or TAA) instead of higher render quality since it's cheaper.
Shadow quality, don't. You can change it through shader options. Shadows > change Shadowmap Resolution and/or Shadow Distance.
My top half of the sky is broken.
Video Settings > Details > enable Sky.
I don't bring light sources and caves are too dark.
Video Settings > change Brightness.
This shader uses similar brightness to vanilla on caves (unless you change certain settings).
I turned on Round Sun & Moon and I still see vanilla sun & moon.
Optifine doesn't support vanilla sun & moon toggle based on shader options, you need to disable it manually. Video Settings > Details > Disable Sun & Moon.
The leaves are bright/unshaded.
The bright part are meant to be transparent. However, using fast leaves causes the transparent part to appear. The shader doesn't apply lighting on those transparent part which causes the issue.
Video Settings > set Graphics to Fancy,
Video Settings > Details > set Trees to Default / Fancy.
The shader is blurry. I don't like it.
Shader Options > Post Process > reduce Bloom Strength, or disable Bloom.
The shader is too blue / bright / anything else related to color and brightness.
Shader Options > Color > change the settings as you see fit.
Why some blocks like glowstone and sea lantern are tinted yellow?
I tinted it to make it look more consistent with the blocklight color. You can disable it through shader options. Shader Options > World > disable Emissive Recolor.
Why everything looks dull at night/when raining?
I tinted everything to give a more atmospheric feel. Again, you can disable it through shader options. Shader Options > World > disable Desaturation.
I use resourcepack with specular and normal map, but nothing happened.
Due to performance cost, extra effects which can be achieved with specular and normal map are disabled by default, you can enable it through shader options. Shader Options > Visual > enable Resource Pack Support.
I enabled Black Outline and I see patterned outlines on water and lava. It's disturbing.
Shader Options > Waving Blocks > disable Water and Lava.
My screenshot is bright for no reason. It's fine ingame though.
You have both Screenshot Size and Auto Exposure enabled. Disable Auto Exposure, you can change the expsure manually. Shader Options > Post Processing > Color Grading & Tonemap Config > change Base Exposure
My sky is broken and I use mods.
I have Astral Sorcery.
Open the mod settings, set weakSkyRenders to 0.
I have Advanced Rocketry
Open the mod settings, disable overworldSkyOverride.