>>1017871
According to the devlogs for Quake it was Adrian Carmack and Kevin Cloud who where the texture artists.
They painted everything by hand in Photoshop 2.5/3.0 running on SGI and Windows NT workstations.
There isn't anything magic or exotic to it but they restricted themselves to a 256 color palette
handled thru a custom tool written by John Carmack that handled that as well as saving to Quake's .wad format.
The colors chosen was a range they knew would help ask the texture seams.
Over at Epic it is stated it was Shane Caudle who painted nearly everything for the original Unreal.
He used 1996 Photostop 4.0 on a PC. He had custom tools that packed the textures into the .utx format and generated mipmaps.
He stated in interviews he painted his textures at higher resolution and downscaled to the res used by the game.
You can do anything they did back then better in standard photoshop of today.
If you wanna be early Quake 'Photoshop 2.5 authentic' just don't use any layers as you didn't have those until 1994 and 3.0