The bitmap area of the Sinclair ZX Spectrum is exactly 256 x 192 pixels.
Surrounding the bitmap is quite a wide border area which is generally just one colour but loading and saving from tape changes the border colour quickly resulting in horizontal lines as thin as one pixel right through the border.
But what is the height of the border area above and below the bitmap area? I'm assuming it has a specified number of scanlines? And for horizontal border area on the sides I'm assuming it's specified as a number of bytes/characters, which are each 8 pixels wide.
But Googling I can't seem to find this specified anywhere. It must be quite well known for emulators etc. Perhaps it is the exact PAL spec, at least for the vertical? AFAIK the genuine Speccies were PAL only right?
I realize the full size of the border probably includes overscan beyond the size of our old monitors and TVs, if that's specified as well it would also be great to know.