Although the ZX Spectrum screen fits in 240p, uploading it to youtube at this resolution destroys the image. The video compression halves the chroma component, so all colour transitions become very blurry, especially dark colors like blue, red and magenta on black. It’s always better to upscale the image beforehand (2×, 3×, or even better 4x, nearest neighbour). Make sure you capture the screen in a lossless format without chroma halving.
Although the ZX Spectrum screen fits in 240p, uploading it to youtube at this resolution destroys the image. The video compression halves the chroma component, so all colour transitions become very blurry, especially dark colors like blue, red and magenta on black.
It’s always better to upscale the image beforehand (2×, 3×, or even better 4x, nearest neighbour).
Make sure you capture the screen in a lossless format without chroma halving.