Recommended settings for blueMSX to get the most realistic image (in my opinion).

Options->Settings->Theme: Select Terminal theme

After that

Options->Video


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"Terminal ADM-3A (Amber or BW) 1.0"

Monitor type: Amber or Black and white
Monitor emulation: Noisy Y/C cable (sharp)
Gamma: 0.82
Brightness: 0.74
Contrast: 1.50

Horisontal Stretch: OFF
Vertical Stretch: OFF
Scanlines: ON 50%
RF-Modulator: OFF
De-interlace: OFF
Blend consecturive frames: OFF