The 0%, 50%, and 100% values in the above tables are "should-be" values. However, the real hardware doesn't exactly match that intensities. The actual intensities depend on the luminance mixing (R,G,B tied together via resistors), on chipset (classic CPC, or newer ASIC ones), and on the load applied by external hardware (Monitor, or TV set).
On an actual Amstrad CPC, the half-intensity colour signal is measured to be closer to 40% rather than the expected 50%. This was verified by Grim and independently confirmed by Nocash. [https://www.grimware.org/doku.php/documentations/devices/gatearray#inkr Source]
* [[CPC Palette]] - some more details
The R, G, and B values on This explains why the Amstrad Plus have been adjusted engineers used these values to adapt the old colour palette to the new 12-bit palette using a 4-bit scaleon the Amstrad Plus:
* 0% became #0
* 50% became #6
* 100% became #F
On an actual Amstrad CPC, the half-intensity colour signal is measured to be closer to 40% rather than the expected 50%. [https://www.grimware.org/doku.php/documentations/devices/gatearray#inkr Source] This is why the Amstrad engineers They specifically chose #6 for the 50% value instead of #7, to better match the real Amstrad CPC palette.
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