> When converting to grayscale, you typically calculate the value of the pixel and then set all color components to that value. The point of this is to keep the luminance the same as it was in the original color pixel. If you’re doing this correctly, the perceived brightness stays the same.
This is precisely wrong.
To maintain perceived brightness, you want to set the color channels to the original value weighted by a scale factor that accounts for the eyes’ sensitivity to each color channel.
Fine, luma, not luminance. But what you're describing is exactly that calculation. This does not change my point. Again: If you’re doing this correctly, the perceived brightness stays the same.
This is precisely wrong.
To maintain perceived brightness, you want to set the color channels to the original value weighted by a scale factor that accounts for the eyes’ sensitivity to each color channel.