They are dichromats—with red and blue receptors—as opposed to most humans, who are trichromats with red, green, and blue receptors. So in terms of colors, they can distinguish roughly the same colors as a human looking through a magenta filter.
Except that a rose/red filter would pass wavelengths centered around red, while a magenta filter would block wavelengths centered around green. So a magenta filter would let in proportionally more blue.
They are dichromats—with red and blue receptors—as opposed to most humans, who are trichromats with red, green, and blue receptors. So in terms of colors, they can distinguish roughly the same colors as a human looking through a magenta filter.
Almost rose-colored glasses
Except that a rose/red filter would pass wavelengths centered around red, while a magenta filter would block wavelengths centered around green. So a magenta filter would let in proportionally more blue.