I think you'd be surprised at how light and subtle these things can be. I remember seeing some on something printed back in early 2000s and they were yellow dot

I think you'd be surprised at how light and subtle these things can be. I remember seeing some on something printed back in early 2000s and they were yellow dots barely registerable under a magnifying loupe, never mind by eye up close. Which, if the same sort of case here, makes the CCD(s) on the phone here particularly impressive.