Please don't necro threads that are two years old.
When you use your physical perception then things on the physical plane look solid and have actual tangible forms. You see (with your actual eyes) visual light (such as color and contrast).
When you switch from your physical perception to your astral perception you no longer 'see' the physical plane. Instead you 'sense' the astral plane. While using astral perception doesn't matter if you have perfect 20/20 vision or if your are blind (or if you close your eyes) on the physical plane. While astral is often explained as 'seeing' (because the metaphor works and because it is easier for most of us to understand) astral perception is a psychic 6th sense, different from your other 5 senses:
It takes a Simple Action to shift one’s perception from the astral to the physical, and another to shift it back again (it is not possible to see both at the same time, though almost everything in physical space is reflected on the astral, albeit without detail).
Astral perception is a psychic sense that is not linked to the character’s physical sight. A blind magician can still magically perceive the astral plane and the creatures and auras within. Likewise, deaf magicians can “hear” in astral space.
you’re not technically seeing them, but the analogy works
Technically, astral perception isn’t vision—you don’t need working eyes to see in the astral plane—but vision is the easiest metaphor to use.
Astral perception is a psychic sense, so where I see and hear light and sound, others may interact more through taste or texture. Your experience in the astral very much depends on who you are.
Since astral sight is not a truly visual sense, Awakened characters who are blind can still use astral perception all the time and at least have some sense of objects in the world, but gamemasters should apply the customary –2 dice pool modifier to all actions performed on the physical plane while perceiving the astral, including indirect combat spells, and keep in mind the differences between the astral and physical worlds.
Being dual natured, though, is different from astral perception in that a dual-natured critter always senses both the physical and astral worlds; they don’t have to shift back and forth (and, in fact, cannot do so).
The book describe the astral plane like this:
It is an emotionally charged photonegative of the physical world where only living things and things infused with mana are real and physical objects are mere intangible shadows.
The general aura of that life illuminates the astral world at all times with an ambient glow. Things that exist only on the material plane can be seen and heard from the astral, but they are blurred and muted as the emotional context of people and things registers more than physical properties of light and sound (in many ways they are a substitution for those properties).
Objects that are neither magical nor living do not have an aura; they are featureless grey shadows of their physical form.
Life illuminates and emotions color a grey and shadowy mirror of the physical world. When astral projecting, you do not hear the din of the physical world, nor can you read written words. Technological displays and holographic images don’t exist even as shadows on the astral plane. All the lifeless objects in the physical world appear as dull and intangible shadows to astral forms, allowing them to easily pass through. Details on these objects (color, texture, smell) are almost impossible to understand; a book’s words are impossible to read, as is the context of the writing unless it’s tied to some emotion that the character can perceive. All life has intangible auras that illuminate the astral world, while emotions can color them. Emotions can also color non-living objects if they have some significance to metahumanity (individually or as a whole). Within the silence, the magician can hear the crackle and hiss of mana being drawn into a spell or the subtle harmonies or cacophony of aspected mana as it flows through the astral plane.
When you look at a room with your regular perception you could for example see a red bench with two people. You see a yellow desk and you see a green poster on the wall with some white text that you can read. Spotlights in the ceiling lit up the room. If you close your eyes everything goes dark.
When you switch from your physical perception to your astral perception, while still keeping your eyes closed. You 'sense' (which is different from 'seeing') the walls, the bench and the desk, but they appear to be intangible colorless shadows of their former self - you get the feeling that you could walk straight through them (and if you were projection you actually could). You almost can't distinguish the poster on the wall from the wall itself and the color, contrast and text is no longer there. Everything is lifeless and colorless, except for the two living subjects on the bench. While they too are just represented by intangible blurred shadows they are full of emotions and they also have an 'aura' full of life which make them quite obvious compared to their lifeless mundane surrounding.
Now you open your eyes on the material plane, while still using astral perception. And nothing changes. At all. You are still using astral perception instead of your regular perception. You still can't read the poster. You still can't see the color of the bench. You still can't see the bright light from the spotlights in the ceiling (instead the room still appear to be 'lit up' by the two living subjects on the bench).
You can navigate through the room or even bring up your gun and aim at one of the subjects on the bench, but since you are using astral perception instead of physical perception you will take a negative dice pool modifier of 2 dice (due to the disorientation). It would also not matter if someone would turn off the spotlights in the ceiling (or if someone blindfolded you). While the room would turn into total darkness on the material plane which would cause a negative dice pool modifier of 6 dice (Blind Fire) for anyone using their regular perception, you would not even notice that the room turned dark and you would still 'only' have a negative dice pool modifier of 2 dice from using your astral perception.
