See the APUG thread Fotokemika...
Read carefully the posts by Mirko at ADOX Fotoimpex.
"They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."
— Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs