Types of observations

Hi,

I hava a question about the 'webops (indivitual) submit form',( http://www.aavso.org/webobs/individual [1] )

About the first question: What type of observation are you submitting?: *

The possible answers are not all clear to me
Answers (=what i :

• Visual (=naked eye = I get that)
• CCD (=expensive chip photography = I get that)
• Reduced PEP (=?What is that?)(EDIT: i just found what this is,  but i think many new people wonder.  http://www.aavso.org/content/aavso-photoelectric-photometry-pep-program [2] )
• Photographic (=? same as CCD?)

So, if you could explain the last 2 in short that would be verry helpful

2nd