Preliminary assessment of paintings
 

Dear experts in the assessment of painting (or rather art ) , is it possible to get yourself a small educational program on this issue?
At least the basics ..
Please tell me exactly how factors such as the age of the picture , the name and status of the artist, subject , size, fabric , etc., affect the price of the painting ? In other words, we would like to find out a brief assessment algorithm (I understand that clear boundaries there can not be, but nonetheless , at least in general terms ) .
 Thanks in advance .