The difference between CLOB and BLOB / BFILE is that CLOBs are treated as Text. That is, if you pull the CLOB from the database, it will do any conversion necessary from the database character set to the client character set (for example, removing the accent from ê). Similarly, when a CLOB is created by the client, there may be a conversion from the client character set to the database character set. If both client and database character sets are the same, then no conversion is required or is performed.
NCLOB is similar to CLOB, except that instead of using the database character set, the conversion uses the NLS NCHAR character set.
BLOB / BFILE will not obey conversion rules.
, GENERALY CLOB , /, , BLOB/BFILE. RAW.