need help having a nightmare

[Unregistered]

i have just finished laying matt black riven porcelain floor tiles and have used black grout
i am founding it near enough impossible to get the floor tile black, i have washed them several times and allowed to dry but the tiles still look dirty and still get black coming off the tiles
can anyone offer some advice or possibly a solution to my dilemma

 

[Gazzer]

Can you explain your grouting method before we jump to assumptions.

 

[The Legend; Phil Hobson RIP]

Pics would help also the type of grout used eg Mapei/Bal etc.