Tidak is used to negate verbs, adjectives and prepositions and a noun is negated with bukan. Both tidak and bukan can appear in one sentence.
Dia bukan seniman. Dia sama sekali tidak pandai menulis atau melukis.
He is not an artist. He is absolutely hopeless at writing or painting.
Dia bukan montir. Dia tidak bekerja di bengkel.
He is not a mechanic. He doesn’t work in a repair shop.
Ini bukan rumah Ibu Daulat. Rumah Ibu Daulat besar. Rumah ini tidak besar.
This house is not Mrs Daulat’s. Mrs Daulat’s house is big. This house is not big.
Ibu Daulat bukan tukang masak. Dia pegawai negeri. Dia tidak pandai memasak.
Mrs Daulat is not a cook. She is a civil servant. She can’t cook.
Maaf, majalah ini tidak untuk Anda. Anda bukan mahasiswa.
Sorry, this magazine is not for you. You’re not a student.
Kalau Anda bukan pemain, Anda tidak boleh turun ke lapangan.
If you’re not a player you can’t go to the sports ground.
Anda berkunjung ke pulau yang mana? Batam? Bukan! Batam tidak menarik.
Which island did you visit? Batam? No! Batam isn’t interesting.
Tidak never appears directly in front of any of these kinds of nouns. They are negated with bukan.
Although tidak is the usual negator for verbs, adjectives and prepositions, in certain contexts bukan can also be used to negate them. This happens most often when you want to emphasise a contrast, or when a contrast is implied.
Warnanya bukan merah tetapi hijau.
It’s not red, it’s green.
Hadiah ini bukan untuk kamu. Untuk Tanti!
This gift is not for you. It’s for Tanti!
Dia bukan mengambil uang. Sebetulnya dia memberikan uang.
She didn’t take money. In fact she gave money.
So it seems that bukan is a stronger, or more emphatic, negator than tidak, and for this reason can sometimes muscle its way into the negation of verbs, adjectives and prepositions, in addition to its normal function as a negator of nouns.
