Tinta vs. pintura
In Portuguese, while both tinta and pintura relate to paint, they are not interchangeable. Tinta refers to the physical liquid or substance itself, while pintura refers to the act of painting or the resulting layer of color on a surface.
Tinta
A2This word refers to the physical, raw material used for coloring. It is the liquid, paste, or powder you buy in a can, tube, or cartridge. Think of it as the product.
Preciso comprar mais uma lata de tinta azul.
(I need to buy one more can of blue paint.)
Cuidado, você pode manchar sua roupa com essa tinta.
(Be careful, you might stain your clothes with that paint.)
A impressora está sem tinta preta.
(The printer is out of black ink.)
Ela comprou uma tinta de cabelo loiro platinado.
(She bought a platinum blonde hair dye.)
Vamos usar tinta para tecido para customizar as camisetas.
(We are going to use fabric paint to customize the t-shirts.)
Pintura
B1This word refers to the result of applying paint. It is the finished layer on a surface, the paint job itself, or the act of applying paint. It can also mean a work of art (a painting).
A pintura da parede ainda está fresca, não toque.
(The paint on the wall is still wet, don't touch.)
A pintura do carro ficou excelente depois do polimento.
(The car's paint job looked excellent after polishing.)
A pintura da casa vai demorar todo o fim de semana.
(The painting of the house will take the whole weekend.)
Com o tempo, a pintura do portão começou a descascar.
(Over time, the paint on the gate began to peel.)
A Mona Lisa é a pintura mais famosa do museu do Louvre.
(The Mona Lisa is the most famous painting in the Louvre museum.)
Summary
In short, you buy tinta (the substance) in a store to do a pintura (the action of painting), which results in a pintura (the finished coat) on a surface.