gradate verb. 
[grǝ'deɪt] M18.[Back-form. from GRADATION.]1.  verb trans. & intrans. (Cause to) pass by imperceptible degrees from one shade of colour to another. 
M18.■ J. Ruskin Take the two extreme tints and carefully gradate the one into the other.2.  verb trans. Arrange in steps or grades. Usu. in 
pass. M19.  [TahlilGaran] English Dictionary ▲