Translation guide
How to express that something becomes red in Japanese, depending on what is turning red and why.
A literary or poetic verb meaning 'to become red' or 'to redden', often used for the sky or leaves.
空が赤む。
The sky turns red.
A person's face turns red from embarrassment, shyness, or anger.
Standard phrase for one's face turning red.
恥ずかしくて顔が赤くなった。
I was so embarrassed my face turned red.
A more formal or written term for blushing or flushing.
彼は赤面してうつむいた。
He blushed and looked down.
Literally 'to redden one's face', often used in literature or descriptive writing.
彼女は顔を赤らめて笑った。
She laughed, her face turning red.
Eyes become red from crying, lack of sleep, or anger.
General phrase for eyes turning red.
泣いて目が赤くなった。
My eyes turned red from crying.
Specifically means eyes become bloodshot.
徹夜で目が充血した。
My eyes are bloodshot from staying up all night.
A traffic signal changes to red.
The most natural way to say the light turns red.
信号が赤になった。
The light turned red.
Literally 'become a red light', also common.
交差点で赤信号になった。
The light turned red at the intersection.
Leaves change color to red in autumn.
The specific verb for leaves turning red/yellow in autumn. Often used for the whole process of autumn colors.
山が紅葉してきた。
The mountains are turning red (with autumn leaves).
Literally 'become tinted red', poetic and descriptive.
木々が赤く色づいた。
The trees turned red.
Metal turns red from heat.
Technical term for metal glowing red-hot.
鉄が赤熱している。
The iron is red-hot.
Means 'become bright red', can be used for heated metal in casual contexts.
ストーブが真っ赤になった。
The stove turned bright red.
赤くなる is the default for 'turn red'. 赤む is rare and literary. 赤面する is specifically for blushing (face).
彼は怒りで顔が赤くなった。
His face turned red with anger.
彼女は赤面して下を向いた。
She blushed and looked down.
In formal or written contexts, 赤面する is preferred over 顔が赤くなる for blushing. 顔が赤くなる is more colloquial.