Translation guide
In Japanese, the English word 'pastel' is used in several ways: to describe soft, light colors; to refer to the art medium (pastel crayons/chalks); and in compound terms for pastel-colored things. The most common and natural way to express 'pastel' as a color is the loanword パステル, often combined with カラー or used as a prefix.
Describing a color that is soft, pale, or light, like pastel pink, pastel blue, etc.
The most common way to say 'pastel' as a color. Often used as a noun or prefix. Can stand alone or combine with color names.
I like pastel colors.
She is wearing a pastel pink dress.
Means 'pastel-toned' or 'in pastel shades'. Used to describe an overall pastel look.
This room is decorated in pastel tones.
Literally 'pale/light color'. A native Japanese alternative to パステル, though slightly broader. Can be used for any light, faint color.
Pale-colored flowers are blooming.
Loanword 'soft color', sometimes used in fashion or design contexts, but less common than パステル.
Soft-colored knits are in fashion.
Referring to the art supply: pastel sticks or chalks used for drawing.
Naming a specific pastel color, like 'pastel green' or 'pastel yellow'.
Prefix パステル + color name. Very productive and natural.
The pastel green walls are refreshing.
I bought a pastel yellow blouse.
Prefix 淡い (pale) + color name. More native Japanese feel, but less specifically 'pastel'.
A pale blue sky stretches out.
パステル is a very common loanword and is understood by most Japanese speakers. It's safe to use in both casual and formal contexts when talking about colors. For the art medium, context will clarify whether you mean the color or the crayon.
パステル specifically implies a soft, milky, often trendy pastel shade. 淡い simply means 'pale' or 'light' and can describe any faint color, including faded or washed-out tones. Use パステル for the fashionable, cute pastel aesthetic.
Pastel-colored sweets are popular.
Pale-colored T-shirts fade quickly.
She decorated her room in pastel tones.
I want to try drawing with pastels.
展覧会で美しいパステル画を見ました。
I saw beautiful pastel paintings at the exhibition.