blass
pale
Having a light, colorless complexion, often as a sign of illness, fear, or shock.
Sie wurde ganz blass, als sie die schlechte Nachricht hörte.
She turned very pale when she heard the bad news.

pale
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pale
Having a light, colorless complexion, often as a sign of illness, fear, or shock.
Sie wurde ganz blass, als sie die schlechte Nachricht hörte.
She turned very pale when she heard the bad news.

You can recognize the meaning of 'blass' (pale) from the context. If it refers to a person, it is about their complexion, often due to illness or shock. If it refers to an object or light, it is about a weak color. In connection with abstract nouns like 'Erinnerung' (memory), it is meant figuratively.
Nach der langen Nacht sah er müde und blass aus.
After the long night, he looked tired and pale.
To express the process of becoming pale, the combination with the verb 'werden' (to become) is often used. This describes a sudden change in facial color, usually due to shock, fear, or illness.
Als sie die Spinne sah, wurde sie ganz blass im Gesicht.
When she saw the spider, her face went completely pale.
A common idiom is 'blass um die Nase sein/werden' (to look/become pale around the nose). It means that someone looks sick, unwell, or frightened.
Du siehst aber blass um die Nase aus. Fühlst du dich nicht gut?
You look rather pale. Are you not feeling well?
In the figurative sense, 'blass' (pale) describes something unclear, lacking character, or not very impressive. It is often used with abstract nouns such as 'Erinnerung' (memory), 'Ahnung' (idea/notion), or 'Figur' (figure/character).
Ich habe nur noch eine blasse Ahnung, wie das funktioniert.
I only have a vague idea left of how that works.
deep
'tief' and 'blass' can form an opposite pair when talking about colors. A deep color is dark, rich, and intense. A pale color is light, weak, and not very strong. 'blass' is also used for a face when someone looks ill or frightened; in this use, 'tief' is not a normal opposite. For colors, however, the distinction is clear: 'tief' looks strong and dark, while 'blass' looks weak and light.

Am Montag trägt Lena einen blassen Pullover, der fast grau wirkt.
On Monday, Lena is wearing a pale sweater that looks almost gray.
Die Wand im Wohnzimmer ist in einem tiefen Blau gestrichen.
The wall in the living room is painted a deep blue.