How should I understand the use of particle に in the context of 受身形 and 自動詞 in these sentences?

Question

• 夕焼けに染まる
• 夕焼けに染められる

I got both examples from here and here respectively. I understand what these sentences mean, but I'm a little confused as to how sentence particle ’に’ works in these sentences. If both of the 自動詞 and 受身形 make use of particle に, does that mean 自動詞 and 受身形 are exactly the same? If so how could we differentiate the use of 自動詞 or 受身形, or to be clear, why would there be two different forms? Shouldn't there at least be like a difference in nuance?

Is there a difference in nuance for both these sentences? Is it that one is more commonly used than the other? Any difference in meaning for both of them?

Also, how would you understand the use of 'に' here? If we were to translate them literally, do they both mean "by" in English? Or is there something else I don't know about?

Sorry if it sounds like a dumb question, but this has been troubling me for a long time.

Answer 1

First, a small list of grammar terms needed to read both OP's question and my reply.

[自動詞]{じどうし} = intransitive verb

[他動詞]{たどうし} = transitive verb

[能動形]{のうどうけい} = active voice form

[受身形]{うけみけい} = passive voice form

Now, the phrases in question:

1) [夕焼]{ゆうや}けに[染]{そ}まる

2) 夕焼けに染められる

OP says "自動詞 and 受身形" a few times, so it would not be a typo. The truth is , however, neither of the two phrases in question is a combination of 自動詞 and 受身形.

染まる is a 自動詞. = "to turn color"　

染める is a 他動詞. = "to dye something (a particular color)"

「夕焼けに染まる」 is a combination of a 自動詞 and 能動形. Something turns color against or because of another thing.

↓↓

"Something turns color with the evening glow." (It is that something that is doing the action.)

「夕焼けに染められる」 is a combination of 他動詞 and 受身形. Something is made turn color by another thing.

↓↓

"Something gets bathed by the evening glow." (It is the evening glow that is doing the action.)

We have two different に's here.