Ravil, if it referred to "student who HAVE TRANSLATED this article," would it be перевёдшие?

Uly, перевЕдшие

Thank you, the verb conjugator gave me the wrong information.

But isn’t переводившие used when they are in the process of translating?

Не за что). Yes, you're right, переводившие makes an accent on the process. Это причастие от глагола несовершенного вида.

Then my translation is correct?

Переводившие vs переводящие. The former refers to the past, the latter to the present. The Russian implies a past action.

So then how would you translate it?

... who translated/having translated¿

But how can it have a perfective meaning if it comes from an imperfective verb?

Hm... Maybe it's me.. When I see your translation, I start thinking about two simultaneous actions: some students are translating an article and they say it's quite difficult. Студенты, которые переводят статью, говорят, что она трудная. Is there a way to convey the precedence of переводившие over говорят.

When I look afresh at this sentence, maybe I agree with Tatiana.
Переводившие in Russian is not necessarily continuous. It may mean которые когда-то переводили not meaning the process, but the fact. Difficult to explain it...
It's like На той неделе мы ходили в лес (были в лесу)
Раньше люди писали письма друг другу, а теперь это редкость.

So, I'd translate this sentence as
The students who translated that article say that it's very difficult.

If it can mean которые когда-то переводили referring not so much to the process, as it does to the fact, then I would still use the gerund: "Students seeing the painting for the first time always think the woman is holding a cat, but upon closer inspection, realize that it's a possum." -similarly- "Students translating this passage always get caught up on the form "переводившие," which they find impossible to render correctly." Does that sound right?

"Студенты, когда смотрят на эту картину впервые, всегда думают, что женщина держит в руках кошку, но при более близком рассмотрении понимают, что это опоссум".
"Студенты, которые переводят эту статью, всегда спотыкаются на форме слова "переводившие". Они считают, что передать его смысл правильно невозможно".
На русском тоже получается настоящее.

So you can’t replace SEEING and TRANSLATING with participles here for that sake of argument?

We can, but it will be in the present tense.
Студенты, смотрящие на эту картину...
Студенты, переводящие эту статью...

I would say “My books have been translated into English. I want to introduce you to the person who translated them.”

I'd translate it in the same way.

Ok, I posted this on Russian Stack Exchange and got a very good response: https://russian.stackexchange.com/questions/17593/intepretation-of-the-imperfective-participle-%d0%bf%d0%b5%d1%80%d0%b5%d0%b2%d0%be%d0%b4%d0%b8%d0%b2%d1%88%d0%b8%d0%b9/17595#17595

It seems that this was my initial intuition - the students were translating the article at the time that they mentioned it was difficult, but we have no certainty that they ever completed it, which is why the imperfective participle is used, in which case “Students translating this article” would be in order. Does this sound correct?

t's correct theoretically, but in real life "переводившие" usually means a completed action, I don't know why. Like in Ravil's example.

Look at these examples, practically all of them refer to the completed actions http://search1.ruscorpora.ru/search.xml?env=alpha&mycorp=&mysent=&mysize=&mysentsize=&mydocsize=&dpp=&spp=&spd=&text=lexform&mode=main&sort=gr_tagging&lang=ru&nodia=1&req=%EF%E5%F0%E5%E2%EE%E4%E8%E2%F8%E8%E9

So then in practice there's no difference between переводившие and переведшие in this sentence and they could both be used interchangeably?

Yes, only переведшие is used more rarely

Ok, that explains that. So then my translation is invalid.

Just change it to the past simple

Done, thank you 😊

🌝 Thanks toTatiana, actually