Deleter is a Japanese brand of paper made for comics. It comes in a range of sizes and weights – including one in the standard postcard format – that I have used at times.
Here is a scan of the label/info sheet that was included in the package.
And like any product one purchases, it is important to know how to use it. For that it is imperative you read the small print.
I had a look at the English text and liked what I read, especially the sentence that says: “For the process of paper procreation, tiny dots might be mixed in.”
Here’s a larger version for your enjoyment too: