This is the procedure to follow when you upload from Pixiv:
- Do a source search for the Pixiv username. The username is found in the source URL. I.e., search source:*shirononochiko* if the URL is http://img13.pixiv.net/img/shirononochiko/2191076.jpg.
- If you find any posts and they already have an artist tag, use that tag. You will need to update the artist entry so that Find Artist will work with this artist in the future. More on this later.
- If this search didn't turn up any posts, or you find posts but they don't have an artist tag, then you will have to make a tag yourself. Edit the post and add artist:artist_name to the tags. More on coming up with the artist name in a bit.
- After you make a new artist tag, you will also have to edit the artist entry. Do this by clicking the '?' next to the artist tag in the tag list. More on filling out the artist entry later.
Artist naming
Figuring out the right name for the artist is a bit of a howto in itself, as artists often have several different handles. The easiest thing to do is to use their Pixiv username (again, found in the source URL). This name is unique across Pixiv, so if you use this you usually don't have to worry about conflicts with other artists on Danbooru.
Your next choice is their Pixiv nickname (found under their profile picture). This name is not unique (multiple Pixiv artists can have the same nickname) and artists can (and do) change their nickname, so this is often not the best choice.
Finally, if the artist has an external website you can try to find their real name there, or you can just use their site name. If you can read Japanese you'll probably find a better name on their site than on Pixiv, but if you can't read Japanese you're probably better off just using their Pixiv username. There are sites for romanizing kanji artist names, but it's probably a bad idea to rely on these if you don't know any Japanese.
If you are romanizing an artist's name, be sure to follow Danbooru's romanization guidelines. Unfortunately, these aren't written down anywhere so someone else will have to explain them.
If the artist name conflicts with another tag on Danbooru you'll have to add a qualifier to disambiguate the tags. When doing this you can use any of the information found above as a qualifier. For example, if the artist's Pixiv username is 'foo' and their site name is 'bar' then the tag could be foo_(bar). Do not use the Pixiv ID as a qualifier (i.e., don't make tags like name_(pixiv1234)). Do not use _(pixiv) as a qualifier either.
Artist entries
The most important thing you need in an artist entry are the URLs of any sites the artist uses to host their work. These are necessary for Find Artist to work. For Pixiv artists, this means you need to include the source URL of one of their pictures (i.e., http://img13.pixiv.net/img/shirononochiko/2191076.jpg). You should also include the URLs of any other blogs or personal sites the artist uses. It is also helpful to include a link to the artist's Pixiv profile.
Finally, you may also list the artist's name in kanji/kana under 'Aliases'. Make sure the alias isn't already in use. An alias can only be associated with one artist entry. If you add an alias to an artist entry, and that alias was already used by another artist, then the alias will be silently removed from the old artist and added to the new artist. Search the artist database first to make sure the alias isn't already in use.