Finding articles
Scholarly sources
Start by looking for scholarly articles in Art Full Text and JSTOR. A scholarly article will most likely be better for your assignment than a magazine or newspaper article, but you won't be able to find scholarly articles for every artist, in which case you will need to look in magazines and newspapers. Keep this in mind:
All the articles in JSTOR are scholarly.
You can limit to articles in scholarly journals in Art Full Text by using the checkbox for "Scholarly (Peer Reviewed) Journals" either in the advanced search screen or in the results list.
Some of the articles you will find in scholarly journals in JSTOR and Art Full Text will be exhibition reviews. These may not be the "very best article" on your artist, even though they appear in a scholarly journal. You will have evaluate all your options before you decide.
Summon (the search box on the library's home page) searches newspaper articles and will also find articles in JSTOR, but it does NOT search all the articles in Art Full Text.
Good sources for newspaper articles are Summon, New York Times Historical, and Nexis Uni (formerly LexisNexis Academic). For contemporary artists, check the artist's website for a list of articles that have been published about him or her, and see if you can find them online by searching in Summon.
Substantial sources
Length. Look at the length of the articles you find in your search results. Longer articles usually contain more substantial information. Scholarly articles are often dozens of pages long!
Breadth. Some articles discuss just one work or one part of an artist's career; others discuss the artist's entire body of work. Both kinds of articles can be substantial, but you will need to think about which might be best for your assignment. Substantial articles focusing on one work will contextualize that piece within the artist's entire body of work. If you find an article that discusses your artist along with others, make sure the section on your artist is substantial.