A group lobbying for affordable textbooks criticized digital "e-books" Friday, saying they are missing the opportunity to provide cash-strapped college students with a more affordable option.

Universities should take a page, instead, from the "open textbook system," which offers materials written by professors online for free, according to the Colorado Public Interest Research Group.

A report released by the University of Colorado's CoPirg chapter slams e-textbooks for being too expensive. The average e-textbook surveyed costs the same as a new hard copy of the same title bought and sold back to the campus, according to the report. And 75 percent of the e-textbooks surveyed expired after 180 days, leaving students with nothing to sell back or access in the future, the study found.

"Digital textbooks could be a solution to the textbook affordability crisis, but unfortunately publishers are still heading in the opposite direction," said Max Gompertz, a CU sophomore and CoPirg intern.

The study consisted of a survey of 504 students from Illinois and Oregon, and an analysis of the print and e-textbook versions of 50 commonly assigned textbook titles.

CU's bookstore began offering e-books two years ago, but students still overwhelmingly prefer traditional copies of the books. The store sold only about 70 e-book titles this fall.

CU Professor Michael Klymkowsky provides the materials for his biology fundamentals course on the Internet, which he said saves his students money.

"Many textbooks in many classrooms are not used effectively," so they are not worth the money spent, he said.

Klymkowsky said he believes some professors assign textbook readings as a mere obligation. He acknowledged that some textbooks are essential to classes, but he said others cover some topics or ideas not applicable to the course, which can distract students.

Klymkowsky said faculty members, many of whom aren't aware of the cost of textbooks or the availability of alternatives, need to better assess the value of using a printed textbook.

CoPirg is pushing for an open textbook system, which would offer materials written by professors online for free. The method would require professors to give up authorship rights, but companies like Flat World Knowledge work with professors to compensate them, Gompertz said.

Still, some students find that printed textbooks are more convenient.

"I like having concrete things in front of me, and it hurts my eyes to read the (computer) screen," said Rachel Cole, a CU sophomore. "I feel like textbooks are the backbone of courses and that most of what I read in them enhances what I'm learning in class."

CU junior Michelle Benson said most of her professors scan the reading materials and post them online so students can access them for free. "I don't buy new textbooks. It's not worth it to sell them back for a fraction of the cost," she said.

An average student at a public, four-year school will pay $900 a year for books, according to a federal report released last year.

A new Colorado law requires publishers to "unbundle" textbooks so students are no longer forced to buy expensive extras, such as CD tutorials, which come packaged with their books. The law also requires publishers to tell professors a textbook's price, how long the edition might be kept on the market and a history of previous revisions.

Contact Camera Staff Writer Brittany Anas at 303-473-1132 or anasb@dailycamera.com.