John Knaur, the company's senior product manager for digital cameras, says he's seen such "orbs" before.

"They're particulate matter of some sort such as dust, or pollen or moisture -- all it needs is a little bit of reflective value," he says of some of the images. "I don't disbelieve in ghosts, but this is dust."

Knaur says other orbs look like enlarged reflections from sap on broken branches. He explained that pixels in digital camera sensors, exposed to intense light, can "bloom" and spill their contents to neighboring pixels.

Similar orbs, although not as bright, might appear on images shot with film cameras too, he adds.

Fisher doesn't buy the brushoff. Why, he asks, did we get dust particles only when the other measuring equipment seemed to indicate spirits? Moreover, he notes, both he and fellow ghost hunter Scott Ditmer recorded the orbs with their cameras from different angles.

In addition to still photographs, Fisher has taped orbs zipping and floating around rooms with a Sony camcorder -- a phenomenon with no immediate rational explanation. In fact, the Web has several videos shot by ghost hunters' camcorders displaying orbs in motion similar to the ones in the E-20N photographs.

Fisher didn't pick up any orbs with his camcorder on this night, given that it was pointed away from where the globes of light appear in the pictures. But in the first couple of minutes of camcorder taping, a woman's voice can be heard softly saying, "Cobal," which he believes may be a last name -- possibly of someone buried in the cemetery. It is a clear example of EVP.

While some ghost hunters have proffered protocols for all to follow -- such as not smoking during an investigation so no one mistakes cigarette smoke for ectoplasm -- no one is bound by the rules.

And a few debates still rage about what the protocol should be in some instances. For example, some hunters believe digital cameras fail completely as evidence-collection tools because there is no negative to be reviewed.

Author Katherine Ramsland, who wrote the book Ghost about her experiences hunting spirits, remains skeptical of some claims.

Orbs in photographs were not what she was expecting when she went looking for proof that ghosts exist.

"I still want to see a ghost or get knocked around by a ghost," says Ramsland, who teaches forensic psychology at DeSales University in Center Valley, Pa. "I want to see something that is real and supernatural. I've seen things that were ambiguous, but I want clarity."

For now, the most persuasive evidence may be EVPs, the sound recordings.

"EVP is the best ... they're real voices," Ramsland says of the purported ghost voices collected on tapes and digital recorders. But just whose voices or where they're coming from isn't clear.

Mark Nesbitt, who does a little bit of ghost hunting from time to time, likes EVP, too. He has collected several recordings at several places around the sprawling battlefield where 6,000 to 8,000 soldiers died. He has received responses before from Thomas Ware, who fought with the 15th Georgia Volunteer Infantry regiment and died in the Triangular Field.

"I'm still a skeptic, but you can't deny what you see and record on tape and film," says Nesbitt, who has written books on the Civil War and runs the Ghosts of Gettysburg Candlelight Walking Tour service.

"I've collected almost 500 ghost stories and still, some of this stuff gives me the willies."

Kevin Washington can be reached at kevin.washington@baltsun.com.

Web sites for ghost hunters

Beverly Litsinger of Randallstown didn't like the leader of her first ghost hunting expedition, so she decided to do it herself and put up a Web site for her Maryland Ghost & Spirit Association (www.marylandghosts.com).

Litsinger now leads ghost tours and investigations. Her site lists Maryland hauntings by county (Baltimore County has 12 and the city has 28) as well as tips for ghost hunting.

Other ghost hunters (and anti-ghosters) are happy to share their knowledge on the Web. Here are a few:

Ghost Research Society: http://ghostresearch.org

D.C. Metro Area Ghost Watchers: www.dchauntings.com Pennsylvania Ghost Hunters Society: http://home.supernet.- com/~rfisher/pghs.html

Ghosts of Gettysburg books and tours: www.ghostsofgettysburg. com

The Atlantic Paranormal Society: http://the-atlantic- paranormal-society.com

International Ghost Hunters Society (which has standards and protocols for investigations): www.ghostweb.com

Rhine Research Center, a parapsychology institute in Durham, N.C.: www.rhine.org

Less EMF Inc. (for EMF detectors): www.lessemf.com