As more and more users are making their own DVD's, they are discovering something new. Their home made DVD's, called "one-offs", will not play on their DVD player, even though store bought pre-recorded disks play properly. It is not unusual that a home made DVD may play on some DVD players and not others. Typically, newer DVD players can read these disks more reliably, but not always. The brand isn't such a determining factor either, as two models from the same manufacturer can have different playback capabilities. Sometimes a 40 dollar player works fine, and a 200 dollar player will not read the DVD at all. It can be hit or miss trying to match the player to the most compatible brand of blank disk.
The entire DVD recording and playing process is based on light, just like a camera lens. Get your camera lens a little dirty or covered with dust, and it does not stop working. It still takes pictures, but they may have a slight haze if the lens isn't clean. In a DVD recorder, the cleaner the lens, the better the burn and the more tolerant the playback.
Use a soft cotton swab and a touch of household rubbing alcohol. You want it moist, not soaking wet. Be careful not to press too hard when cleaning. The lenses are cheap plastic and can scratch, creating more of a problem than the dust on the lens. Those scratches can not be cleaned.
Cleaning the laser lens might help somewhat, but it does not change the sensitivity of the laser sensor or the electronics. Newer players are built to be more tolerant of the process because manufacturers know people are burning DVD's on a regular basis. No DVD player manufacturer wants their machine to get a reputation for not playing home made DVD's, so they do all they can to make them work with greater playback tolerance.
If the disk itself becomes scratched, this can reduce the playback efficiency. If the scratch is deep, it can render a portion of a disk unplayable. The disk will usually play part way, then stop and lock up when the laser gets to the part with the scratch. That's an indication of a disk problem more than a player problem. In rare cases, I've seen blank disks with an air bubble or separation between the layers. Don't even bother recording on a disk like this if you see such a problem.
Not all blank DVD disks are created equal. They can vary in quality and color from batch to batch from the same manufacturer. The biggest difference is the color of the recording side of the DVD. It's purple. The color purple was chosen since it's the most efficient compromise between absorption of red laser light for the burning process and laser reflectivity for the playback process. Purple disks reflect between 60 and 75 percent of the laser light, depending on the darkness of the purple. Conventional store bought movies on DVD's are silver, and reflect about 95 percent of the light from the laser in your player. Silver disks are pressed in a factory from a glass master, not burned like in your recorder. You can't burn a silver disk because the silver reflects too much light to absorb the burning energy of the laser. Your recorder has a laser that actually melts tiny pits in the plastic layer of the disk underneath the outer clear layer. The darker the purple, the better the burn. The lighter the purple, the better the playback. Every DVD manufacturer strives to find the best balance between the two. Usually, the lighter color is more compatible in more players.
If lens cleaning and changing disk manufacturers does not help, try to find a player that can read your disk, then copy it onto a new blank from a manufacturer that you know plays well in your machine. Unlike copying tapes, there is no generation loss of quality copying a DVD unless you re-compress the video files, but that's another story. Your best bet is to find a friend or a video duplication company that can make a bit by bit copy on a stand-alone duplicator, not a computer. If that disk still won't play, you need a new DVD player. Bring your DVD to a store and try it on several players until you find one that works reliably, then buy that player.
Rick Bennette
