Hold it right there. Get a pair of scissors. Save this column. You'll need it someday, believe me.

The single most-asked video question I hear (other than "How often should I clean my VCR?") concerns playing of foreign videotapes on domestic VCRs. Every so often I restate the short answer: You can't play them.But there is a longer, more detailed answer. You can play them back with the proper equipment. Because so many people seem to have friends and family abroad, and would like to play "videograms" from them, I'll summarize the options.

The reason you can't play a foreign videotape on a VCR here is that TV equipment in different countries conforms to different broadcast standards. In the United States, we use the NTSC system. The letters stand for National Television System Committee, the group that devised the specifications.

There are two other major broadcast systems, PAL (Phase Alternation by Line) and SECAM (the French acronym for Color Sequence by Memory). PAL is used in most Western European and Asian countries, including Britain, Spain, Germany and China. SECAM is used in France, the Soviet Union and the Mideast.

NTSC is also used by Japan and about half of South America, though Brazil and Argentina use PAL.

Until recently, tapes from non-NTSC countries had to undergo standards conversion to be played here. Conversion is a costly process, starting at several hundreds of dollars, and is not generally an option for the consumer. Clients of conversion studios tend to be video producers, broadcasters and other businesses.

"International" VCRs do exist, but are rare in this country. They are marketed primarily in places that are in receiving range of different standards, such as Eastern Europe and the Mideast.

These VCRs allow playback of any videotape on the native TV equipment. Sometimes in the process, the playback picture suffers from degraded resolution and loss of color.

For U.S. consumers, I'm aware of two equipment options. Neither is cheap, but if you want to swap tapes with friends overseas, the multistandard VCRs offered by Instant Replay and Panasonic are quick and simple solutions.

Although Panasonic is an international giant, let's give entrepreneurship its due and first discuss the Image Translators made by Instant Replay, a small company in Coconut Grove, Fla. There, for more than 10 years, president Charles Azar has been buying VCRs from Matsushita (Panasonic's parent) and customizing them into units that can play back foreign tapes on U.S. TV sets, though they can reproduce SECAM in black-and-white only.

They also are full-featured VCRs, able to play ordinary NTSC tapes and record off the air. Depending on the options you chose (Super VHS, four-head, hi-fi) the various units range from $995 to $2,000.

Late last year, Panasonic finally brought out its own "universal VCR," the AG-W1, which has a list price of $2,500. It too will play back any standard of tape on a U.S. TV set - or any TV set, for that matter - in color.

The AG-W1 can record in any of the three standards, so that you could send a tape to a friend who uses PAL or SECAM. But - and a big "but" it is - it lacks a built-in tuner. That means you must bring in the signal from a second VCR or from a TV set's output if you intend to record anything off the air.

Instant Replay units do have the benefit of a built-in tuner. But the current models, soon to become outmoded, have certain limitations too. They're unable to adjust for something called frame rate. An NTSC broadcast has a field frequency of 60 Hertz and displays 30 frames a second. Both PAL and SECAM have a field frequency of 50 Hertz and display 25 frames per second.

Although the current Image Translator converts PAL and SECAM so they can be played on U.S. TVs, the result is a "modified" NTSC that causes the picture on some sets to roll vertically. It is not a true 30-frame-per-second picture, and some TVs, especially newer ones that lack vertical hold controls, are intolerant of the difference.

Further, this modified NTSC cannot be recorded, even when it can be viewed without trouble.

Beginning next month, however, Instant Replay is revamping its entire line to incorporate a "50/60 digital frame standards converter," which it says is the first on the market for the consumer. Azar promises the 50/60 products overcome the frame-rate problem and allow for the converted NTSC output to be recorded. In other words, the user can make an NTSC copy of a PAL or SECAM tape.

The 50/60 models will replace the earlier Image Translators. For anyone who owns the older units, Instant Replay is offering to retrofit the units with a 50/60 module at a cost of about $500.

- WHERE TO GET MACHINES: Panasonic's AG-W1 is intended primarily for the professional market, so chances are you will not find it in the usual electronics stores. For information on locating the machine in your area, write to Panasonic Industrial Video, 50 Meadowlands Parkway, Secaucus, NJ 07094. For information on Instant Replay's VCRs, write to the company at 2601 S. Bayshore Dr., Suite 1050, Coconut Grove, FL 33133.VIDEO QUESTION

Q: Just what does the VCR tracking dial or button do to clear out the snow from the image?

A: The video signals on a tape are laid down in "tracks." During playback, if the video heads are not aligned properly with the tracks, the result is "snow" or "noise" from mistracking. The tracking dial "tunes in" the VCR to the control pulses that guide the heads along the tracks properly. By the way, many new VCRs have no tracking button - the function is automatic. - Andy Wickstrom (Knight-Ridder)