To digitise video is to use a digital videotape to record the information produced by an analogue video, encoding as it goes.

Considerations about digitising
The process of digitising on tape has similarities with making a master, and much of the advice and procedures detailed in the mastering section are well worth looking at in parallel.  Having said that, while it is likely that you will take copies fro m the new digital version and, in a way, treat it as a master, it is important to remember that it is not the original version.

The process also raises the question of whether it's appropriate to digitise your piece of work in the first place.  Is there something about the work that makes a strong connection with its original format?  How would it have been originally shown? If it needs restorative attention, are there any other more appropriate options?  For more in this line of questioning, have a look at the decisions and documentation section within issues to consider.

The preservationist, Jim Linder, make other notes of caution about digitising at the link below

palimpsest.stanford.edu/byauth/lindner/digirecon.html

Much of the information he discusses is contained elsewhere on this site, particularly the warnings about the compression used in digital formats; in this site discussed in the formats section.  The other significant points he makes are that

- Digital is not the perfect solution.

- As with analogue, digital equipment will become obsolete.

- Digital information is carried by a physical object, whether on tape or computer, and is thus still subject to various stresses and strains.

- The digital copy will be different to the analogue original. 

- This original should still be carefully looked after.  You may need its information in the future.

Whilst its good to bear these precautions in mind, because you can copy without degradation, digital tapes are, however, still very useful.

Practicalities
Because analogue tapes produce variable signals it means the actual process of copying the information onto a digital tape can vary too.  There are, however, certain things that you can do to help you get a good digital copy.

It is best to use the earliest version of a piece to digitise from.  As long as it has not deteriorated, this will give a better picture than any subsequent copies.

Clean the analogue tape that you will record from, and use a new digital tape to record onto.  It would be a good idea to document the entire process, noting the procedures and copies/versions that you used.  The potential to read about the biography of a piece or tape could be very helpful for restoration in the future.

Galleries looking to transfer older video material may wish to use a Time-Base Corrector to control the timing of a potentially unstable video.  This kind of processor can correct numerous play back problems but you will probably need to contact a professional facilities house to get access to one.

As the 'formats for preservation' part of the formats section discusses, Digibeta is the best for digitising onto but in its absence, DVCAM is much better mini DV. 

Technological set-up and connections
In addition to the tapes and equipment, the way the information is relayed effects the quality of the information that is being received.  Different types of connecting cables or leads pass the information in different ways.  This largely consists of how the pictorial information is divided up.  In effect, the more divisions there are, the more stable is the signal. 

Composite has only one channel to pass all the information about the picture, and two for the left and right stereo signal channels.    These are sometimes used at home and are often referred to as 'phono' leads.  These should certainly not be used for copying if you want to get a very good picture.

S-video has separate audio connection but has two parts for the picture.  These are referred to as Y and C.  Y stands for luminance, the levels of white and black, and C is the chroma or colour.

Component divides the picture into three parts.  These are technically referred to as Y - R, B - R and Y, with Y again representing the luminance and the others dividing the colour into two channels.  (These codes may be useful for looking at technical diagrams.) 

This combination or separation of information relates to how different formats carry their signal too.  Older video formats, such as VHS and low band U-matic carry a the single composite signal while Betacam SP and Digibeta carry the component signal divided in three.

If you have the facilities, component connections produce the best picture and are recommended for copying and digitising, but also for any other occasion when you want a very good picture.  (For example, if you've spent a lot of money on a very good video projector, you should use the best leads possible.)  This is, however, a best possible scenario that is not always possible to achieve.   The standard DVCAM decks do not even have a component output.  In these instances you should use the s-video connection and not the single composite.

Similar things could be said about sound. To get very good sound, you could use balanced audio connections instead of the basic phono left and right leads, but not all set-ups are appropriately equipped.  Balanced points of connection help to reduce any additional unwanted noise and high frequencies. High quality microphones, as used by musicians, have these.  They have a three-pin connection and a clip.  Again not all decks have this as an available output, most notable here being the standard DVCAM deck.  Essentially, if you're able to record onto Digibeta you should use balanced audio connections but if you're not able to do so, do not worry.

Digital information on computer
Once a piece of analogue work has been recorded onto a digital tape, the new digital information (or anything else 'born digitally') can be stored, manipulated and delivered in a variety of ways. With the appropriate software, it can be played into your computer.

The important thing to remember here is that once on computer, the information is not perfectly preserved forever, despite the temptation to think so.  The information is still being carried by a physical object and thus faces the risk of that object breaking or ceasing to function.  Saved information can also always be lost or suffer corruption too.  It is certainly recommended that you make a digital tape copy of any such work.