EXPORT - Adobe Photoshop Lightroom 3: Streamlining Your Digital Photography Process - page 256

Derivatives, then, are copies of the original, made for specii c purposes, and with
i le settings based on those purposes .

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A couple of examples:

• You have a native camera raw i le in your catalog that you need to export and
send to a print lab in tif f ormat. h e raw i le is the original, the tif is t he
derivative.

• You have a layered psd i le in your catalog from which you export a jpg i le to
email to your client. h e psd is the original; the jpg is the derivative.

Making i les on disk from virtual copies
Remember that a virtual copy does not exist anywhere on your hard disk. It's just
another instance of the i le within the Lightroom catalog. So if you delete the
original, or your catalog becomes corrupt, etc. and you don't have a backup (shame,
shame), those vcs will be gone along with the work you put into them. So it can ot en
be safest to export new tifs o r dng s from those vcs, in which case you can also back
up those photos as actual i les on disk. (Exporting a vc made from a raw or dng i le
as a new dng is especially clever.)

Don't keep what you don't need
Some derivative i les don't need to be kept around at er you're done using
them for their immediate purpose. For example, I usually don't keep derivative
jpgs, since they're always made to a certain size and for a specii c purpose
and remaking them later, if necessary, doesn't take much ef ort. I don't like
cluttering up my hard drive with i les that will only be used once, so I delete these
derivatives when I'm done with them.

Overwriting the original
Be careful when you export from Lightroom that you don't unintentionally
overwrite your original image. Lightroom will prompt you if it encounters a i le
with an identical name, which we'll look at in a few moments.

PLANNING THE EXPORT
Like other parts of the workl ow, exporting from Lightroom requires some
thinking ahead. Before exporting, determine the requirements for the i les that
will be produced. Be as specii c as you can. Write it out if it helps. Ask yourself:

• How are the i les to be used?

• Do you have a set of specii cations to follow?