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Meta What?
Besides the actual photo, digital images also contain
metadata; data about data, including EXIF and IPTC. EXIF is the
information about how the image was captured (shutter speed, lens,
time/date, etc). IPTC is used to enter information to describe what
the image is about (the who, what, when, why, how).
Had the Orphan
Works legislation been passed by the US Congress, IPTC data
may become even more important. More on this later.
EXIF (Exchangeable Image File Format) records a
lot of useful, technical information about how an image is captured.
As mentioned this includes the camera settings such as camera model,
shutter speed, colour temperature, color space, and also includes
when the photo was taken, where it was shot (with a GPS enabled camera),
etc. With the exception of date and time EXIF data is read-only.
Apart from geek appeal why is this stuff useful
to professional photographers? Well, if you use multiple cameras
on a job and want to quickly sequence the images later, most image
browsers allow you to view by date and time captured (fig 1). From
there it's simply a matter of batch renaming using a number sequence.
Some applications use the EXIF to automate post-production.
Noise reduction software for example can detect what camera and
ISO you've used, and use the appropriate settings without needing
intervention. Similarly Photoshop plugins that correct lens distortion
and chromatic aberrations can use EXIF to set default parameters
automatically.
If you suspect your equipment or technique is
at fault it's easy to find all images taken with a particular camera/lens/aperture/color
temperature, etc. With film you would have had to shoot a lot of
film and take careful notes.
Some photographers may not want clients accessing
all this EXIF information. They may not necessarily like others
to know when an image was made, or the time taken between shots,
or even the type of camera used.
Software is available that can strip EXIF data
out. The Adobe Studio Exchange (www.adobe.com/studio)
have a free JavaScript for Photoshop called StripExif that will
remove all metadata including IPTC. To use this in Photoshop CS2
you may need to rename the extension from .js to .jsx.
In the mid-seventies the IPTC (International Press Trade Council)
devised a set of metadata for images that were "wired" to media
organizations to contain information about the subject of the photograph.
IPTC fields were standardised and include Caption, Author, and Copyright.
Other fields were set up to record codes relevant to news organisations
such as, Country codes and Urgency.
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Fig 1. EXIF as displayed in iView MediaPro.
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Using IPTC photographers can store inside their
photos information about copyright, their name and URL, and anything
pertinent to the image. Applications such as Adobe Photoshop and
the latest computer operating systems can display this information
to anyone looking for it (fig 2).
IPTC works sort of like the label we would stick
on 35mm slide mounts. Unfortunately just as with other metadata,
IPTC can be stripped from a photo. Then again, those slide labels
could just as easily be removed.
Since the rise of digital photography
in the nineties people have been using IPTC to store information
not originally intended for particular fields, such as recording
the usage licensed in the Special Instructions field. This prompted
the IPTC update the IPTC fields to better reflect today's requirements.
In 2004 IPTC Core was released. It offers many
more useful fields aimed at areas such as rights management and
specific contact details. Based on XMP it allows users to make custom
IPTC fields and share them as templates in other XMP compliant software.
Currently only Adobe fully supports XMP. Like anything new there
are teething problems.
Most application vendors that have supported
IPTC have done so using the older specifications that stores data
in the Information Resource Block (IRB) based on Information Interchange
Model (IIM). Bringing software up to speed with XMP will take time.
Issues have arisen with the change to XMP. When
one application has written IPTC using IRB into a file and a second
program updates that data using XMP it's possible that two sets
of metadata now exist in the file, IRB and XMP.
Furthermore, older image browsers may not be
able to see the updated XMP information. The question is, which
information is current and which should be ignored? Remember your
clients may not be using the latest software.
Until all mainstream applications use XMP it
may be best to stick to either IRB and IIM, or XMP and IPTC Core.
Essentially this means only caption in Adobe products, or never
caption in Adobe products.
If you caption before Photoshop it will honor
legacy IPTC metadata and copy it to any derivative image. Alternatively
discipline yourself to only use Adobe Bridge or Photoshop for writing
and appending IPTC.
Like any new standard time will eventually sort
this out. When applications can read and write IPTC together it
is often referred to as roundtrip metadata. Asset management software
Extensis Portfolio 8, iView MediaPro 3, and MediaDex can both read
and write XMP, but currently only Portfolio can work with IPTC Core
custom panels.
You can use whichever fields you like. As a minimum
I would suggest:
- Copyright : © 2005
Robert Edwards
- Author : e.g.
Robert Edwards
- Author Title
: Photographer
- Special Instructions
: XYZ Bank, 12 months, worldwide, internet usage only, expires
01/01/2007
- Caption : © 2005
Robert Edwards. www.robert-edwards.com. XYZ Bank, 12 months exclusive,
worldwide usage, expires 01/01/2007
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Fig 2. Adobe Bridge displaying IPTC. Note
it can show both the IIM and IPTC Core fields.
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Fig 3. Photo Mechanic maintains IPTC standards and allows you to
append or replace metadata.
Notice the caption duplicates the information. Some applications
(and people) only read the IPTC caption so it may be worth repeating any
important information there. Bare in mind many businesses will write their
own caption so anticipate anything you write here to be over-written.
It's still worthwhile filling in the other fields.
Most applications that write IPTC allow you to save data
entered into the various fields as templates (Fig 3).
This saves time and prevents mistakes. Your first template should be one
that has all your copyright and contact details. Then it's a simple matter
of adding this metadata as a batch to any number of images. Ignoring Caption
and Special Instructions, Figure 3 demonstrates what a basic copyright
template for Photo Mechanic can include. IPTC Core also allows you to
enter your telephone number, address, and email, and more.
If you supply photo libraries check how they use IPTC.
Most have strict guidelines and a few offer custom templates. It's important
to enter the information correctly so potential customers searching for
images find your photos. These taxonomies are essential for librarians,
however as a photographer you don't need to know the underlying science.
Using a limited set of words, or a controlled vocabulary to describe images
ensures standardisation. What you call a landscape to others may be a
mountain, hillside, country, farm ...
The aforementioned Orphan
Works US legislation now makes embedding IPTC essential for all professional
photographers. Had this bill passed it required users of your images to
only make a "good faith, reasonably diligent search" to locate
you - the legal copyright owner. If they can't locate you then they are
essentially free to use your work.
If you discover their use and the copyright infringer ceases
using your images they are not required to pay you a cent. Even if they
have profited from using your images before you notified them! While Orphan
Works has been withdrawn don't underestimate the power of this bill. Orphan
Works could be presented to Congress again in 2007 under a different name.
If passed its effect would spread beyond the USA.
Many photographers organisations including the ASMP
are fighting the Orphan Works bill. So start writing IPTC information
into your files so people know you own the copyright and how they may
contact you.
Some information can be added automatically (Fig 4). For example most applications
that transfer your files from the CF card to the hard drive can write the
general information such as copyright, author and author title at the same
time. Many applications can batch caption so you need not open one image
at a time.
Fig 4. Photo Mechanic is shown here using the
ingest feature. Once set it can automatically transfer files, back
up, rename and enter IPTC information.
Some applications when appending IPTC delete any previous information.
This is especially true with captions. Few apps can be set to add more
info to a caption.
For example, say you photographed Nicole Kidman. On downloading the images
to your computer it automatically adds all the relevant copyright and
contact details, plus you tell it to also include in the caption; "Nicole
Kidman".
Later you want to append the Caption on some images to read "Nicole Kidman
with her children, Isabella and Conor". The easiest way is to select those
images and add " with her children, Isabella and Conor". Some applications
may not append the "Nicole Kidman" part and only write " with her children,
Isabella and Conor".
Many applications including Photoshop don't like carriage returns (line
returns) in IPTC. So avoid using the return key when entering captions.
A more problematic issue arises for photographers using RAW files. The
benefit captioning a RAW file is all conversions made from it will parse
the IPTC data along, saving you having to caption the same photos multiple
times.
With the exception of DNG, all RAW files are proprietary to their camera
manufacturers who don't document where to store IPTC. If it's written
to the wrong area of a RAW file it may irreversibly damage the file. Apple
users are reasonably "safe" because the Mac file system allows you to
safely store data like IPTC into the resource fork. While PC users can
read IPTC written to the Mac resource fork it can accidentally be stripped
simply by moving or emailing the image.
Many applications will write metadata to so-called sidecar files. These
files sit alongside your image files and often have the same filename
but different extension, eg. 040506_005.cr2 is the image and 040506_005.xmp
is the sidecar. When you write IPTC information it's stored in this sidecar
leaving your image untouched.
This is good because you're not modifying undocumented files like RAW
images. The downside is sidecar files are easily orphaned losing all the
important information you invested time in entering. Some applications
that use sidecar files to store IPTC for RAW files are Adobe Photoshop,
PhaseOne C1DSLR, and Bibble.
Unfortunately none of their sidecar files compatible with one another.
It also requires you to use the application that wrote the sidecar file
to move, rename and delete images otherwise you risk losing them. Again
it is best to enter IPTC at the beginning into RAW files, or at the end
into the converted TIFF or JPEG files that are documented formats.
Digital asset management (DAM) applications can often sync metadata between
files with the same name but different extension. Once you've captioned
your converted images they will copy the metadata to the RAW file or vice
versa. This information is stored in DAM database and doesn't modify the
RAW file, unless you choose to do so.
Invest a little time to trial applications and procedures on disposable
images before adopting metadata into your work environment. Experiment
and decide which IPTC method best suits your workflow.
The first decision should be whether to write metadata into RAW files.
This will determine when and how to write IPTC. Thoroughly test your IPTC
through the whole digital workflow from download, RAW conversion, to archiving.
In particular test any application you intend using to write metadata
into RAW file formats.
Once established and adhered to the goal of writing metadata is save
time and increase sales in the long term by making images easy to find,
and protecting your rights.
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