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Metadata Mutterings
As digital photography begins to mature as a medium, metadata that can be transferred easily and reliably from person to person and application to application becomes increasingly important. Most photographers these days have heard of the ‘IPTC’ and ‘XMP’ standards...
In the process of working on an XMP importer for Aperture I’ve had to deal with some of these standards ‘down on the coal face’.
IPTC (the International Press Telecommunications Council) is the primary body setting standards for metadata in visual media, usually photography. One of those standards is IPTC IIMv4 which Aperture generally supports very well. However, IIMv4 was largely replaced by the newer IPTC Core schema for Adobe’s XMP metadata format back in 2004-5. To some extent you can think of IPTC Core as an expansion on the older IIMv4 standard as the main implication for photographers is the addition of a series of new tags such as contact details for the photographer.
Those extra tags include some pretty important information, some of which is required by various agencies:
Content Creator Info: City
Content Creator Info: Country
Content Creator Info: Address
Content Creator Info: Postal Code
Content Creator Info: State/province
Content Creator Info: Contact Email(s)
Content Creator Info: Contact Phone(s)
Content Creator Info: Contact Web URL(S)
Country Code
Intellectual Genre
Location
Rights Usage Terms
Subject Code
IPTC Scene
Aperture hasn’t quite caught up with those changes...
Side-note: ‘XMP’ refers to a couple of different things - there are XMP sidecar files which are a form of XML files, sitting beside the image file and containing the metadata. Then there is XMP as a format for adding metadata to image files, including the ‘new’ additional tags. XMP as a metadata format could more correctly be thought of a a standard for setting up standards - a typical XMP dataset would include tags from the IPTC Core standard, Dublin Core standard, EXIF (usually split between a whole series of standards such as XMP TIFF), older IPTC tags and application-specific data such as Adobe Camera Raw settings.
Aperture can save out XMP files if you export Master files, but it can’t read in XMP sidecar files, and in any case it doesn’t support the new tags that IPTC Core added.
The practical result is that applications that use the newer IPTC Core standard (Photoshop/Bridge, Photo Mechanic, LightRoom, Expressions Media etc.) can add important information to images that isn’t seen by Aperture. In addition, as Aperture only reads metadata that has been embedded in the image file rather than in XMP sidecar files, it can be very tricky for people to move metadata between applications.
We’re currently in a situation where it’s substantially easier for someone to migrate from Aperture to LightRoom (due to ‘export with XMP sidecars’) than it is to go the other way.
So my current plan for an XMP importer is to add a series of custom tags corresponding to the missing IPTC Core tags and copy the information into these. They will then be fully visible and searchable in Aperture, addable to books and web pages etc. Unfortunately exports will also need to be done via the helper app so that the information can be embedded properly into the exported file or an XMP sidecar file. Or even a sidecar file next to the original Master file.
It’s not a particularly pretty solution, but it should do the job. Well, apart from people using export plug-ins. :-(
Now, some of you may have spotted the bit about Aperture exporting XMP files as an option when exporting Masters. It does, but of course it doesn’t export custom tags, and some of the mapping to IPTC Core tags is simply wrong - for instance Aperture’s IPTC Contact tag is mapped to a ContentCreatorInfo tag. Which isn’t a valid IPTC IIMv4 or Core tag, rather it’s a whole class of Core tags.
Similarly, the IPTC Object Attribute Reference tag in Aperture is mapped to the new Intellectual Genre tag in the XMP file, even though they cover different purposes - from the IPTC documentation, the Object Attribute Reference tag is used when describing the subject of the photo, while the Intellectual Genre tag covers the end use of the news article - feature, summary, wrap-up etc.
At this point in the research I felt the need to go and do something else for awhile...
If the poor support for IPTC Core and XMP files affects you, please go to the Aperture Feedback page and let the Aperture team know about it.
Ian
Comments (10)
Not that it's much out of those tags, but the Country Code one is supported in Aperture. It's been there since I started with 1.5
True, I forgot about Country Code. It's about the only one, though.
Ian, I totally agree with you and thank you for raising this important subject. I've only just become aware of IPTC Core but I did scratch my head when I noticed that Aperture's IPTC fields didn't match other programs. Things like rights usage terms and the address field weren't being picked up when I migrated images I'd processed in LR or other programs. You'd think Apple would want to make it easy to migrate to Aperture. This and the inability to save these into the DNG file is one of my main gripes about Aperture and I have passed it on. I'd also like to be able to store adjustments into the DNG as well (LR can do this). Apart from these issues, I think Aperture 2 is fantastic and I now use it in preference to LR.
It's actually the functionality at this mundane level that can make a program complete.
It drives me nuts that Aperture doesn't properly support the latest (latest, mind you, as of 2005) IPTC schema. Please update this Apple. Please! Oh, and I noted the same thing you did, Ian, that the current mappings for IPTC within Aperture aren't all correct. There are several actually that either don't map or map incorrectly. Frustrating.
Aaron - out of curiosity, what advantage do you see to saving the adjustment settings into individual DNGs over exporting Projects?
Ian - can you tell me the other fields that don't map?
Ian
Nevermind... I re-read your Post and see that you already mentioned what I had discovered. I just sent you a message via your website.
Ian
It does appear that the Aperture team has dropped the ball when it downs to some of the small professional details.
You also have to use the book program to create picture packages and that won't let you use color profiles when printing. They are so close on this app in so many ways but it's the details that forces to jump pack into Photoshop.
The advantage I see of having adjustment settings saved into individual DNGs is that this work is then carried around with the file. This is probably more of an advantage with a file adjusted in LR because the raw engine is the same as Photoshop which can then convert it to a jpg or tiff. Also, you can save a preview inside the file that can be recognised by third party services and programs like Photoshelter - this means when that file is displayed on my website it looks how I want it to. I have spoken to Photoshelter about the possibility of recognising adjustment changes to a DNG file and applying those adjustments when outputting a jpg or tiff. They realise this is important and they're working on it. But no timeframe yet.
Incidentally, I've noticed that when I import referenced DNG files into Aperture that have been adjusted in LR, when the file is loading it shows the jpg preview with LR changes, including crops. When it has fully loaded it reverts to the unadjusted raw file. So Aperture is viewing the embedded preview at some level.
I can see why Aperture doesn't go there - if I make an adjustment to a file in Aperture that has already been adjusted in LR, things could get messy if you were saving instructions into the file from both programs. Maybe a way around it is to have sets of instructions from each program visible in some way and then have the ability to choose between then. That way you could have a single file interpreted in different raw converters. This would be handy for people who have done a lot of legacy work in other programs - I'm not criticising Aperture's raw conversion, I think it is superb.
Aperture prides itself on not touching the raw data but any adjustments to a raw file can be undone - they're instructions, they're not destructive changes. I consider (and I may be alone in this) the option to be able to store these instructions inside the file important, instead of only being part of the library or a whole project. If someone picks up my DNG file in a hundred years (or tomorrow), I want them to have some idea how I would have interpreted it. It seems that having those instructions somewhere else where it can get separated from the file reduces this ability. This is especially important with IPTC. So I don't know why they don't have this option. I didn't use Aperture in its earlier versions but I do vaguely remember there was quite some fuss over how you had to store everything in the Aperture library. Aperture changed this and gave people other options. That's all I'm asking for - options.
Craig, I haven't used the book layout feature yet but not having the ability to use colour profiles would definitely hold that feature back.
Sorry for the long screed off-topic - one more thing, does IPTC Core recognise star ratings from other programs?
re adjustment data in DNGs, this offers the possibility of exchanging some adjustments between Aperture and other programs (both ways). While we'll never be able to figure out how to copy over every single adjustment, some (eg b&w treatment, even WB) might be. We also have portability without dependence on whatever program or OS you may be using as the xmp data in the DNG is readable elsewhere. There's also the long term archival issue - if you can't get your work out of a program when you want to leave it (one day you always do), is it worth putting it in?
This is very critical and something I've been reviewing lately as well. This is all the more important with the probable passage of the orphan works bill. Those of us that rely on sales of images posted on the web as a part of our income really need the ability to tag our images with every bit of contact information we can. I've already submitted feedback to Apple and have contacted everyone I know that may have some influence.