PNG metadata

[billseymour]

I've just noticed that after adding metadata to PNG files in iView, and Sync-annotating back to the file:

Applications using these PNG's do not show ANY metadata in the PNG file. I opened these annotated PNG's in Photoshop CS3 and Fireworks CS4- the 'File Info' for both applications is completely blank- none of the metadata I entered (and annotated back to the image file) shows up.

Anyone else encountered this? Is this a peculiarity of iView? Is this not an issue in EM (or iDimager, for that matter)? Does entering metadata to PNG files in another app, like Bridge, 'take' properly so that metadata is retained?

This is very confusing. In the iView catalog, all the metadata for PNG's is present (but I'm guessing this is metadata in the catalog itself; my question relates to using a copy of a PNG image which I thought I'd properly added metadata to).

Thanks for any insight. (Also posting this in EM area).
--Bill

[peterkrogh]

Bill,
I seem to remember something about PNGs not holding metadata, but I'm tired and jet-lagged and might be mis-remembering.

iView lets you create metadata for files that don't support embedding (like lots of movie files) .  It can be used in the catalog environment, but not outside.
Peter

[Dierk]

Eventually it is very simple: PNGs can have metadata but there is no standard on how to. Thus every program does it differently if at all.

I would have like to recommend XMP in this case. Sadly this is even more problematic than using PNGs [in]capabilities of data chunks since not many programs make use of XMP; the only coming to mind consistently and consequently using XMP is IDimager. Haven't tried it for metadatasing PNGs. Even if it works well, chances are IDI is the only application these are visible to. Not to mention the troublesome XMP support in MediaPro [non-existent] and it's successor [better but].

With Adobe, it seems, only Bridge will work half-way decent with PNGs in regard to metadata*.