digiKam PNG workflow...
PNG is my preferred format for archival storage of photographs. It is lossless and more compact than TIFF and TIFF-LZV, more simple to use than TIFF/RAW files, and it's GPL file format...
PNG format can embeded text metadata. Image Magick using this way to save ICC profile from JPEG files when its converted to PNG. The ICC profile is saved like a RAW Bytes Array.
There is no standard for embedding metadata like Exif/IPTC in PNG image files, but i want improved PNG file format support in digiKam, especially about metadata.
My plans are simple:
- Define new digiKam PNG metadata tags names. I think that ExifTools have already define anyone. I will trying to stay homogenous.
- In Camera interface : add a new option to convert on the fly JPEG and RAW files to PNG . Exif from RAW file can be get from THM (JPEG thumbnail) file provides by camera. Put automaticly all JPEG metadata to dedicaced PNG metadata tags.
- In Image editor, When a JPEG file is loaded, and when user export the image to a PNG, doing the same think.
- In Exif viewer, when a PNG file is used, check if JPEG metadata exists and parsing it using libkexif and displaying the results.
All this features can be done to Digikam::DImg::ImageLoader API
How about a djvu workflow ?
The only benefit I see to png is that it's lossless (which in some cases might be important, I agree). But for people who are willing to use a lossy compression algorithm, djvu is much much better than jpg. It's a pity that there isn't a good workflow for it either. So while as you are thinking of something for png, don't forget djvu :-) (No idea whether there are placeholders for metadata, though...)
Good idea!
I think that's a great idea - I feel the same about PNG: It's a great format, but it really is lacking the possibility to store EXIF data in a somewhat standardized way. That's the main thing that keeps me from storing all my pictures in PNG.
I'm also hesitant to make intensive use of the digikam tagging features because they are stored in a separate database rather than being part of the picture. If I ever switch to another application, all the tags are useless. Including EXIF-data in PNG would solve that.
So, go ahead :-)
Thanks!
NilS