When editing RAW photos and attempting to save as PNG, EXIF and IPTC and Metadata are not copied to PNG!
How did you confirm this dysfunction ? How did you test ? Exif, IPTC, and XMP are copied as byte array in internal PNG chunk. All is preserve, and since the first version of digiKam. I'm sure, i implemented this feature myself and patch Exiv2 shared lib to support PNG file format. PNG do not support metadata as Exif, Iptc, or XMP in standard, even if Adobe write some specification about to support XMP in PNG late in PNG format life. Before Adobe and XMP support, Open source as add the capability to support this metadata chunk in PNG. Look ImageMagick for ex. You can convert JPEG with metadata in PNG and convert back to JPEG without to lost these important information. So before to conclude and critic quickly all the work done in DK project, check you words well... Gilles Caulier
Also, you need to be MORE precise : WHICH RAW file format did you use ? There are more than 800 RAW file format supported in digiKam. This is a big puzzle to solve. So, perhaps... with your RAW file format, your metadata extraction to backport in PNG do not work well. If it's the case, do not blame DK team, but ask to your camera maker to not try to re-invent the wheel at each camera model commercialized... In all cases, i tried to load and save a JPEG file with EXIF, Iptc, and Xmp metadata to PNG, and all informations are preserved, as EXPECTED... Gilles Caulier
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