Hi Sherwood, Thanks for the advice and info. Very helpful.
I was aware of some of the risks of using a hex editor to change program files (and similar files). For a few years back in the early/mid 80's I had to tweak my favorite word processor (XyWrite) so that it would work with a Hyperion computer, whose character table was non-standard. I seem to recall tweaking a modem driver too. (300 baud. Wow! I could read email messages as they scrolled in. Pre-spam days… sigh.) Re image orientation numerical values: How can I find out what numbers are "generally regarded as meaningful"? I would expect any competently written program to handle out-of-range numbers 'gracefully' as long as they occupied the same number of bits. (Graceful = ignore or substitute a default, with or without an error message) I like your 'extended copyright' idea. Would you be willing to share the script you use replace the placeholding X's? I assume you automate the ExifTool??? Looking at ExifTool's instructions and examples is near the top of my "I've gotta learn that!" list (up there with Brahms Op.79, controlling DC motor speeds, and figuring out the network wiring in my house). 🙂 (On Mac, I use A Better Finder Rename to rename imported raw files to Exif date & time, making on-disk file organization by date/time dead simple, but I don't think it gives access to other exif data.) Myron ________________________________ From: Sherwood Botsford <[email protected]> Sent: January 29, 2020 12:16 PM To: dt-user list <[email protected]> Subject: Re: [darktable-user] Semi-OT: setting orientation ✉External message: Use caution. If you are going to experiment with editing raw files, some risk factors: From reading Phil's exif web site, and other stuff I didn't bookmark corruption risk: Safest: 1. Editing standard metadata (Exif, ITPC) replacing a value with one of the same size. Image orientation would be one of these, I think, having a value of 0-3 (but check the range. Suppose it is 0 to3 and you put in 5? Will other software ignore it, only pay attention to the smallest two bits of the number, interpreting it as a 1, go wandering off into a cloud of blue bits and crash?) 2. Editing standard metadata replacing a value with one that is smaller. Some fields are text strings, and so can be padded with blanks, changing the problem to that of problem 1. 3. Editing makernotes data. This is propriatary to the camara maker, and it's format can vary with both model and firmware version. 4. Editing preview images. The big risk here is that the size of the preview will change, and whatever you edit with won't leave the end of the data in the same place, potentially clobbering the front end of the raw data. 5. Editing uncompressed raw data. 6. Editing compressed raw data. Most risky. One of my ideas is to deliberately in my camera put an extended copyright notice such as Copyright S. G. Botsford 2020 -- Image ID Nikon-D7100-S.7614346-XXXX-XXXX-XXXX-XXXX-XXXX Then, with a script read the exif date, and the shutter count, and replace the string of X's with the date and shutter count. This gives a unique ID trackable back to me for the image. I don't know if all cameras write an ITPC core section in the meta data, or if this field is in the maker notes. In all derived files, copy this information to a few other fields. Not all photo editors respect metadata. Your image database tracks this. * You edited a bunch of images with Photoshop, saved under different names. -- you still have a way to connect the .PSD, the resulting TIFF with the original RAW. * Your assistant used a file browser to "organize" your image archive. -- you can reconnect xmp files with masters. * Your database has crashed, taking everything with it. XMP files can be reconnected with masters even if names are in doubt. * You exported a bunch of images. Someone wants a modification that will work better if starting from the original. It doesn't work for all cameras. iPhones don't have a shutter count, nor AFAIK a raw format available to the public. Regards Sherwood On Wed, 29 Jan 2020 at 05:43, Patrick Shanahan <[email protected]<mailto:[email protected]>> wrote: * Myron Gochnauer <[email protected]<mailto:[email protected]>> [01-29-20 03:05]: > Several people suggested trying exiftool… carefully!! (I’ve been burned > often enough to know you only experiment on copies.) > > Anyway, exiftool -a -u -g1 {fname} showed the following results: > > “Orientation : Horizontal (normal)” - - - in exif of NEF landscape format > image file. > > "Orientation : Rotate 270 CW” - - - in exif of RAF portrait format image file. > > I’ll see if I can figure out how to edit those values. (I’m a total newbie > with exiftool.) > > It *does* seem like there is a place for a GUI app, complete with error > checking, for altering exif information. If nothing else, I’m pretty sure > that *everyone* sooner or later produces a bunch of images with last year’s > copyright information, the wrong time, or some other annoying error. A "mantra" of darktable is to not touch in any way the "raw" image. Editing with exiftool or exiv2 both will make changes to the "raw" image file with unknown now or future consequences. You by using darktable have opted to use a photo editor which does not change in any way the "raw" image. Why contradict that by makeing changes with another apt? It is no more work to rotate the images using darktable. And darktable will store the image orientation that you determine within the xmp file and the library. Maintain backups of your library and your raw image files and their accompanying xmp files and your orientation will also be retained. Do what you want with exported images, you have an original now so you can always make another. And a bonus, no need to research exiftool/exiv2 and craft commandline parameters to rotate your images. ps: does your chosen email client not make line wrapping available for you? Maybe time to change. -- (paka)Patrick Shanahan Plainfield, Indiana, USA @ptilopteri http://en.opensuse.org openSUSE Community Member facebook/ptilopteri Photos: http://wahoo.no-ip.org/piwigo paka @ IRCnet freenode ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected]<mailto:darktable-user%[email protected]> ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected] ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected]
