Thursday, March 22, 2012

Indian Coral Bean Tree in California

At the Oakland Zoo.  These trees are important calendric markers throughout the Pacific.  I do not know what species this tree is, in the Oakland Zoo Parking Log.  See the photo in the header of this blog, from Saipan, Northern Mariana Islands.


Saving comments to the exif file of jpeg images

I am using GNU/Linux.  I use several image viewing, organizing, and editing tools.   Having spent hours and hours organizing my photos in one utility, for example, Gthumb, a fairly straightforward tool, with comments, these comments are stored in an invisible dot file, accessible only from that application.  For years, I've wondered "How can I save these comments in a permanent manner?"

I have just made a little progress on this issue.  So I will post a BRIEF description of what I have found.  There is more to learn, and maybe I can get around to this another time.

There are at least two metadata standards:

  1. Exif:

  2. IPTC: the International Press Telecommunications Council standard.

Tags saved with Gwenview is only possible within Gentoo GNU/Linux when it has been compiled with certain USE flags.  I won't get into this now.   Also, I don't know how to go about doing this, yet, with Ubuntu or other distributions.

I finally experimented with tags today.  They were apparently saved as IPTC tags, not visible in the utility "exiftags" which I think is hardwired for a standard set of tags, to allow reading and maybe manipulation of exif tags of a few types in image files, maybe to change a date, I don't know.

Another application is "jhead."   With jhead, I was able to add an exif tag, "Comment", with my own comments.  This tag is readable in jhead, at least.  And jhead also saw the IPTC tag I stored in the same image using Gwenview.

Other programs I am using are

  1. shotwell -- good for importing files into a date tree from an SDCard

  2. Picasa -- good at organizing, but has those sad volatile meta data.  Unfortunately Google, written originally in GNU/Linux, has not provided native GNU/Linux ports of this.  It runs on top of Wine.   Not completely acceptable yet.  Maybe good for uploading, if I get into that.

  3. gthumb

  4. digikam -- I will experiment, but previously had some issues.  First, will it import to the same tree as shotwell?  I saw a comment on the Inet that Digikam uses IPTC metadata.  Interesting.

  5. gwenview (KDE4) -- does a lot, and because it's local (on the HDD) and is native, it is pretty attractive.  It's gymnastics with tags are so far useful.   Saves tags in IPTC format.

  6. some gnome tools?

Here are some commands with jhead:

  1. to add a comment:: jhead -ce <path to file>

  2. to read the metadata (exif and IPTC):: jhead <filename>

  3. to see other options:: jhead -h

Here are the comments from an image I worked on today:
  ~/WB/org $  jhead  ~/Pictures/2012/03/22/img_0592.jpg
File name    : /home/deckert/Pictures/2012/03/22/img_0592.jpg
File size    : 130820 bytes
File date    : 2012:03:22 08:38:06
Camera make  : Canon
Camera model : Canon PowerShot SD1100 IS
Date/Time    : 2012:03:22 08:38:06
Resolution   : 2048 x 1536
Flash used   : Yes (manual, red eye reduction mode)
Focal length : 18.6mm  (35mm equivalent: 117mm)
CCD width    : 5.72mm
Exposure time: 0.017 s  (1/60)
Aperture     : f/14.0
Focus dist.  : 0.45m
ISO equiv.   : 100
Whitebalance : Manual
Metering Mode: pattern
Comment      : Tripod used, Crab Cove
Comment      :

======= IPTC data: =======
Keywords      : tripod


A more complete readout of standard exif tags is found with "exiftags".  No custom or comment exif tags were seen.
~/WB/org $ exiftags ~/Pictures/2012/03/22/img_0592.jpg
Camera-Specific Properties:

Camera Model: Canon PowerShot SD1100 IS
Equipment Make: Canon
Camera Software: Picasa 3.0
Maximum Lens Aperture: f/4.9
Sensing Method: One-Chip Color Area
Lens Size: 6.20 - 18.60 mm
Firmware Version: Firmware Version 1.00
Owner Name: Alan and Fe

Image-Specific Properties:

Image Orientation: Top, Left-Hand
Horizontal Resolution: 180 dpi
Vertical Resolution: 180 dpi
Image Created: 2012:03:22 08:38:06
Exposure Time: 1/60 sec
F-Number: f/14.0
ISO Speed Rating: 100
Lens Aperture: f/14.0
Exposure Bias: 0 EV
Flash: Flash, Compulsory, Red-Eye Reduce
Focal Length: 18.60 mm
Color Space Information: sRGB
Image Width: 2048
Image Height: 1536
Rendering: Normal
Exposure Mode: Auto
Scene Capture Type: Standard
Unique Image ID: 5b5bfc656e8e1824c2814e2936491976
Focus Type: Close-Up (Macro Mode)
Metering Mode: Evaluative
Sharpness: Normal
Saturation: Normal
Contrast: Normal
Shooting Mode: Manual
Image Size: Unknown
Focus Mode: Single
Drive Mode: Single
Flash Mode: Red-Eye Reduction (On)
Compression Setting: Normal
Macro Mode: Macro
Subject Distance: 0.450 m
White Balance: Custom
Exposure Compensation: 3
Sensor ISO Speed: 160
Image Number: 100-0592