jhead -te originals/&i *.jpg
From jhead man page:
The "-te file" option from jhead can be used to transplant Exif header from a JPEG (with Exif header) in file into the image that is manipulated. This option is useful if you like to edit the photos but still want the Exif header on your photos. As most photo editing programs will wipe out the Exif header, this option can be used to re-copy them back from original copies after editing the photos.
This option uses a 'relative path', which is useful for doing a batch of photos at a time. For example, if you have a directory full of digital camera photos, before editing them, you could copy them into the subdirectory 'originals'. Then edit them. After editing, you can put the original Exif headers back in to the whole directory of images at a time using the incantation:
jhead -te originals/&i *.jpg
documented on: 2007.06.17
Newsgroups: gmane.comp.video.image-magick.user Date: Sun, 17 Jun 2007
Hi Anthony,
On http://www.imagemagick.org/Usage/photos/, you have a minor underexposure example.
Before going into -sigmoidal-contrast operator, maybe it is a good idea to first discuss convert's built-in -normalize operator that is similar to GIMP's "auto-levels" or "normalize" feature that stretch pixel values from darkest to brightest.
convert minor.jpg -normalize minor.normalized.jpg
FYI, the following comments were taken out from http://www.linux-mag.com/id/2627/
Normalizing high-contrast line art and graphics can be great. But normalized photos may look unreal, and, as was said earlier, may not print well either. The -contrast-stretch operator can limit the "boundaries" of the normalization, but the -levels and/or -sigmoidal-contrast operator can make "smoother" adjustments.
Also, maybe you'd like to through in how IM can also create the three-color histogram out of it:
convert minor.jpg histogram:- | convert - minor.histogram.jpg
Looking at the histogram, I think it may explain what you wrote:
Sigmoidal contrast brightening tends to de-emphasize the red end of the spectrum. You may end up having to select a parameter that results in the most natural flesh tones, rather than the brightness level you really want.
documented on: 2007.06.17
| Also, maybe you'd like to through in how IM can also create the | three-color histogram out of it:
Actually I did not write it. It was contributed. If you like to edit the page, you are welcome to do so, and send me the results.
Photo processing is NOT a strong point of mine.
| Looking at the histogram, I think it may explain what you wrote:
Also see the more low level operator discussions on the 'Color Modifications' page… http://www.imagemagick.org/Usage/colors/
Anthony Thyssen