Linux Format forums

[lucast]

Dear everyone,
I have returned from my month-long honeymoon a few months ago, with thousands of photos to share with family and friends.
My camera is far from perfect so I tweak the photos I email to friends by adding brightness and contrast, and adding a bit of saturation out of hue, lightness and saturation.

I read the LXF135 Sept10 ImageMagick tutorial and it seemed like the answer to my prayers, since with mogrify, I could edit thousands of photos from my trip simply by using command line functionality.

The problem is that I just want to add 6 units (i don't know whether is percentage or anything else) of contrast to each photo (In Gimp, that would be Colours => Brightness-Contrast Option) and 6 units (i don't know whether is percentage or anything else) of Saturation out of Hue-Lightness-Saturation (In Gimp, that would be Colours => Hue-Saturation... Option).


The issue is that when looking at ImageMagick, I could not find an option to add contrast by the units I desired, and the option to add saturation is compared to the GIMP option of Colours => Colourise which yields a totally unintended result.

Would any kind soul out there know how to batch edit photos in the areas I have mentioned only?
Any google search points me back to ImageMagick and initial predicament.

Image editing is certainly not my area of expertise and solving this problem would save me hours of work.

Thanks in advance,
_________________
Mr T

[johnhudson]

Is the answer to find out what your 'units' are and express them as a percentage of the whole range to which they apply; then double that figure and apply that change either positively or negatively in ImageMagick?

http://www.imagemagick.org/script/command-line-options.php#brightness-contrast

[nicephotog]

Just aside note(extra inf) , i have always found using the "white slider"(represent using all three RGB at the one time alike Gamma(gamma has also a balance calculation)) in Gimp is more cohesively - effective overall for brightening than using the brightness switch. Using all three RGB as white may result in requirement to commit some minor colour re-adjustment for colour balance.

I recently built a photo colour balancer(freeware), but sadly here neither use GimpPERL or ImageMagik.
http://www.nicephotog-jsp.net/Sidewinder.html

[sledgehammer]

Its been a long while since I used it, but have you tried Phatch?

[lucast]

Thanks johnhudson,
I have tried that option, convert -verbose -brightness-contrast 10 holidayPhoto.jpg but I get the following:

unrecognized option `-brightness-contrast' @ convert.c/ConvertImageCommand/802.

I have also tried -contrast option only but it doesn't give the option to even specify percentage.
As for saturation, i still need to figure it out.
Thanks, everyone for your replies.
I haven't been able to reply straight away but it is much appreciated, nonetheless.
I'll try the other solutions.
Cheers,
_________________
Mr T

[lucast]

Hi Sledgehammer,
Thanks for recommending Phatch, it is exactly what I was looking for.
So easy to use, great and intuitive GUI as well.
Cheers,
_________________
Mr T