Image Enhancement

Table of Contents

Revive dark photos
Revive dark photos — Conclusion
Revive dark photos — Conclusion
Revive dark photos — Conclusion

Revive dark photos

Newsgroups: gmane.linux.debian.user
Date: 2007-01-22

I remember that I revived some dark photos to normal look by simply choosing certain gimp menus. Now I want to do it again, but couldn't find the menu entry any more.

So I went ahead googling the answer, and it seems Normalize, Contrast Auto-stretch and Auto-stretch HSV are three ways of doing it. But I believe I've been to every corner of gimp menu, but didn't find a single clue where those options could be. E.g., Contrast Autostretch should be at (Filters -> Map -> Contrast Autostretch), but it's not there, in my gimp at least.

Revive dark photos

> I remember that I revived some dark photos to normal look by simply
> choosing certain gimp menus. Now I want to do it again, but couldn't
> find the menu entry any more.

As far as I think I know, in many photo editing programs, including Gimp, it usually goes like this:

Tools > Colour tools > Levels...
Select Channel: Red; click 'Auto'
Select Channel: Green; click 'Auto'
Select Channel: Blue; click 'Auto'
Select Channel: Value; click 'Auto'

That should do it in most cases. For grayscale photos, skip the colours.

For more 'difficult' cases, try to adjust the 'Input Levels' and 'Output Levels' in this same dialog, and/or try Tools > Colour Tools > Curves…, e.g. to sharpen the contrast in the dark areas.

Sjoerd Hiemstra

Revive dark photos — Conclusion

Date: 2007-01-23

> I remember that I revived some dark photos to normal look by simply
> choosing certain gimp menus. Now I want to do it again, but couldn't find
> the menu entry any more.

thanks everyone for the respond.

The retinex http://docs.gimp.org/en/plug-in-retinex.html looks very promising, but I found that it is not that automatic — The default does not give optimal result, and I didn't seem to be able to find a good parameter combination.

Sjoerd Hiemstra's suggestion, http://article.gmane.org/gmane.linux.debian.user/270822 is the most comprehensive. I found it has covered all the cases for my dark photos. thanks Sjoerd.

cheers

documented on: 2007.01.22

Revive dark photos — Conclusion

> Sjoerd Hiemstra's suggestion,
> http://article.gmane.org/gmane.linux.debian.user/270822[]
> is the most comprehensive. I found it has covered all the cases
> for my dark photos. thanks Sjoerd.

One of my case is in door shooting, with very big and bright window background, so the front view is pretty dark.

I just found that, if you want to get much complicated than above, there is a tutorial that shows how to blend two different exposures of the same scene to get the best parts of both images.

http://www.gimp.org/tutorials/Blending_Exposures/

documented on: 2007.01.23

Revive dark photos — Conclusion

> I remember that I revived some dark photos to normal look by simply
> choosing certain gimp menus.

Found it now:

Layer -> Colors -> Auto -> White Balance/Normalize/Stretch Contrast, etc.

documented on: 2007-10-23