This is a blog about the projects or other things that I am currently working on.  With a little luck you will find some useful information here.  Enjoy!

Improve your Raw photos with UFRaw and Gimp

posted Jul 25, 2010 11:12 AM by Andrés Arenas Vélez   [ updated Aug 10, 2010 1:59 PM ]

My Canon EOS takes very good photos, but as an amateur photographer I not always take the best pictures at the first shot.  Specially problematic is getting the right exposure on every shot, so that is why I prefer to save my photos in Raw format for later processing and retouching.

I am going to describe the basic work flow I use to get the most of my raw photos using two great tools UFRaw + GIMP.

Both tools are available for Windows and Linux.  Since my base distro is Fedora, this is how you can get them both from the standard repositories using yum as root:

yum -y install gimp ufraw ufraw-gimp

Those are the minimum packages you will require, and yum will install all the dependency packages required.  I would recommend installing the help files and the extra tools.

yum -y install gimp-help gimp-help-browser gimp-data-extras gimpfx-foundry

Now let's start loading the photo with UFRaw.  Locate the raw image and right click on it selecting Open with UFRaw.

UFRaw will let you adjust a lot of parameters on your photograph before exporting it to Gimp, but we will focus here in the exposure.  The original exposure is 0.00.  Click on the gears icon and the exposure will be auto-corrected to average the tones on your photo.




Check the Live Histogram, now is normalized.  UFRaw chose -0.28 as the average exposure value.

This is going to be the base exposure for the final photo.  I will generate 3 photos from here, one underexposed, one neutral and one overexposed.
 
Photo              Exposure
Background         -0.28
Underexposed (D)   -2.28 (Background - 2 )
Overexposed  (L)    1.72 (Background + 2 )

To export the photo to Gimp, set the desire exposure and click on the Gimp Icon on the bottom-right corner.  Gimp will open a new window with the photo, preserving all the Exif information of the original.

Repeat the procedure to obtain the three required photos in Gimp.



Now, we want the three photos as layers to work on them as one.  Pick the Underexposed (Dark) photo and go to the Edit menu, then  Copy Visible.  Now go to the Standard exposed picture and select on the Edit menu, Paste as > New Layer.  Repeat the procedure with the Overexposed (Light) photo and finally close them as they are not needed any more.  You should have them all on the same window as layers like this:


I renamed the layers, and this is the order I want them to be.

Now, let's create a layer mask on the Light Layer.  Right click on the layer name and select Add Layer Mask.


Select Grayscale copy of the layer and be sure the Invert mask selector is checked.
Repeat the operation with the Dark Layer, but DO NOT invert the mask.

Now, with both layers with their masks, let's Blur the masks to improve the result.  Select the Light mask and go to the Filters menu / Blur / Gaussian blur...


I usually select around 15-20 on the Blur Radius.  Apply the blur also to the Dark Mask Layer.

Finally, for better results, select the opacity of the Light layer.  I Usually select between 50-70 depending on the picture.


At this point you can save the image using Gimp's xcf extension to preserve the layers and make corrections in the future. 

To export the picture to your preferred format, first merge the layers, right-clicking on any layer and selecting Flatten image.

To go one step further I rotated the image a little using the rotating tool and crop to get the best picture possible.   Let's compare the original with the final version.


You can see the improvement on the dark areas (on the stairs) and the light areas (on the roof) and the mid-tone shadows (on the chairs).

Shooting Raw photos increase the chances to obtain good photos in the end, and with tools like these and a little patience you will obtain great results.



KeePassX + DropBox + PortableApps = Safe Passwords

posted Jul 16, 2010 12:50 PM by Andrés Arenas Vélez   [ updated Jul 23, 2010 7:13 PM ]

Creating useful passwords is a hard task.  To make them secure they should be long and complex enough to support guessing, dictionary or other forms of brute force attacks. On the other hand, long or too cryptic passwords are difficult to remember, so most people end writing them down, or using the same simple password for everything.

Another issue is user names, with every website and service using different user names they can also become very difficult to track.

To solve this in a safe way there is a great Linux application called KeePassX (see KeePass for other platforms).


keepassx-screenshot

KeePassX use a database to store your user names and passwords in a single file.  That file is encrypted with a Master Password, which will be the only password you will need to remember in the future. 

KeePassX has all the tools you need to organize and keep track of your services, user names and passwords.  The Password Generator will create for you random passwords with the specified characteristic, could it be just numbers, or combination of numbers + Symbols + Uppercase + Lowercase.  For details check the project site, it is very easy to use and I’m sure in minutes you will start loving it.

Great! But… now we have two new problems:

1. We need KeePass(X) available all the time to have access to the passwords.
2. We have to keep the database file as safe as possible.  We can not afford to loose it!

The first problem is solved by another great product called PortableApps.  There is a KeePass Portable that I have installed on my memory stick so I can run it safely on any Windows Machine out there.  That’s the magic of PortableApps, check the site for details.

The second problem is solved by DropBox.  On my Laptop I keep the database file on the DropBox folder, so it is automatically backed up to the internet when I am online and every time I make a change on it.  DropBox will keep a copy of the file and even better will keep the different the versions as I keep updating it.  If I change the file by deleting an entry, or modifying one password by mistake, I can go to the DropBox site and recover previous versions.  Even if I delete the file by mistake, I can get the last saved version from the Internet.  There is also the copy on the memory stick, which I have to update manually, from the laptop, or from the site, so all the time I have 3 copies of the file. 

That is safe enough for me, and now I can even change the password often as recommended everywhere and not worry about forgetting them anymore.


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