Blog

Gimp: Dynamic range compression (fake HDR)

Posted Sun, 07/03/2010 - 01:02 by mike

Hi folks,

in the RawTherapee forum a nice guy named ben_pcc offered source code for dynamic range compression (background to the algorithm). Since his results looked quite promising (and testing with just a source code file for RawTherapee is not so nice) I wrapped it into a small command line program and added a gimp script to call it. Binaries and source are attached.

The algorithm can be used to get a more even exposure on images with very high dynamic range, while preserving local contrast, so the image doesn't look washed out afterwards... With a little more work in gimp you can create fake HDR effects or a result similar to topaz adjust.

The attached image is a result of this filter and some post work in gimp; mainly local contrast and saturation. More results for this picture on flickr, original on deviantart.

So have fun experimentating and give tribute to the inventors and the author!

Drop me a line, if you like it. Smile

greets mike

UPDATE: Copy the script in the plug-ins folder of gimp, NOT in the scripts folder. And set it executable on linux.

UPDATE2: Ben wants to let you know, this algorithm is still work in progress. Also from my side, the script calling drc is just one way to do so, there could also be different workflows in the script calling it. So, if you have ideas or encounter problems, please tell me.

Gimp: Color gray decompose script

Posted Sat, 06/03/2010 - 14:23 by mike

Hi folks,

so here is the next gimp script, color gray decompose.

It converts your current layer (or view) into two layers, one containing the gray values and one containing the colors. With this decomposition it's possible to sharpen without color modification (like in LAB sharpen) or to alter the contrast of the image without altering the colors, i.e. the saturation. The other way round on can work on the saturation without changing the luminocity. To increase saturation, just pull the contrast up on the color layer, or use a S-curve on the color layer. When done, a simple merge down of the upper layer will give you your original image back...

Drop me a line if you like it or if you have ideas to improve it...

greets mike

 

Any ideas?

Posted Thu, 04/03/2010 - 01:10 by mike

Hi folks,

I'm thinking of the next steps with dlRaw...

Actually, it will finally become an open source photo editor, so bitmaps may be opened as well and exchange with Gimp is possible. It will be just an editor, since I think there are very good photo managers around (and I don't want to mess with them Wink ). However you can tag and rate your picture and digikam and F-Spot will understand this.

Happy Valentine's

Posted Sun, 14/02/2010 - 02:10 by mike

Hi folks,

I just want to spread my joy with a newly bought Pentax M 50 1.4 Laughing out loud The first pictures show one of the roses for my girlfriend Wink I also added one photo before editing process, to show what is left from nature...

I hope you enjoy them, greets mike

Update for webresize script

Posted Wed, 03/02/2010 - 23:01 by mike

Hi folks,

just to let you know, there is an updated version of the webresize script available. More information and download here.

greets mike