Archive for the ‘darktable’ Category

Darktable – Pimping clouds

Saturday, August 3rd, 2013

What can you do to make the clouds “pop” out of the sky? Do I hear “Buy polarizing filter”? Yep, it is kinda solution, but not in every case. Polarizing filters have some good effects:
– darken the blue of the sky and sharpening the clouds
– increase the saturation of blue and green
– reduce glare from leaves and other surfaces

And some bad sides:
– make water “transparent” and eliminate reflections – seriously, who would erase a beautiful reflection? I mean fishermen wear polarized glasses exactly for that reason – to see fish. But are you fishing or shooting? A good reflection is always good for the photo.
– polarizers work in specific direction – 90 degrees away from the sun. If you point it in any other direction it just won’t work.
– and because of that, forget using polarizers with ultra-wide angle lenses. Their field of view is 90+ degrees, so part of the frame will have the polarizing effect and other part will not. If you use it for a sky shot, one part of the sky will be darker than the other.

So, let’s see how we can recreate the advantages of using a CPL in Darktable. I will use this photo for demonstration:

I will use my favourite module “Color zones” under the “Color group”. Just drag the lightness of the blue to the ground. Optionally you can increase saturation of blue and green.

If you wish to make clouds more dramatic, you can use the “Local contrast” module under the “Tone group”. Usually I increase Detail to about 0.5, but here I have dragged it a little more to add pop.

And here it is the photo after these edits:

View from before and after:

This is part of the Darktable tutorials series.

Darktable – Fixing burnt out leaves

Saturday, July 27th, 2013

I like to shoot when hiking in forests. And I hate when I see photos after that 🙂

There are two factors that are photo-unfriendly in this case:
1. This happens around noon, so the sun is higher and casting harsh shadows.
2. This happens in good weather and clear sky – no one likes to hike if expecting a thunderstorm 🙂

When I shoot between trees what comes out of the photo is only hard shadows and bright sun spots. Like you see a pile of dalmatian dogs. One of the issues I’m encountering is with tree leaves – they just come out too bright, painting all the picture in dull burnt green.

Let’s check out a very regular photo:

At first glance you might say “What’s wrong with that photo, it is perfectly fine?” Yep, it is fine in terms that photo like this comes out of the most point and shoots and we are all used to see pictures like that. But it was not what we REALLY see in the wood. Where is that magic that takes your breath away and makes you to get out your camera? Seeing any magic here? Nope, only a blobby gray-green mass.

Here the folage is packed in the bottom and the top part. You can see the problem in the bottom part. It is more pronounced when you have more foliage.

There is a module in Darktable called “Color zones” that is under the Color group. It allows you to adjust lightness and saturation of only particular colors. In our case I want to darken the green, and maybe lower its saturation. It is one of my favourite modules and I certainly am going to show you more tricks with it later.

After that we get the following image:

Looking better, eh?

Question: isn’t it better to use the “Shadows and highlights” module?
Well, maybe. If you have other green objects in the frame, they will be adjusted along with the leaves, and that probably is not what you want. But it seems the highlights module alone is not capable to bring back too overexposed leaves.

Anyway, we have to remember that every photo is different and might need individual approach. There is no “magic setting” that works for every single photo.

This is part of the Darktable tutorials series.


Saturday, July 27th, 2013

When it comes to RAW editting sotware with Linux things are pretty dull in Linux.
There is lots of software like Adobe Camera Raw and Lightroom that are industrial standard, but unfortunately not working in Linux.
What were the options? For a long time there were no usable RAW editting software. There were converters and cmdline utilities, but these things were more developer-oriented than photographer-friendly. Until recently when Darktable emerged from the dark. It truned out to be very nice app with LR-like interface and tons of image settings. It is actively developed software whit new versions comming every month, providing lots of new features.
So, what is the problem with Darktable? It is very young application with not so big user base. Photographers preferred to work with Windows or Mac because of the mentioned lack of Linux software, and that is going to keep on for a while. Currently there is a deficiency of tutorials and helping readings. There are couple of video tutorials in YouTube, but 99% of these are in non-english language. When it comes to written articles, there is the User Manual that is very decent, but it is not a tutorial.

That’s why I decided to start a tutorial section here. It is going to be a series of short articles explaining how I have achieved this or that effect and I hope more people will get into Darktable. It will not be a “For dummies” one, explaining how to click the mouse and how to move a slider 🙂 You’d better have the User manual first.

List of articles:
1. Fixing overexposed foliage
2. Pimping clouds