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tag: Highlights

Visualizing the raw (sensor) highlight clipping

Have you ever over-exposed your images? Have you ever noticed that your images look flat and dull after you apply negative exposure compensation? Even though the over/underexposed warning says there is no overexposure? Have you ever wondered what is going on? Read on.

the problem

First, why would you want to know which pixels are overexposed, clipped?

Consider this image:

rawoverexposed-0

… Why is the sky so white? Why is the image so flat and dull?


Color Reconstruction

If you overexpose a photo with your digital camera you are in trouble. That’s what most photography related textbooks tell you – and it’s true. So you better pay close attention to your camera’s metering while shooting. However, what to do when the “bad thing” happened and you got this one non-repeatable shot, which is so absolutely brilliant, but unfortunately has some ugly signs of overexposure?

In this blog article I’d like to summarize how darktable can help you to repair overexposed images as much as possible. I’ll cover modules which have been part of darktable for a long time but also touch the brand new module “color reconstruction”.


Shadow recovery revisited

One of the remaining shortcomings of digital cameras is their rather low dynamic range in comparison to analog – especially black-and-white – film. Scenes with strong differences between highlights and shadows are very difficult to capture. Even if they are exposed properly with no blown-out highlights they will too often only give acceptable results after extensive post-processing.

Fortunately, darktable is progressing with a high pace. Some days ago I wrote an article on how to recover shadows with a technique using lowpass filter plus blend mode (" Using lowpass filter to recover shadows "). In between a new, even better module called “shadows and highlights” was integrated into darktable, that obsoletes this technique.


Using lowpass filter to recover shadows

Outdoor photographers are often confronted with unfavorable light conditions. This often entails too high contrast. Two of the most frequent consequences are blown highlights and deep shadows in your digital images. Overexposed highlights are challenging to repair in digital post post-processing, still darktable offers a decent set of valuable tools as long as you take your pictures in raw (see Jo’s blog post “ why you want raw ”). Fortunately, it’s much easier to take care of the deep shadows.

why you want raw

or: how to rescue your shot after the fact.

also: how to use color zones for black and white.

sometimes i’m surprised by what kind of data is hidden in my raw images, and i want to pass this on to those of our users who happily take pictures in jpg. actually it’s just a short story about a typical communication problem between me and my camera and the way darktable moderates that, after the fact.