On 21st of July Raw Therapee 2.4 has been released.

Raw Therapee (http://www.rawtherapee.com) is an open source (donation are appreciated of course) software for RAW development.

The 2.x versions are a big step forward with respect to version 1.x in terms of usability and some features (already included in version 1.x) are particularly interesting, especially how the RAW data are handled, achieving results in some areas better than most of other RAW converters, included the popular Adobe Camera Raw. Let's see.

The decoding of RAW data is done through the free and famous DCRaw (link here). The demosaicing algorithm (the process to pass from the RAW image in one-color to a "normal" color image) is selectable between 3 ones, and EAHD gives impressive results.

The first of Raw Therapee notable characteristic is the ability to extract details avoiding moirè (the false colors generated when a texture is too fine grained for the sensor resolution). At this link, Raw Therapee compares this on a test image from a Nikon D70 and it achieves the best result with comparison to all other popular RAW converters: DxO holds the second place though the rendition of colors is worse, Adobe Camera Raw is the third one with good colors, others (like Bibble or LightZone) are much worse, producing very visible moirè.

I personally reproduced the comparison with latest version of RawTherapee (2.4) and of Lightroom (2.4 too) that uses Adobe Camera Raw and RT is significantly better in this job, though at expense of a noiser image. You can download the raw images to prove it yourself and compare the outcomes with your favourite RAW converter (and add your feedback as a comment to this article).

A second very interesting characteristic of RT is the propagation of color for highlight recovery, a very useful feature in several situation, something we'd like to see in much more expensive RAW converters.

Basically, RT can propagate the last correctly displayed color into an area that is blownout instead of the common way to use grey (like Adobe Camera Raw and others do using the principle -where I cannot determine the color, I use the neutral grey-).

Take for example the common highlights on a human face because of the reflection of sunlight: we much prefer to see the blownout area as pink instead of grey, don't we? Look at an example here:

Normal highlight effect Color propagation effect
normal color-pro

Also sharpening algorithms seems to be good.

Typical corrections like cropping, white balance, free angle rotation, chromatic aberrations and vignetting are included. Also a basic lens distorsion is added (that Lightroom does not have to date...).

Version 2.4 improves the GUI and the file browser that has still some long road to run before competing with products like Lightroom or Adobe Bridge, but already snapshots and batch processing are there. For example image comparison is still missing.

Take into account that full EXIF support has just been introduced with this release so do not expect a catalog product, this is mainly a very interesting alternative to RAW development.

Also with version 2.4 you can send an image to an external editor.

Definitely worth a try (and I think also a donation to appreciate the very good work they are doing).

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