Some of the intros and certainly some of the free special effects that you can find on the site use OpenEXR.

For many this is an unknown file format. For me it was no different...

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It was (VFX Master) Ben Watts who suggested, in one of his tutorials, to use Open EXR.

And he was damn right. (http://benwattsdesign.com/) 

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In the beginning, working with files as OpenEXR can look challenging. (and you could ask, why should I)

But it will turn out that it's easy as hell, and that working with them has almost only advantages!

(it makes things easy not difficult)

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Why than, can it seem so difficult. ( for me it seemed so anyway) And why did you possibly have not yet heard of it?

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For me it took a long time before I had even heard of openEXR, like many is this (VFX, film, ...) just a hobby that got out of hand. And like many I had no training in 3D software, similar programs or ways of working. I just wanted to blow things up with my computer. And make cool stuff. (Whatever that may be!) The first years, I was soon to find another solution when there was a difficult term that came up. And with OpenEXR, there are one or two. (which are actually not that difficult )

So that's why!

 

If you are a beginner,  now is the time to stop reading and go blow things up! 

Or you could be wise, by hoping that I'm going to explain the key points as short and good as possible!

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The advantages of using openEXR!

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A professional could say somthing like: "openEXR is a HDR file format with 16-bit floating-point color component values. Since the IEEE-754 floating-point specification does not define a 16-bit format, it's a "half" format. Half values have 1 sign bit, 5 exponent bits, and 10 mantissa bits. For linear images, this format provides 1024 (210) values per color component per f-stop, and 30 f-stops (25 - 2), with an additional 10 f-stops with reduced precision at the low end (denormals),..." 

 

The full explanation can be found at this address (http://www.openexr.com/)

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Probably the only effect it would have, is that you once again went to making the same crappy explosions!"

(I'm not saying mine are good)

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But to the point, what are the advantages!  

 

Over symplified: 

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Open EXR minimizes loss of information between programs, so that color correction, exposure  and compositing in post, are much easier​! A second advantage is the available alpha channel option! And optional other multi passes!

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Perhaps thats all you should now! Nevertheless, I think it's useful to know, more or less, where all the information stands for!

If you do, you can use it, why else would you even make the effort, to save that much information. (The files can be quite large)

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A few basic concepts of using openEXR!

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If you have a topic like this and you start to research it from scratch, then often one answer leaves  you with a whole bunch of new questions. Soon you lose a lot of time searching for information that appeared to be unnecessary at the end.

Therefore I have tried to summarize the key points for you!

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The key point if you ask me, is that you have a wide (high) dynamic range ( high amount of color information) available in a reasonably compact file format! (if you save your EXR file, you can choose different compression levels)

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But what exactly is dynamic range?

 

Let me start by asking a question, do you recognize this situation:

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"You have a particular file (photo, video, ..) or worse project, after hours of work right before you want to render the file. You just want to increase the contrast a bit and maybe highlight some of the blue tones, to obtain that cool cinematic look. You add a curves effect, but with the slightest adjustment that you make, your shadows immediately  apear way  to dark, or light areas way to bright. Once again your project is doomed to look,.. wel like ****!"

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t has to do with a linear workflow and color mapping, two technical terms which at first glance seem way too difficult (and boring) for Customized hobie'ist

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Having full high dynamic range, and an alpha channel at your disposal.

Are two big advantages of using OpenEXR!

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Having that much information, makes life much easier in post, (after effects for example) 

simply because you can adjust the exposure, to fit your composition. 

(one time it is dark,  the next time it is filmed during the day,...) 

And you don't need to deal with the green (or blue) of green screen footage.

The background is full transparent because of the alpha channel.

Yet you only need one file.

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It is true, using OpenEXR also comes with its challenges.

The files are large, even huge in some cases, (you can adjust compression methods to save disk space)

EXR files are image sequences, ( this has it's advantages as well )

it's not a native (os) file format, (you need additional software to preview in (Windows) explorer)

they ask a lot of your computer,.. (some graphics cards have build in EXR support: "nvidia geforce and nvidia quadro" )

At the end of the ride, it's really worth it. 

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