HA! I had no idea dcraw now supported ACES directly now, that’s awesome!
As for the clipping, 16bit TIFF being an integer format is only an issue if you’re actually trying to store values above 1, which isn’t an issue at this point. It’s only when you scale up the “too dark” data.
More or less all RAW formats are 12 or 14bit integer black and white images. There isn’t anything “above 1”. Highlight recovery is either scaling down values that the default display transform deemed over exposed (but are still under 1 in the original RAW data), or values being interpolated from other unclipped channels.
If you want to get a really clear look at whats actually in your RAW files, use dcraw’s “document mode”
-d Document mode (no color, no interpolation)
-D Document mode without scaling (totally raw)
This basically dumps the raw un-debayered sensor data into a tif. From there you can really poke around and see what’s going on, even build you’re own debayer system from basic nuke nodes. (I’d recommend this as an interesting technical excercise, not a practical solution to debayering images).
As for ACR producing better highlights on the tape, I’d simply put that down to Adobe having more sophisticated highlight recovery. Whilst it’s not always the easiest tool to integrate, Lightroom is very impressive on that front.
That is exactly what I did. As I wrote in my post above I used “dcraw -v -o 5 -4 -T -H 2”
Did the -o 6 come with the update to DCraw 9.27? I am currently on 9.26 and it seems it is not working here. But thanks for the info!
Alex, do you have any information about how to integrate Lightroom in an ACES Workflow? Would be awesome if one could adjust a Rawphoto in Lightroom and export it into ACES colorspace after that.
Adobe Camera Raw (ACR) and Lightroom colour processing apply various non-linear adjustments to your images which will get in your way if your are trying to work with scene referred values:
Hue Twists which is a look up table embedded in the .dcp profile of your camera and usually attempts to bring the camera processed colours closer to those of a perfect colour rendition chart, it is also used for creative intent. Most of the time they are bad: http://dcptool.sourceforge.net/Hue%20Twists.html
So the first thing in order to get back into relative scene referred luminance values is to get rid of those two adjustments, it can be done by tweaking the .dcp profile of your camera. Lee Perry Smith has recently made a step by step tutorial on how to remove the Adobe Tone Curve here: http://www.triplegangers.com/index.php/blog/cat/technology/post/linear-pipeline/ and you can get rid of the Hue Twists by using dcpTool.
Once you have done that you could export to a regular sRGB or ProPhoto 16-bit integer tiff file and convert your values to ACES using your preferred method.
The caveat doing so is that you will have lost the extra dynamic range of your image (anything above 1.0 will be lost), there is unfortunately to my knowledge no elegant solution at the moment to keep it if you want to still work with Adobe tools.
Hi folks - I just joined this community and this is my first post here, so if I am posting redundant information, I apologize. If you are interested in using an ACES color workflow during raw conversion, including Canon CR2 files, you may want to take a look at the (Mac-only) raw converter called “Iridient Developer” - http://www.iridientdigital.com.
With the release of v3, the converter utilizes ACES with an sRGB tone curve as its internal working space and provides the capability to export your RGB processed image in that working space as well as whichever ACES ICC profile you may have installed on your machine. The quality of the converter itself is widely lauded in the photographic community, although it does not have the market presence of adobe.
Download the trial and take the time to work with some of your test images to see if this fits into your workflow.
very soon Filmlight will deploy its OnSet Look Development Tool “Prelight”.
There will be a free version too, to create Looks which can later be use in Postproductions.
Prelight as Baselight now debayers Still Raw Frames into scene referred Linear XYZ, from there Truelight Colour Space converts the data into any user specific working colour space like ACEScct.
This should allow you to create a Look based on a Still Camera and apply the Look to any other cinema camera’s output.
Just a little bit of a tease … we are working on a tool here that will be able to convert most digital still RAW formats to ACES. It’ll probably be a command line tool at first but it’ll provide multiple mechanisms to get from RAW to ACES depending on how much information you (or your raw file) has about your camera.
We are leveraging libraw and aces_container. There will also be custom code in it to create good IDTs from spectral sensitivity data if you have it. White balance in that case is also calculated from spec sense for a given light source but always user overrideable.
Right now we are using Affinity Photo.
It is working really good with 32bit, converts your RAW photos directly to ACES (or ACEScg) and has OCIO support. Especially the OCIO viewer process is very helpful.
The only thing that is missing is a batch convert function…
Could you provide some more details about your workflow with Affinity Photo? I’ve done some testing after reading your post, and by
Using the Develop Assistant to change Raw Output Format to “RGB (32bit HDR)” and Tone Curve to “Take No Action”
Pushing the Exposure slider 2 stops up on an already bright image, then switching from Develop Persona to Photo Persona
In the program preferences, setting the “32bit RGB Color Profile” to “ACES CG Linear”
Exporting as “OpenEXR 32-bit linear”
I was able to import the resulting .exr file into After Effects and recover all of the highlights from this intentionally overexposed image. Hard for me to know whether the file really is in ACEScg color space, but it is cool to get around Adobe Camera Raw’s display referred process. I couldn’t find an option for ACES AP0, though, just ACEScg AP1.
There is also (at least as of v1.5.2) a “New Batch Job” option that let me convert a folder of cr2’s into exrs, but it is completely unclear as to what options are being applied to the process - the resulting exr has a different exposure and a loss of detail from the single exrs I made using 16-bit or 32-bit, tone curve or no curve. I wouldn’t trust it without knowing more about what it’s doing.
Canon also present CR2 Converter for Windows. Below are overview of this tool. For its usage instruction refer to Canon 5d Manual.
Compatible OS:
Windows XP
Windows 2000
When you use EOS D2000, RAW images should be converted in advance using CR2 Converter for Windows.
CR2 Converter for Windows converts RAW images taken by EOS D2000 into RAW images with CR2 extensions so that they can be displayed/edited in Digital Photo Professional.
CR2 Converter for Windows is only available in English. You can download and install CR2 Converter for Windows in the same way as Digital Photo Professional Updater for Windows.
To start the CR2 Converter for Windows, open the [Canon] folder under the [Program Files] in the startup drive. Then double-click [omce.exe] in the [CR2 Converter] folder.
This is the workflow we are using as well. Sadly I have no clue what Affinity is doing under the hood to get those ACEScg pictures.
For AP0 output you could use the OCIO adjustment layer in Affinity.
The batch export is really a pain. As you said it is completly unclear what Affinity is doing there and why it is different from what is happening when exporting a single picture “by hand”.
I asked already in the Affinity forum, but did not receive any answer yet:
So, we are still searching for the perfect workflow. @Alexander_Forsythe do you have any updates for us?
Hello again!
I"d like to revive this thread. We did some tests with the rawtoaces tool and it works really nice. Finally something where we can batch convert a bunch of files.
One thing we discovered early is the highlight recovery function, which does not work as good as in Affinity Photo. As an example we took a .cr2 file from a Canon 5DMk2, overexposed by about 1 stop. After converting we leveled the resulting .exr files in Nuke to match the 50% greypatch and exported with the Rec709 ODT.
Converted to ACEScg with Affinity Photo without any changes:
Obviously rawtoaces is clipping the highlights with the default settings. With -H 3 the highlights are getting recovered somehow but there is a pink tint in the 2nd brightest patch and there are some artifacts on the yellow patch. Affinity is handling those parts really nice.
Is there anything one could do to improve those issues with rawtoaces?
I read about libraw about a “false” saturation level that could cause those pink highlights.
@kirkthibault Thanks for the link. I read through it a few weeks ago and its pretty interesting, but I cant translate it to the rawtoaces tool to be honest. I tried some saturation levels without any success.
