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Author Topic: merge to 32bit in Lightroom  (Read 8520 times)

Robert-Peter Westphal

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merge to 32bit in Lightroom
« on: September 23, 2012, 08:01:44 am »

Dear all,

my first thread concerning this topic disappeared, so I try to recover it from my mind :

Photomatix recently released a Lightroom plugin called 'Merge to 32-bit HDR Plug-in for Lightroom' which you can you to export a set of images, align them and reimport as one 32-bit image which can now be tonemapped in Lr. I'm wondering if it will be a difference in imagequaltity when doing this by the plugin of Photomatix or with the help of PhotoShop.

I cannot try it myself becasue I'm still on PS-CS4 and not sure whether I should do the upgrade to CS6 ( I bearly use PS ).

My hope was that Adobe would integrate this function in Lr, but I fear that this is the stuff the next version of Lr could be made of.

So, does anyone can help me ?

Robert
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RFPhotography

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Re: merge to 32bit in Lightroom
« Reply #1 on: September 23, 2012, 10:16:08 am »

Yes, LR can now import and edit 32 bit TIFF files.  But only TIFF files. 

You can send a set of images from LR to Photoshop for merging in HDR Pro.  You can then save that 32 bit file in PS as a TIFF and bring it back into LR for editing (tonemapping). 

Each will use different algorithms for merging the source files to create the 32 bit image so there will be differences between the two.  Whether one or the other method will be better is a matter of personal preference.  You can do with with CS4 because HDR merging was implemented in CS3.  HDR Pro came out with CS5.  If you select your set of bracketed images, right click go to Edit In do you see Merge to HDR as an option?  I can't remember to be honest if there was an LR path to CS4 for HDR merging or not.  If there isn't, you can do it from Bridge.
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Robert-Peter Westphal

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Re: merge to 32bit in Lightroom
« Reply #2 on: September 23, 2012, 12:21:45 pm »

Hi Bob,

many thanks for your answer !

Surely I can use CS4 for merging the single images, but I will have to convert them to DNG 6.6, because the ACR for CS4 doesn't know my camera. And, as far as I could see with a quick test, when exporting the DNGs to CS4, I loose all changes I did in Lr.

So, this is not really an option for me.

Robert
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RFPhotography

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Re: merge to 32bit in Lightroom
« Reply #3 on: September 23, 2012, 12:36:23 pm »

You don't need CS4 for the RAW files.  If you export from LR to merge to HDR in CS4, Lightroom should be the engine that's used to send the files.  If that's not working, then convert the files to TIFF in LR then send those TIFF files to be merged in CS4.  When you use the Photomatix plugin to export RAW files to Photomatix, that conversion (to TIFF or JPEG, whichever you choose) is being done.  So if you send TIFF files to CS4 to be merged, it's really no different.
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Robert-Peter Westphal

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Re: merge to 32bit in Lightroom
« Reply #4 on: September 23, 2012, 12:53:38 pm »

In the settings of lightroom the export for the 1st external editor which is Photoshop CS4 is set to 16-bit TIFF, ProPhotoRGB and 300DpI.
So, when I do ra right click on the two marked images, choose edit in - merge to HDR, there is a message stating that ACR 7.1 is needed. When pressing OK, Photoshop CS4 is started, but nothing else happens.

So I assume, when the images for HDR is sent to PS, it uses ACR to render the TIF and the last ACR of CS4 doesn't know my camera.

Robert
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Bryan Conner

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Re: merge to 32bit in Lightroom
« Reply #5 on: September 23, 2012, 01:29:25 pm »

In the settings of lightroom the export for the 1st external editor which is Photoshop CS4 is set to 16-bit TIFF, ProPhotoRGB and 300DpI.
So, when I do ra right click on the two marked images, choose edit in - merge to HDR, there is a message stating that ACR 7.1 is needed. When pressing OK, Photoshop CS4 is started, but nothing else happens.

So I assume, when the images for HDR is sent to PS, it uses ACR to render the TIF and the last ACR of CS4 doesn't know my camera.

Robert

I am very much interested in this too.  I use Lightroom 4 with CS5.  If I send images to be converted in HDR in CS5, is Lightroom processing in PV 2012, or is CS5 processing in PV 2010?
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digitaldog

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Re: merge to 32bit in Lightroom
« Reply #6 on: September 23, 2012, 01:48:04 pm »

So I assume, when the images for HDR is sent to PS, it uses ACR to render the TIF and the last ACR of CS4 doesn't know my camera.

Correct.
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RFPhotography

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Re: merge to 32bit in Lightroom
« Reply #7 on: September 23, 2012, 03:15:15 pm »

OK, then yes.  As I said I couldn't remember whether LR did the conversion or PS/ACR.  There are times when you try to export a file to PS out of LR it will ask you whether you want to render it using LR or ACR.  Guess this isn't one of those.

In that case, convert to TIFF in LR and send those to CS4 for merging.
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madmanchan

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Re: merge to 32bit in Lightroom
« Reply #8 on: September 24, 2012, 08:14:53 am »

To process floating-point HDR images in ACR you will need ACR 7.1 or later with PV 2012.  (You can use PV 2010 and earlier but it will not preserve the floating-point data during the rendering and hence in a truly high contrast scene you will likely see banding/quantization artifacts in the shadows.)

The two floating-point HDR formats that ACR / LR currently support are TIFF and DNG.
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Eric Chan

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Re: merge to 32bit in Lightroom
« Reply #9 on: September 24, 2012, 08:27:56 am »

Hello Eric,

many thanks for your answer !

Does that mean that when converting the source-files in Lightroom 4.2 to DNG 7.1, I still can use CS4 to do the merge and creation of the 32-bit file and then do the tone-mapping in LR ? Or is this the constellation which creates the artifacts you weree describing ?

Robert
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Re: merge to 32bit in Lightroom
« Reply #10 on: September 25, 2012, 03:49:03 pm »

To process floating-point HDR images in ACR you will need ACR 7.1 or later with PV 2012.  (You can use PV 2010 and earlier but it will not preserve the floating-point data during the rendering and hence in a truly high contrast scene you will likely see banding/quantization artifacts in the shadows.)

The two floating-point HDR formats that ACR / LR currently support are TIFF and DNG.

I also have CS4 and LR 4.1. Export in LR to TIFF's with PV2012. Then select all the TIFF's in LR and choose "Merge to HDR". Do this workflow also introduce the artifacts you describe?
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madmanchan

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Re: merge to 32bit in Lightroom
« Reply #11 on: September 26, 2012, 08:48:52 am »

Does that mean that when converting the source-files in Lightroom 4.2 to DNG 7.1, I still can use CS4 to do the merge and creation of the 32-bit file and then do the tone-mapping in LR ? Or is this the constellation which creates the artifacts you weree describing ?

Hi Robert, yes, you can use older versions of Ps to do the merge-to-HDR.  Just make sure you choose "32 bit" as the data type in the Merge to HDR dialog box, and that you save the file in TIFF format (you can choose either 16, 24, or 32 bits of precision per channel).  The resulting TIFF can then be processed in Lr 4.2 in PV 2012 for tone mapping.
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Eric Chan

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Re: merge to 32bit in Lightroom
« Reply #12 on: September 26, 2012, 08:51:57 am »

I also have CS4 and LR 4.1. Export in LR to TIFF's with PV2012. Then select all the TIFF's in LR and choose "Merge to HDR". Do this workflow also introduce the artifacts you describe?

No, there should be no artifacts this way.
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Eric Chan

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Re: merge to 32bit in Lightroom
« Reply #13 on: September 26, 2012, 01:46:02 pm »

Thanks for clearing these questions up.  I appreciate the fact that you take time to share your knowledge and help us by educating us in such a nice way.  Your presence is refreshing on LuLa.
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Robert-Peter Westphal

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Re: merge to 32bit in Lightroom
« Reply #14 on: September 26, 2012, 02:22:10 pm »

Hi All,

many thanks for helping with this question.

I've got one question left : Does it make any difference when converting my source-files for HDR to DNG 6.6 or 7.1 ?

Robert
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s4e

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Adjustments before merge to 32 bit HDR?
« Reply #15 on: September 26, 2012, 03:53:35 pm »

Thank you Eric. I also enjoyed you as guest star in the video!

What should be adjusted in LR before merge to HDR?

WB? Camera and lens calibration? Neutral curve?



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RFPhotography

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Re: Adjustments before merge to 32 bit HDR?
« Reply #16 on: September 26, 2012, 04:37:22 pm »

Eric, how do you save a 32 bit file as DNG in Photoshop.  It's not an option in the Save As dialogue.

Thank you Eric. I also enjoyed you as guest star in the video!

What should be adjusted in LR before merge to HDR?

WB? Camera and lens calibration? Neutral curve?


The HDR software wants linear files as inputs.  What it will do is reverse out the gamma curve built into the colour profile the image is tagged with.  If you do any other adjustments with tone curves this could impact the ability of the HDR software to create linear image files for merging.  It's better to leave things like tone curve, hue/saturation, etc. untouched prior to HDR merging.  Another reason for this is that these adjustments can become quite enhanced via the HDR merging process which can leave you with less desirable results.

Prior to merging you want to make sure your white balance is 'correct'.  When I say correct I'm talking as neutral as possible.  Any WB colour cast can get exaggerated in the HDR process and be difficult to correct later on.

Lens aberrations can also be taken care of before merging.  Better done at the RAW stage than later on.  LR or ACR can use a lens profile for distortions and any CA is easier dealt with on the RAW file than later on.  If I'm doing things like perspective distortion on architectural images, I do that after merging/tonemapping.

The last adjustment that can be done before merging is cloning/healing.  This one isn't as important and can be left till after if you want.

All three of these can be applied to one file in the bracketed set and synced to the others.

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I've got one question left : Does it make any difference when converting my source-files for HDR to DNG 6.6 or 7.1 ?

Robert, you can convert to TIFF as well and the HDR plugin for CS4 will read those files too.  If you're going to use DNG, it really shouldn't matter if it's 6.6 or 7.1. 

In all honesty though, I wouldn't bother using Lightroom for processing 32 bit files.  32 bit TIFF files are HUGE.  Adobe really needs to step up and provide support for .exr and .hdr files as well.  What you can do with 32 bit files in LR is quite good.  I did some comparisons earlier this year and posted a couple on my Facebook Page.  Both were tonemapped in LR, one was merged in Photomatix, the other in HDR Pro.  Highlights and shadows were handled quite well.  This scene had, if I recall, about a 16 stop range.
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jrsforums

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Re: merge to 32bit in Lightroom
« Reply #17 on: September 26, 2012, 05:46:05 pm »

Nice example, Bob....

Thanks
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John

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Re: merge to 32bit in Lightroom
« Reply #18 on: September 26, 2012, 06:04:03 pm »

I now bought the "Merge to 32-bit HDR Plug-in for Lightroom". Gives much better results than CS4 and very easy to use without getting a lot of temporary TIFF files because of the  >:( interface between LR and older versions of CS.

The plugin have a option of using "Half Floating Point Format" that reduce file size by half. "The Half Floating Point format is appropriate for storing very large variations in brightness, as it is used by OpenEXR, the most popular 32-bit HDR image file format."
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