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32bit output from ACR when processing HDR images

Jun 22, 2012 12:46 AM

Tags: #float #32bit #hdr #32bit_float #hdri

As said above, why does ACR not support 32bit output for HDR images that are processed in it?

I read this discussion too, but since the situation changed now, it would be nice to have 32 bit output from ACR.


Is there still anything that speaks against it?

  • Noel Carboni
    23,496 posts
    Dec 23, 2006
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    Jun 22, 2012 8:33 AM   in reply to Joe_Mulleta

    Hi Joe,


    Something went wrong with the link you posted.  I'd be interested in reading the past discussion on the subject.



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    Jun 22, 2012 12:13 PM   in reply to Joe_Mulleta

    The way in which I manage this is to batch-convert a series of progressive exposures in ACR 7.1;


    Select all of those files in Bridge and use Tools/Photoshop/Merge to HDR Pro and

    Save as 32-bit.tif (floating);


    Then open that Tiff in ACR 7.1 to refine the editing (making full use of the Adjustment Brushes);


    Finally, I open the file directly from ACR into Photoshop CS6 as a ProPhoto RGB 16-bit Smart Object and finish the image.


    This works beautifully and produces very smooth and wide DR images without those horrendous HDR grunge haloes.


    While you could do part of this in LR 4.1 if you wished, you do need Photoshop CS6 for some of the steps.

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    Jun 24, 2012 7:58 AM   in reply to Joe_Mulleta

    Hi Joe,


    Our design of ACR/LR is to render images for display or print.  When starting with scene-referred images (e.g., raw), this means tone and color mapping the input linear light data (e.g., whether 12-bit integer or 32-bit float) to values suitable for reproduction (output-referred).  Since the resulting is always intended to be output-referred, the resulting images are always stored using 8-bit or 16-bit values.  We do not see any need to represent output-referred data using 32-bit values. 


    (ACR/LR is not intended to be a "pass-through" system that can, say, take 32-bit image data as input and also emit 32-bit image data at the end.  It can be made to do so, though clumsily.)

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    May 12, 2013 4:30 AM   in reply to MadManChan2000



    As stated in this thread: I do indeed see a very important use for being able to export floating point files, once you export as tif file, your dynamic range is lost, this is very problematic when you have to create HDRI files and still benefit from ACR Undistortion and Camera Profile.



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