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Date: Mon, 11 Feb 2008 22:28:26 -0500
From: Edward Lam <edward@sidefx.com>
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To: Chris Cox <ccox@adobe.com>
Subject: Re: [Tiff] 32-bit floating point RGB images (and gamma)
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Status:   

Chris Cox wrote:
> Now, Photoshop DOES correct for the display -- your gamma 1.0 image will
> look correct on the display because Photoshop converts the data to the
> display gamma (and chromaticities) when displaying the image.

Indeed, this fact had escaped me. I was lead astray when I sought for 
reasons why the might be interpreted differently and found the 
TransferFunction tag.

Thanks,
-Edward

> On 2/7/08 7:27 AM, "Edward Lam" <edward@sidefx.com> wrote:
> 
>> Hi Folks,
>>
>> What's the best way to express a TIFF file that has 32-bit floating
>> point, *linear* RGB data? If I do the dumb thing, then Photoshop CS3
>> Extended interprets the data with a 2.2 gamma. However, ImageMagick
>> seems to display the image without the gamma correction.
>>
>> Looking at the TIFF 6 spec, the default TransferFunction seems to be 2.2
>> gamma correction if unspecified for RGB PhotometricInterpretation?
>> However, one can't easily provide a linear TransferFunction for 32 bits
>> per sample data.
>>
>> Thanks,
>> -Edward
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> 

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