Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit

[Chris Cox]

Ray;

Photoshop is a straight color application, and OpenEXR is defined as being premultiplied.  This means that OpenEXR data has to be un-multiplied by the transparency/opacity values to work in Photoshop.  To a straight color application, there is no meaning to color values when the opacity is zero.  If the opacity is non-zero, then the color values are there -  just un-multiplied so they will composite correctly.

Photoshop already handles the EXR “A” channel (defined in the spec as opacity/transparency data) correctly – it opens it as opacity/transparency.
What the Photoshop EXR plugin does not do is give you a way to open the transparency channel as an arbitrary alpha channel, or to open channels other than RGBA.

I’m sorry I don’t have a solution for you, but your post sounded like you were confused about the terminology and what was happening to your data (enough so that I still don’t know what’s not working for you with the Photoshop EXR plugin).

Chris



On 6/4/09 4:23 PM, "address@hidden" <address@hidden> wrote:

> I'm working on a project that is rendering 32bit floating bit EXR files out of 3DStudio.  I'm then compiling these frames in After Effects in a 32 bit floating point composite and it's all working fine.  The problem I'm having is that I also need to composite some scenes in Photoshop CS4, and the default Photoshop EXR plugin is tossing out any data from the image that has a transparent alpha.  I found the Photoshop plugin on the OpenEXR website and had hopes that it would do what I needed.  Thankfully it knows how to handle the alpha channel properly, but unfortunately the plugin imports the image into a 16bit integer document and any value above 1.0 is clipped.  I can't use the exposure adjustment to access the over bright details.  Because of these import problems I have to run each image through After Effects and do the exposure processing there, then export an image to Photoshop.
>
> Can the maintainer of the OpenEXR photoshop plugin please recompile a new version that imports images into a 32bit document and maintain the full color range, or provide exposure controls in the plugin?  Also, I could use a 64bit version of the plugin for the 64bit version of Photoshop.
>
> Thanks,
>   Ray Collett
>
> --
> ========================================================
> --==--                 Ray Collett                --==--
> Technical Director; Newlands & Company Inc. www.nc3d.com
> ========================================================
>
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