Processing HDR files in Photoshop and Silverfast 8 Studio

SilverFast HDR Studio (48bit HDR processing)

bosveldboer
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Processing HDR files in Photoshop and Silverfast 8 Studio

Postby bosveldboer » Fri Feb 08, 2013 5:47 pm

Hi,

I have scanned a number of positive, reflective images with an Epson 4990 scanner and Silverfast 8, using 800dpi and 48bits HDR format in TIFF. I use OSX Mountain Lion. Images was scanned with Silverfast r19, while processing was done with r20.

My understanding is that the 48HDR file is in a standard, raw format with the Epson Scanner profile embedded and that it any color profile aware progrsm that can handle 16/bits per channel, should be able to read this file correctly.

Is this correct?

If I open these HDR files in Photoshop (CS6) the image is fairly dark, even if I chose the option that Photoshop should color-manage the image and use the embedded profile and convert it to the working profile Adobe RGB (1998).

If I open these HDR images in Silverfast 8 Studio and convert the profile to the same Adobe RGB (1998), the images are noticeably lighter and much nearer to the actual image.

Why is there a difference between how Photoshop and Silverfast interpret the HDR files with embedded scanner profile?

It looks to me that the HDR file format is not correctly interpreted by Photoshop, which means that the HDR file format is not a standard TIFF file.

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LSI_Ketelhohn
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Re: Processing HDR files in Photoshop and Silverfast 8 Studi

Postby LSI_Ketelhohn » Tue Feb 12, 2013 4:46 pm

Dear customer,

Sorry I had to correct this posting.
Apperently Photoshop can import the device colorspaces now.
I got that confused with another behavior.

However:
HDR(i) images should be opened and processed in SilverFast HDR (studio).

For Photoshop you should use the standard 48bit output.
These images are properly prepared for further adjustments in Photoshop.
SilverFast is optimized to to provide an image which is suited for professional work.
A 48bit Tiff will provide the best working base for further processing or direct use in a professional workflow.

kind regards,
Arne Ketelhohn.

bosveldboer
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Re: Processing HDR files in Photoshop and Silverfast 8 Studi

Postby bosveldboer » Wed Mar 06, 2013 7:26 pm

Dear Sir,

I have not yet received a satisfactorily answer to why there is a difference between the appearance of 48HDR RAW TIFF images imported into Silverfast 8 HDR and Photoshop CS6.

In each case, the program is set to use the embedded scanner profile and to convert to RGB (1998). In both cases, the working space is set to RGB (1998).

The Photoshop image is noticeably darker than the Silverfast image and the color is also not the same.

The only explanation is that the Silverfast 48HDR Raw image files with embedded scanner profile is not a standard TIFF file.

I can send you an example of such files if you want to re-create the problem.

Please help

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LSI_Ketelhohn
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Re: Processing HDR files in Photoshop and Silverfast 8 Studi

Postby LSI_Ketelhohn » Tue Mar 12, 2013 9:23 am

Did you adjust the gamma value in Photoshop?

The HDRi images are saved unchanged without any gamma adjustment.
SilverFast HDR (Studio) automatically adjusts the image to a gamma of 2.0.


kind regards,
Arne Ketelhohn.

Faurean
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Re: Processing HDR files in Photoshop and Silverfast 8 Studi

Postby Faurean » Thu Apr 18, 2013 7:45 pm

My apologies for jumping into this thread.

What does the Silverfast Photoshop Bridge do? I noticed it during the installation of a new SF8 Archive. Photoshop Elements 11 opens HDR files "correctly", in my unexpert opinion, but they do need processing and tuning.

AHF

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LSI_Ketelhohn
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Re: Processing HDR files in Photoshop and Silverfast 8 Studi

Postby LSI_Ketelhohn » Fri Apr 19, 2013 4:24 pm

The Photoshop Bridge module is used for importing images from Photoshop's import menu.

The 48/64 bit HDR(i) images are raw, unchanged archive images.
These are intended to be processed in SilverFast HDR (Studio).

Kind regards,
Arne Ketelhohn


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