Post-Editing Options for HDR Output

All about SilverFast HDR and HiRepp (48bit HDR processing)

briank
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Post-Editing Options for HDR Output

Postby briank » Sun Jan 18, 2009 9:30 pm

I am new to Silverfast so I apologize if this question is too basic or has been answered elsewhere (although I have spent some time looking).

I am trying to figure out what my workflow should be (with an Epson V750-M) and have some questions about the option to output to 48 bit HDR. I think I understand that this is simply raw, unprocessed (and in the case of a negative, un-inverted) information from the scanner, and I understand that the benefit of using this option is that, at least if you have SilverFastHDR, you can play around and get the image the way you like it post-scan, whereas the tools found in the SilverFast scanning programs have to be applied at the time of the scan and cannot be used after (at least on that scanned image).

With that, I have two questions: (1) What are the file format options when you use this option? TIFF, PSD, JPEG, something else? (2) in order to post-edit this HDR output from my scanner, is SilverFastHDR the only option, or can this output be read by, and edited in, the latest iteration of Adobe Camera Raw (whether attached to Photoshop, Photoshop Elements or Lightroom); (3) Without asking you to make a qualitative comparison between programs, is their a functional benefit to using SilverFast HDR rather than some other program?

Thank you.

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Re: Post-Editing Options for HDR Output

Postby LSI_Morales » Mon Jan 19, 2009 3:32 pm

Dear briank

briank wrote:I am new to Silverfast so I apologize if this question is too basic or has been answered elsewhere (although I have spent some time looking).

I am trying to figure out what my workflow should be (with an Epson V750-M) and have some questions about the option to output to 48 bit HDR. I think I understand that this is simply raw, unprocessed (and in the case of a negative, un-inverted) information from the scanner, and I understand that the benefit of using this option is that, at least if you have SilverFastHDR, you can play around and get the image the way you like it post-scan, whereas the tools found in the SilverFast scanning programs have to be applied at the time of the scan and cannot be used after (at least on that scanned image).


So far you've got it right!

With that, I have two questions: (1) What are the file format options when you use this option? TIFF, PSD, JPEG, something else? (2) in order to post-edit this HDR output from my scanner, is SilverFastHDR the only option, or can this output be read by, and edited in, the latest iteration of Adobe Camera Raw (whether attached to Photoshop, Photoshop Elements or Lightroom); (3) Without asking you to make a qualitative comparison between programs, is their a functional benefit to using SilverFast HDR rather than some other program?

Thank you.


You should use the TIFF format option which is the only one which allow you to create uncompressed files without quality loss, those are also the only ones that can later be edited using not only HDR but other graphic and editing applications like Photoshop or Carmera Raw.
It is easier to transform the HDR pictures directly in HDR than other programs, for example while working with Negatives, you will find the same NegaFix profiles sets available in SilverFast SE or Ai which make the Negatives possitivation easier. Other advantage is converting 16 bits per channel into 8 bits because HDR is optimized to worked with files generated with SE or Ai in terms of gamma gradation, whereas using other programs you will have to assign this in many steps.
Alejandro Morales

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chuckhemard
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Re: Post-Editing Options for HDR Output

Postby chuckhemard » Wed Feb 25, 2009 11:56 pm

I am also considering a purchase of SF Ai and HDR and want to be sure it is best for my workflow. I plan to mostly scan MF color neg film (Nikon 9000), so using HDR to invert to positive would be helpful (as you mentioned). I also hope to use Adobe Lightroom software in my workflow (as I am familiar with the precision tools for basic tonal and color correction as well its asset management capabilities).

I am wanting to be certain that the process of using HDR (Negafix) to invert to positive based on a certain film type does not degrade the image data. In effect, isn't it like applying histogram adjustments in each color channel?

Also could you explain further your comments:
converting 16 bits perchanner into 8 bits because HDR is optimized to worked with files generated with SE or Ai in terms of gamma gradation, whereas using other programs you will have to assign this in many steps
?

i.e. Is changing modes from 16 bit to 8 bit in Photoshop not sufficient?

Thanks,

Chuck

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Re: Post-Editing Options for HDR Output

Postby LSI_Morales » Fri Feb 27, 2009 11:57 am

Dear Chuck,

Answering your questions

chuckhemard wrote:I am wanting to be certain that the process of using HDR (Negafix) to invert to positive based on a certain film type does not degrade the image data. In effect, isn't it like applying histogram adjustments in each color channel?


When you process the file in SilverFast HDR you will modify the original file to produce a second file which will have corrections, especially if you are going ot use NegaFix to make your possitives, a special color space with curves adjustments will be applied to every picture accordingly, however you do not save the changes applied to the original image you have scanned but you just export a second image which reflect the changes applied. It means the original picture will remain unmodified (in a way it remains as an untouched negative).

chuckhemard wrote: Also could you explain further your comments:
converting 16 bits perchanner into 8 bits because HDR is optimized to worked with files generated with SE or Ai in terms of gamma gradation, whereas using other programs you will have to assign this in many steps
?

i.e. Is changing modes from 16 bit to 8 bit in Photoshop not sufficient?


No, it is not enough to just switch from 16 bits to 8 bits in photoshop, the main reason is that 16 bit pictures contain much more information and details of the picture which can not be portrayed by your monitor (these are regularly 8 bits color), but the information is there. It is therefore necessary that you make the corrections first in 16 bits mode and at the end you make the conversion to 8 bits mode.
You will realize that 48 bits HDR pictures created with SilverFast will look underexposed (they are not underexposed, it is only that the portion of the histogram were the information is located can not be displayed by your monitor), in such cases you have to correct this value in using the histogram in Photoshop in 16 bits mode, after this adjustment you can then transform the picture into 8 bits mode.

Cheers
Alejandro Morales

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degrub
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Re: Post-Editing Options for HDR Output

Postby degrub » Sat Feb 28, 2009 2:48 pm

Regarding -
You will realize that 48 bits HDR pictures created with SilverFast will look underexposed (they are not underexposed, it is only that the portion of the histogram were the information is located can not be displayed by your monitor),

Last time i checked this was simply from no gamma being applied in the image file (ie: gamma=1). HDR applies the user set gamma to allow visualization of the mid and low tones in the image. Photoshop does not when the image is imported. This has nothing to do with the bit depth of the image, the monitor, or graphics card.

regards,

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Re: Post-Editing Options for HDR Output

Postby LSI_Morales » Mon Mar 02, 2009 10:38 am

Dear Degrub,

Thanks for your contribution, you are partially right, the pictures look underexposed because no gamma is applied to 48 bits HDR pictures. Even though photoshop does not apply a gamma correction automatically to those 48 bits HDR pictures created in SilverFast, you can make a gamma correction in the levels in photoshop, I recommended doing this correction before converting to 8 bits because you have much more information and picture details in the 16 bit file than the 8 bits file.
Alejandro Morales

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Re: Post-Editing Options for HDR Output

Postby RAG » Tue Mar 03, 2009 12:27 am

Hello Briank,

I was reading this thread and wanted to respond to your questions. The 48 bit HDR (High Dynamic Range) scan is effectively raw data captured from your scanner (In the case of a negative it does not produce an un-inverted image).

(1) The file format options are TIFF, JPEG, or JPEG 2000 and of these I would recommend TIFF. If you are scanning directly into Adobe Photoshop using the SF Plug-in and then save the file it will by default be a PSD.
(2) These files may be edited using Adobe Camera Raw or any application that can edit a 16 bit image (NOTE: LaserSoft identifies the total bit depth of all three colour channels (i.e. 16x3=48 bit) while Adobe identifies the bit depth of the individual color channel, so 16 bit in Adobe land).
(3) SF HDR has faster performance with larger files and gives you access to the same tools available in SF scanning applications.
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Re: Post-Editing Options for HDR Output

Postby LSI_Morales » Tue Mar 03, 2009 8:35 am

Dear Rag,

Thanks for your contribution

Cheers
Alejandro Morales

LaserSoft Imaging
Media manager, Software testing

briank
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Re: Post-Editing Options for HDR Output

Postby briank » Wed Mar 04, 2009 5:40 am

Thank you RAG. I think the clouds are parting a bit. However, I am a still a little unclear on one point. I was wondering if HDR was a proprietary format like NEF, for example. Hence my question whether ACR could open it, after which you would make your global adjustments in say, Lightroom, and then convert it into something like TIFF or PSD for further pixel-level editing in Photoshop. So I was trying to figure out if I could take the scanner data directly into Lightroom or whether I needed SilverFast HDR if I wanted to use an HDR output workflow. However, it sounds like you take the data from the scanner, immediately save it into one of the recognized non-proprietary file formats (e.g. TIFF), and then start editing in either SilverFast HDR or any editing program capable of 16 bit editing (i.e. ACR, Lightroom or Photoshop). Do I have that right?

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Re: Post-Editing Options for HDR Output

Postby LSI_Luebker » Fri Mar 06, 2009 12:11 pm

Dear Briank,

when using the HDR mode in SilverFast we simply produce a 48 Bit(color) or 16Bit(bw) Tiff file as you pointed out, It is possible to open these files with every application that support 48BIt Tiff files. The advantage of SilverFast HDR is that you have the options and settings as in SilverFast so you do not need to spend time familiarising with a whole new application and workflow but use all of your SilverFast knowledge.
best regards,

Thomas Luebker,
LaserSoft Imaging AG

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Re: Post-Editing Options for HDR Output

Postby LSI_Morales » Fri Mar 06, 2009 12:16 pm

Dear Briank,

You got it absolutely right, you can open your files with any application that supports 48 bits Tiff processing for further editing.

Cheers
Alejandro Morales

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Re: Post-Editing Options for HDR Output

Postby RAG » Fri Mar 06, 2009 5:05 pm

briank wrote:Thank you RAG. I think the clouds are parting a bit. However, I am a still a little unclear on one point. I was wondering if HDR was a proprietary format like NEF, for example. Hence my question whether ACR could open it, after which you would make your global adjustments in say, Lightroom, and then convert it into something like TIFF or PSD for further pixel-level editing in Photoshop. So I was trying to figure out if I could take the scanner data directly into Lightroom or whether I needed SilverFast HDR if I wanted to use an HDR output workflow. However, it sounds like you take the data from the scanner, immediately save it into one of the recognized non-proprietary file formats (e.g. TIFF), and then start editing in either SilverFast HDR or any editing program capable of 16 bit editing (i.e. ACR, Lightroom or Photoshop). Do I have that right?


I thought I saw some clouds. :-)

HDR is not proprietary like NEF, so while there currently isn't a SilverFast Lightroom plug-in, you are able to open the TIFF and JPEG HDR files in Lightroom. Now that you have this information, get to work! :-)
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medikoo
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Re: Post-Editing Options for HDR Output

Postby medikoo » Thu Aug 13, 2009 10:13 am

What's the options of editing HDR Raw file and saving it back to HDR Raw file ?

I noticed that while you can open HDR file in Photoshop, when you save it back to same format, it's not really Silverfast HDR anymore (I open it in Silvefast HDR studio and it's different - much darker)

Why do I need it ? - Let's say I want to export image to 3 different color spaces but raw scan has some dust spots and I want to clean them for final result. I know that I can clean them using HDR clone tool and then at once create 3 different files for each color space.. but what if I want to create another color space file the other day - I can't save modified RAW file back to RAW so I need to make those clean work again - that's bad.
Other thing is that Photoshop has better tools for such retouch - I would prefer to retouch with PS healing mask, save back to HDR Raw file, and then open it in Silverfast HDR and create files for desired color spaces. Would it be possible ?

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Re: Post-Editing Options for HDR Output

Postby LSI_Ketelhohn » Mon Aug 17, 2009 9:45 am

Dear medikoo,

Saving HDR back into HDR files would keep the file in the scanners colorspace insted of rendering it for example into AdobeRGB.
The main reason why HDR format is offered however is the possibility to import raw data from digital cameras.
Theses files can the be stored in HDR files for further processing.

Yes this is correct Photoshop automatically renders the image into a different colorspace (e.g. AdobeRGB).
True HDR images however contain the colorspace of the Scanner.
Also HDR images use an uncorrected gamma which makes them seem darker.
For different display systems this is changed.
Mac systems for example use a gamma of 1.8.
It is maybe possible Photoshop also adjusts this.

To keep your color workspace consistent you would have to make sure Photoshop uses the scanners color workspace and saves with it too.

kind regards
Arne Ketelhohn.

medikoo
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Re: Post-Editing Options for HDR Output

Postby medikoo » Mon Aug 24, 2009 11:24 am

LSI_Ketelhohn wrote:To keep your color workspace consistent you would have to make sure Photoshop uses the scanners color workspace and saves with it too.


I'm not sure is it that simple. I opened file in PS (CS4) made sure it's using Scanner profile (PS by default is using embedded profile). I saved it to other tiff file keeping same scanner color profile.. and while same color space is preserved, HDR Studio sees this new file differently (it's much darker than origin).

I've looked into meta data (exif) of new file and it looks that Photoshop adds its 2 cents and exif data differs in various places.
Probably the solution would be to edit new file so it has same meta data as origin.
Has anyone achieved any success on that ground ?


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