Settings used in HDR Scans

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bosveldboer
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Joined: Wed Jan 02, 2013 1:19 am
Scanner: Epson 4990
SilverFast Product: Archive Suite

Settings used in HDR Scans

Postby bosveldboer » Tue Apr 09, 2013 11:51 pm

Hi,

An assistant scanned a large number of reflective images in 48HDR mode, but unfortunately did not remember or note down what settings was used for scanning.The scanning was done with Ai Studio 8.0.1 (r20,r21 and r20) on OSX with Epson 4990)

In particular, I do not know if the option gamma for HDR output was ticked or not and what the actual gamma graduation was when the scan was done.

How I can find out from the saved HDR files what the settings were?

Which settings are important to know to be able to process the HDR files in HDR Studio?

I will replace the embedded profile (if any) with a new calibration profile that I will do with a IT8 target on the Epson scanner. Is there anything that I need to know or set before doing the calibration?

Regards

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LSI_Ketelhohn
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Re: Settings used in HDR Scans

Postby LSI_Ketelhohn » Tue Apr 16, 2013 4:14 pm

Dear customer,

As long as the HDR files were saved into TIFF files it is not necessary to obtain this information.

SilverFast HDR (Studio) will automatically recognize the used gamma from the files metadata.

For HDR images saved into JPG2000 this function is available from version 8.0.1r21 on.
However TIFF is the standard file and as long as you did not change this (or change the files metadata) you will not have to worry about this setting.

kind regards,
Arne Ketelhohn.

bosveldboer
SilverFast Beginner
Posts: 23
Joined: Wed Jan 02, 2013 1:19 am
Scanner: Epson 4990
SilverFast Product: Archive Suite

Re: Settings used in HDR Scans

Postby bosveldboer » Mon Apr 22, 2013 1:43 pm

Dear Sir,

I now understand that HDR Studio will recognise the gamma used.

However, how do I determine from the TIFF files what the actual gamma was, as some scans are destined for processing by programs other than Silverfast HDR Studio ?

Regards

bosveldboer
SilverFast Beginner
Posts: 23
Joined: Wed Jan 02, 2013 1:19 am
Scanner: Epson 4990
SilverFast Product: Archive Suite

Re: Settings used in HDR Scans

Postby bosveldboer » Tue Apr 23, 2013 8:37 am

Hi,

I am confused again and we need a more thorough explanation of the HDR archiving standard you uses.

My understanding is that images saved as HDR TIFF files by Ai Studio, have the raw scanner data in the file without any processing or conversion or gamma.

Question 1
Your answer above implies that the gamma, set by the user during the scanning process, is applied by Ai Studio during the scanning process and that HDR Studio uses that gamma. In this case, it is no longer the RAW data in the file.
Does Ai Studio uses and applies the gamma during the scanning process to images saved as HDR files or not?

Question 2
There is an option in Preferences "for HDR output". I understand that when ticked, Ai Studio will put the gamma used in the HDR file.
Does Ai Studio applies the gamma to HDR files or only saves the gamma set by the user when this box is ticked?

Question 3
If the box "for HDR output" was NOT ticked in Ai Studio and a gamma of 1.8 was set by the user, how will Ai Studio handle gamma when saving the images as HDR TIFF files?
Does it apply gamma?
Does it save gamma in the HDR file?

Question 4
In Preferences, there are two gamma settings. "Gamma Gradation" and "Gamma in 48bit/HDR" and tghe tick box "for HDR output"
Which gamma is used and put into the HDR file if the tick box "for HDR output" is ticked?


Question 5
In HDR Studio, what is the use of the Preference option "Gamma in 48Bit/HDR file" ?
Does HDR Studio uses this gamma or the gamma you said where saved in the HDR file by Ai Studio?
If this gamma is different from the gamma saved in the HDR file, which gamma is used?


Please allow me a general comment. You have excellent software, but you need to decide if you want to target the professional market or the amateur / hobbyist market. For the professional market, you need much better documentation, fine-tuned, flexible options and settings that DOES NOT REVERT back to default all the time. Professional users have unique needs and they want to be able to set any combination of preferences and options to match their requirments for a particular job and they do NOT want the software to keep reverting back to your normal all the time. This has already wasted a lot of my time, because you assume that if yiou set someting in Preferences, it will stay set and not revert back.

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LSI_Ketelhohn
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Re: Settings used in HDR Scans

Postby LSI_Ketelhohn » Tue May 07, 2013 11:02 am

Dear customer,

You can apply a custom gamma value to a HDR scan but you do not have to.
The standard HDR file will not adjust the gamma level.
The user set gamma is only applied if the "for HDR output" checkbox is active, that is correct.

The "Gamma in 48Bit/HDR file" sets the gamma for HDR images in case the gamma is not saved correctly in the file.
Or in some cases if that information was deleted by another imaging software.

We mainly offer documentation through the various tutorial movies.
Our PDF documents will also be extended further.

kind regards,
Arne Ketelhohn


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