Adjusting curves in scanning makes sense?

[avieira]

Hello

I would like to know if when scanning I adjust the black/white point, curves, color...etc., if I get more information in the scan, compared with a Raw scan adjusted in photoshop (or any other SW including Silverfast).
In other words: Does the adjustments possible in silverfast change the way the scanner sees the image? or the scanner will extract always the same information and is only a question of post-processing (in Silverfast or any other SW). And, this applies to all scanner types? or is also scanner dependent?


Ant?nio

[RAG]

The adjustments you make during scanning are applied before Photoshop receives the file. If you are working with an 8 bit file you will not see any combing when the histogram is viewed in Photoshop. If, on the other hand, you adjust a raw 8 bit scan in Photoshop you will see combing in the histogram.

Does this answer your question?

[avieira]

The adjustments you make during scanning are applied before Photoshop receives the file. If you are working with an 8 bit file you will not see any combing when the histogram is viewed in Photoshop. If, on the other hand, you adjust a raw 8 bit scan in Photoshop you will see combing in the histogram.

Does this answer your question?

well, thanks, but it is not exactly what I was trying to figure out.
What I would like to know is basically if the scanner extracts always the same information that is treated after by silverfast, or if silverfast controls the scanner (for instance increasing the light strenght or exposure time) depending of the adjustements.

[RAG]

Well,

Through example, what I was trying to say is that even though the scanning software may process the information by controlling the scanner, what you end up with afterwards in Photoshop is an image file full of the information as presented. This is basically the same sort of processing one will find when using a Digital Camera. The processing is done by software after the image is captured by the hardware.

If you are scanning for archival purposes you will want to do raw un-processed scans and then work with derivatives of that file, but if you are trying to get the best possible images...

[avieira]

Well,

Through example, what I was trying to say is that even though the scanning software may process the information by controlling the scanner, what you end up with afterwards in Photoshop is an image file full of the information as presented. This is basically the same sort of processing one will find when using a Digital Camera. The processing is done by software after the image is captured by the hardware.

If you are scanning for archival purposes you will want to do raw un-processed scans and then work with derivatives of that file, but if you are trying to get the best possible images...

This means that the Raw format is not the best possible representation of a film. or am I understanding all wrong?

[RAG]

Well,

Let me see if I can help clarify. In technical terms a RAW image implies that absolutely no software manipulation of the image data has been applied. In the case of a Digital SLR Camera it is possible to adjust the camera settings and lighting to achieve a high quality RAW image. In the case of scanners, this is less likely, and in most cases it is not possible with a Digital SLR Camera. In comes post processing, be it in the Digital Camera, scanner software, Photoshop, or any other form of software.

Based on these sorts of factors, a RAW image scan may not yield the best possible representation. Adjusting the representation to your liking at the time of scanning essentially focuses your scans on the representation of your choosing.

[avieira]

Well,

Let me see if I can help clarify. In technical terms a RAW image implies that absolutely no software manipulation of the image data has been applied. In the case of a Digital SLR Camera it is possible to adjust the camera settings and lighting to achieve a high quality RAW image. In the case of scanners, this is less likely, and in most cases it is not possible with a Digital SLR Camera. In comes post processing, be it in the Digital Camera, scanner software, Photoshop, or any other form of software.

Based on these sorts of factors, a RAW image scan may not yield the best possible representation. Adjusting the representation to your liking at the time of scanning essentially focuses your scans on the representation of your choosing.

Thank you very much for your interest in clarifying, but... it did not help.

Let's forget photoshop (we can always make adjustments there nomather what we have done there), let's forget also digital cameras because it is clear that we can adjust exposition.

Let's imagine we make a scan and we make the adjustments (curves/black and white point... etc..) after prescan and then we make the scan.

Now we make the same scan in HDR mode. We open it again in silverfast and make the same adjustments like in the first scan.

Are the result of 2 steps equal? or the first one has better quality?
If the first one has better quality, means that somehow silverfast afects the way the scanner makes the scan (changing the light source strenght, exposition,... I don't know what). If they are the same it means that silverfast only post-processes the raw data that comes from the scanner and we can make Raw scans with confidence because we can always get the best possible result from it.


(thanks again)

[RAG]

In short it depends on your intended use.

You can most certainly get excellent representation for prints, video, and the web using both methods. The HDR method leaves you with a file containing all of the image information captured by the scanner that may be modified using future techniques, while the first method limits you to the image data you specified with your settings.

[avieira]

In short it depends on your intended use.

You can most certainly get excellent representation for prints, video, and the web using both methods. The HDR method leaves you with a file containing all of the image information captured by the scanner that may be modified using future techniques, while the first method limits you to the image data you specified with your settings.

do you have any idea who can I contact to answer my question?

thanks anyway :)

[RAG]

No problem. :-)

Let me see if this doesn't answer your questions. In short you can obtain equal quality either way, but HDR offers more flexibility in the long run.

[kirkgittings]

RAG,

I teach scanning at a university and private workshops. This is a point I would like some feedback on. You touched on it above.

If on an 8 bit scan one applies a steep curve to a file in Sf and the same to the flat file in PS, the PS file will comb, indicating to me that SF is applying the curve to raw data in the scan rather than 8 bit data after words. Is this true? Or is SF applying the curve in 16 bit and converting it to 8 bit?

If it is true does this not show up in a similar 16 bit comparison because of the depth of the 16 bit file?

I would think that any software worth its salt would apply adjustments like curves to the raw data much like Camera raw. Is this true? I have had many debates about this in the scanning community.

[kirkgittings]

I hope that is clear. I am a bit tired form being on a commercial shoot all day. This has been a hotly debated topic on the Large Format and Luminous Landscape forums as well as amongst my colleagues.

[kirkgittings]

Boy, not much life in this forum is there?

[Ian M]

Avieira posts an excellent question at the start of this thread and then explains very clearly what he needs to know on Feb 8th 2007 07:59. It seems to me that this question was never answered properly.
Perhaps someone else can have another go.

Thanks
Ian

[LSI_Morales]

Dear Avieira,
Dear Ian M,

If you make any adjustment in SilverFast, curves, white or black point, etc. It will be reflected in the end file unless you decide to make a RAW scan.
This also means the resulting file will be different, smaller histogram, less information in the modified file than the RAW file.

If you want to have the highest quality possible, you will have to make a RAW scan, from which you can make a copy for editing.