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Using SilverFast HDR

SilverFast Box

Tutorial - 2

Basic steps to optimising high-bit Scans

By Ian Lyons

 

27 September 2003

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A Computer Darkroom Tutorial

A question often asked of me is "why do we need SilverFast HDR?" Well, the simple answer is many professionals prefer to scan their images in "raw high-bit" and then save them to a Tiff file for latter processing. SilverFast HDR was designed to enable  the user to "process" existing image files (typically 16-bit Tiff or JPG files).

 

Unlike SilverFast Ai which has individual versions associated with individual scanner models HDR is designed to be used without a scanner. SilverFast HDR requires that your image have already been pre-scanned and saved as Tiff or JPG files. With SilverFast HDR the scanner operator can batch scan any number of images without worrying about colour/tone editing until such times as the edited images are required. The individual responsible for scanning might not even be concerned about final processing since this task can be passed-off to a more skilled person.

This tutorial will demonstrate two workflows for capturing raw high-bit scans from SilverFast Ai. It  also shows how to carry out a few basic corrections to the scanned image in SilverFast HDR.

The screenshots are all based on  Mac OS X of SilverFast Ai and SilverFast HDR. Nevertheless the basic layout of the various dialogs, etc. should be familiar to users of other operating systems

SilverFast Ai Scanner Set-up

Configuring SilverFast Ai to output your scans in raw high-bit mode isn't that difficult, but there are a few quirks that if left unattended too will cause no end of grief. If the steps outlined below are followed all should be okay.

In the following I assume that you are using Photoshop and are familiar with the SilverFast interface, although the screenshots should make things a bit easier to follow.

Step 1 - Getting SilverFast Ai ready for high-bit scanning

First we want to get SilverFast Ai set for raw 48-bit color output (LaserSoft call this 48 Bit HDR Colour mode). This is achieved by simply selecting the Scan Type pop-up and then choosing 48 Bit HDR Colour, as shown below.

 

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Setting SilverFast Ai for High Bit Output

 

You will notice that once 48 Bit HDR Color has been chosen ALL the colour adjustment tools are disabled, again this is normal, remember in high-bit mode you can't make, nor do you want to make any adjustments to the raw scan.

Next we want to get SilverFast Ai set for our preferred gamma-gradation setting. Anywhere between 1.8 or 2.2 seem to be the optimum values.

  • Press Option and then select the General tab.
  • Insert the required gamma-gradation value.

 

Image

 

  • If using SilverFast HDR with the IT-8 Calibration module or a custom created scanner profile the checkbox  labelled for HDR output should be left in the default unchecked state.

 

Important Note:  If you intend to scan negative type films and later use NegaFix it is again recommended that:- for HDR output is left unchecked and that you configure the CMS dialog as shown here - Click logo for instructions

 

 

Step 2 Configuring colour management for HDR colour mode

Different users appear to have widely varying views on how SilverFast Ai should be configured so that the raw HDR colour images are suitably prepared for later processing in SilverFast HDR. I'll describe two alternative workflows and have identified them according to two common user groups. Choose the one that best fits your needs, but don't try to mix the setting between them.

User Group 1 Configuration

This configuration is ideal for SilverFast Ai users who wish to save their 48-bit HDR Colour images with NO profile embedded and who will subsequently edit the high-bit images in a fully IT-8 calibrated version (optional extra) of SilverFast HDR. The raw scanned images resulting from this workflow will be very dark; this is normal.

 

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SilverFast Ai CMS Configuration 1

(48-bit HDR colour mode - don't embed a profile)

 

The CMS dialog should be configured as per the screenshot shown above, however, I have provided some further information below so that the choices may be better understood.

Colour Management

  • Input - > Internal - should be set to None. SilverFast Ai will not colour manage the image.
  • Internal - > Monitor - should be set to Automatic
  • Internal - > Output - should  be set to RGB

Profiles for ColorSync/ICM

  • Input - choose None. If a profile is selected it will be embedded in the exported/saved image and will likely conflict with the calibration profile associated with SilverFast HDR.
  • Internal - should be set for "your" preferred Photoshop working space, e.g. Adobe RGB (1998), ColorMatch, etc. As with Internal ->Monitor described above this selection will ensure that the preview image is displayed accurately on your monitor.
  • Gray - Not Important
  • Output/Printer - will be greyed out and therefore cannot be changed
  • Rendering Intent - ideally you should choose Perceptual or Relative Colorimetric

Embedded ICC Profiles

  • Embed ICC Profile - Uncheck!

Using the above configuration there will be no embedded profile.

User Group 2 Configuration

This configuration is ideal for those users who don't have any particular concerns about limiting the gamut of their original scans to the Photoshop working space. It's ideal for those who are using the SilverFast Ai IT-8 module; a third party calibration profile; or don't wish to leave colour management to SilverFast HDR.

 

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SilverFast Ai CMS Configuration 2

(48-bit HDR colour mode - embed work space profile)

 

The CMS dialog should be configured as per the above screenshot, however as before, I have provided some further information below so that the choices may be better understood. Note that you should begin by configuring the Profiles for ColorSync/ICM section.

Colour Management

  • Input - > Internal - Choose ColorSync/ICM.
  • Internal - > Monitor - should be set to Automatic - This setting ensures that the preview display will accurately reflect the image colours, tone and brightness.
  • Internal - > Output - should be set to RGB.

Profiles for ColorSync/ICM

  • Input - If Input -> Internal was set to ColorSync/ICM select the appropriate Scanner Profile otherwise None is acceptable.
  • Internal - should be set for "your" preferred Photoshop working space, e.g. Adobe RGB (1998), ColorMatch, etc.  Alternatively an archiving colour space such as EktaSpace or Kodak Pro Photo RGB could be selected. The selection made here will be the profile embedded within the exported/saved image.
  • Gray - Not Important
  • Output/Printer - will be greyed out and therefore cannot be changed.
  • Rendering Intent - ideally you should leave it at Perceptual or Relative Colorimetric

Embedded ICC Profiles

  • Embed ICC Profile - this should be checked

The embedded profile will be "your" chosen Photoshop working space as selected in the Profiles for ColorSync/ICM pop-up menu.

If your output is set for RGB then the remaining settings cannot be altered. Finally, click Apply followed by OK.

Contd.

 

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