|
Overview of NegaFix
NegaFix is a
real-time negative film optimisation facility that has been
designed to handle many different types of negative film stock,
e.g. Black and White and
of course Colour. LaserSoft Imaging have initially included
120 film
profiles so that the process of editing negatives is now easier than
ever before. The film options include: vendor, type, group and speed.
Best of all NegaFix is compatible with the full range of scanners currently supported
by LaserSoft Imaging, including Nikon. I've been
fortunate enough to use the new version of SilverFast on the
Polaroid SprintScan 4000 and 120 models along with SilverFast
HDR. The following is a summary of the various controls
and brief overview of how NegaFix
works.
Step 1 - Getting SilverFast ready for negative
scanning
After opening SilverFast Ai or HDR
we must configure SilverFast for negatives, this is done from within
the "General" tab of the main control
panel. Once the user chooses to scan a negative the NegaFix
control panel should appear on the desktop.
Selecting the Film Type
- Positive/Negative
Insert the "Uncut"
filmstrip holder into the scanner gate. If you've previously
scanned negatives a preview of the last image will appear along
with the NegaFix control
panel shown below.
NegaFix
Control
Panel - Basic Configuration
Step 2 - SilverFast
Colour Management
In order that the final scan matches the preview screen it's important that the
"CMS" dialog found in the "Option" panel is configured as shown below. Actually SilverFast
reconfigures itself when
NegaFix is selected.
Specifically, users will find that SilverFast automatically disables the calibration profile and defaults to
"None" and the Input profile is ignored.
In the Profiles for ColorSync/ICM "Internal" choose the colour space that corresponds with what you have chosen in Photoshop. When
NegaFix is chosen this is the profile that will be embedded in our images. SilverFast ignores the scanner or calibration profile, although the preview display will still be correct.
Configuration of Colour
Management Dialog
Step 3 - Creating the overview scan
By
pressing the  button
the "Overview" window will appear. Simply choosing the "Refresh
Overview"  button will cause the scanner to quickly create a
group of thumbnails for each image on the filmstrip. Make your choice
and press "OK".
Overview scan of images available
on film strip
Step 4 - Making the pre-scan
From
the "Frame" tab
select your scan resolution, etc. Of course make sure the "Q-factor" is set to "1" and the "Filter" is set for "None".
Also ensure the tool palette looks like the one shown below, otherwise
hold down the "Alt"
key and press the "Option"
button to reset all previous corrections. This step MUST be
undertaken so that we may be sure that the characteristics of the
previous scan are not carried over.
You can now press the "Prescan"
button and watch the image appear on screen. Typically the
pre-scanned image will look bad, this is almost always down to the
cropping boundary not being correctly set. To ensure correct
operation of NegaFix it is essential
that the cropping boundary for the pre-scan image is set so that NOTHING
other than the actual image is included.
Step 5 - Choosing the film type and exposure
(Basic mode)
Using NegaFix in Basic
mode amounts to carrying out six very simple tasks. They are:
-
Crop the image so that frame margins are excluded.
-
Select a film manufacturer.
-
Select a film type.
-
Select a film speed.
-
Adjust the manual exposure slider.
-
Apply Auto Adjust tool.
The NegaFix control panel
offers three pop-up menu options and an exposure slider. The
three pop-up menus are where we choose the film-maker, type and
speed.
Selecting the Film
maker for the NegaFix
Control Panel
The exposure slider (circled red in the screenshot below) enables adjustments of approximately
plus or minus 3 f-stops. The preview display is continually
updated as the exposure slider is moved.
Adjusting Exposure using the NegaFix
Control Panel
The above steps (1 to 5) are designed to ensure that the optimum
dynamic range of the negative has been captured and converted into a
positive. Now it's simply a matter of applying (6) the Auto Adjust
tool  from
the Adjustments Toolbar and SilverFast will complete
the optimisation process. At this point we can simply press the scan
button or make further adjustments to saturation, etc.
Fine Tuning the Image and Film Profile
Curves
Step 6 - Expert mode
NegaFix with SilverFast Ai and HDR
will enable
the user to scan virtually any negative film so that they obtain the
maximum dynamic range along with accurate colour rendering. In
my view the
new NegaFix
feature is a substantial improvement over its predecessor and is
comparatively easy to use.
The screenshot below shows the
control panel in its Expert configuration. To gain access
to the Expert panel we simply mouse click the Tutor Icon,
which is just to the right of the exposure slider.
NegaFix Control
Panel - Expert Configuration
From the Expert panel we can adjust the characteristics
of the "orange mask" removal filter by dragging
the Auto Tolerance slider (green circle in screen capture)
back and forth. Likewise the Highlight and Shadow (end)
points on the histogram can be adjusted by dragging the slider
"bars" located on the greyscale gradients. The check
mark adjacent to the Auto button will be deactivated once
we make any adjustment to the "end-point" sliders. If we
don't like what we've done a simply click of the Reset
button followed by the Auto button and everything is reset
to back to the characteristics of the original film profile.
Step 7 - Creating New Film Profiles
If we want to refine the film curve characteristics or if the film we are scanning is not
included within the list of 120 film profiles it's a simple
matter of adjusting one of the existing profiles in "real-time"
so that we get the desired results. As mentioned above, manually
adjusting the end-points of
the histogram is used to eliminate the effects of the "orange mask".
To further refine the film profile, simply choose the Curves
tab followed by the two icons circled in red and then start
dragging the curve anchor points around until the desired
result is obtained. It is even possible to adjust each of the
RGB colour channels individually.
NegaFix Control
Panel - Custom Film Profile
If an area of the image shows a colour or cast that we
know to be incorrect we can neutralise this cast by simply
clicking that point in the Image preview screen and then
dragging to the baseline; the small dot on the Curves
Gradient (HSL dialog below the curves) that represents the actual colour of the
image
point - see the red circle and arrow on screenshot below.
NegaFix Control
Panel - Colourcast Removal
To reduce the saturation of a particular colour it's simply a
matter of clicking the over saturated colour within the image with
the mouse and again dragging the little dot in the HSL dialog down
a little. To increase saturation we drag it up towards the top of
the HSL dialog. Ideally when undertaking such an adjustment it is
best to zoom into the HSL dialog using the little "+" sign to the
right of the gradient. Be warned that this approach will effect
all subsequent images that use this film profile and so I recommend using
the Hue/Saturation control to be found within the main toolbar.
Adjusting the Saturation
When we are satisfied with the new
profile we simply save it with the appropriate film name thus
keeping it for future use.
Save Edited Film Profile
Give the Edited Film
Profile a Name
Once the dynamic range of the film has been optimised we can
again proceed to use SilverFast's other colour correction
tools in the normal way. Usually clicking the SilverFast Auto Adjustment
button (circled red below) is all that is required.
SilverFast -
Adjustment Toolbar
The SilverFast user manual contain lots
of information and useful tips to using NegaFix
I recommend that you read this section of the manual before attempting
to manipulate the existing film curves.
The remaining pages of this tutorial discuss some of SilverFast's
more advanced colour and tone adjustment tools in more detail.
Step 8 - Removing the last vestiges of the
global colourcast
Overview of SilverFast Ai and HDR
Adjustment Tool Palette
Many of the basic colour and
tone correction tools were discussed in the SilverFast HDR
tutorial, however, I
avoided going into any detail regarding the global
colour
 and
"selective colour" correction tools. In this tutorial I will concentrate
upon the "global colour"
correction, you can spend some time yourself learning about "selective
colour" correction.
To access the "Global
Colour" correction dialog simply press the
 button,
the dialog shown below appears. This tool is designed to allow the user
to alter the overall colour balance of an image.
For now I will ignore the
top row of LED's and digits. All we need look at are the sliders, the
colour wheel and the small vertical slider (green X) shown middle
right. Pull the small slider to the bottom, this means colour correction
is on finest control, big movements still mean small changes to colour.
SilverFast
"Global Colour Correction" dialog
Most users will
automatically go for the 3 sliders and make the corrections by pulling
one or other left/right as appropriate. However, a quicker and much more
effective way is to use the colour wheel. Grabbing the "centre
dot" and dragging it around the wheel cause the overall image
to change, but look at the sliders, all three automatically moved. I
dragged the centre dot towards yellow to reduce the overall blue cast,
but see that some red and green were added by the system.
Colour
correction using the colour wheel
There is really no single
way to use this tool. It is extremely powerful and you should make use
of all its functions. I have only just scratched the surface; maybe
even enough to make you to try it yourself. Further guidance on basic
image editing in SilverFast can be found HERE!
|
