One of the main advantages of using Negative type film
is the ability to capture a wider dynamic range than can be achieved with
Reversal types (slide/chromes). Unfortunately the image data is
usually compressed into a much smaller density range. The big trade-off
is our inability to immediately see the information due to the orange
mask.
Most film scanners are supplied with software that is capable of
scanning both Reversal and Negative type film. However, not
all scanner software is created equal and some is just plain useless at
scanning negatives. I see little point in using a negative type film only
to have the scanner software trash a fair percentage of the highlight and
shadow detail in an attempt to get a visually pleasing image straight
from the scanner. It's much better to manually tune the image so as to
extract every last "bit" of detail. Needless to say this is easier said
than done - or is it?
The following is a technique used by many who find themselves doing
battle with inadequate scanner software. With care this technique has the
potential to produce results equal and occasionally superior to those
obtained from even the most expensive scanner applications.
23 October 2002 - It has
recently been brought to my attention that some view the technique
discussed below as flawed or at best less - than perfect. The
implication being that other more effective techniques exists. This may
be so, and since I haven't suggested that the technique discussed below
is anything other than an alternative to less than perfect scanning
software - I'm not arguing with them. However, at no time did I suggest
that anyone should consider this technique as their primary method of
scanning colour negatives. The following information should clarify any
settings that may be causing their confusion:
-
You should ensure that any Automatic Exposure systems
within the scanner software are disabled.
-
Ideally the scanner Gamma should be set somewhere between
1.5 and 2
-
The key to success is getting a scan that does NOT clip the
highlight or shadow in ANY colour channel.
If after trying the following method you still get poor scans from
your negatives then you might wish to try VueScan from
http://www.hamrick.com
An Adobe Acrobat version of this tutorial can be downloaded by
clicking the following
logo.
Step 1
Scanned Negative
Step 2
Inverted Negative
Step 3
RGB Channel
Step 4
Red Channel Corrections
Step 5
Green Channel Corrections
Step 6
Adjusting the Blue Channel
Step 7
-
Return to the RGB Channel. If the adjustments
associated with steps 4 to 6 were done correctly you should find that
the RGB Channel histogram is spread out more than the original.
In the example shown below I have managed not to clip Highlight
or Shadows.
-
Adjust the Shadow and Highlight sliders
as required.
The RGB Histogram
The majority if not all colour casts will have been
removed. If they haven't make the necessary adjustments in the normal way
using either Levels, Curves or Colour Balance. For
examples of how this can best be done see
Tutorial 3
Nearly Complete
Step 9
Increase Contrast
Although no master piece the final image is shown below.
Not bad for about 5 minutes work.
The Final Image - Townhouse,
Dublin
