Dave said:
Can anybody give me some advice on film scanner settings? I'm about
to start a big project and I want to do it right.
I have a Nikon Coolscan IV ED film scanner, NikonScan 4 software, an
old, crummy computer monitor, and about 1500 35mm slides that I want
to digitize before they rot away. My goal is to have all the slides
scanned into my computer and burned onto CDs or DVDs so I can display
slide shows on both my monitor and my TV set.
What settings for resolution, color space, brightness, etc. should I
use on the film scanner so the scanned images will be compatible with
both the monitor and the TV? So far, the images I've scanned look
very, very dark on the monitor even though downloaded and website
images look just fine. Is the problem with the scanner, the software
or my monitor? Is there a set of standard, archival settings for
scanning images that I should use?
The one or two times I've tried to view digital images on my TV set
they didn't look very good at all. Poor resolution and a shimmering
effect. What equipment do I need to make that work?
Taking these one at a time...
Best settings etc. Well its up to you really, however even though your
monitor probably can't display more than 1024x768 pixels and your TV a
measly 640x480 I would scan and archive at the resolution limits of the
scanner. Who knows what display technology you will have in a couple of
years time and you might want to print several images too. Unless you
want to undertake this medium sized task all over again then do it right
the first time. In your case, 2900ppi is the native scanner resolution
and you will get a maximum image size of 4203x2870 pixels with the MA-20
slide holder. Save the high resolution scans in tiff format (definitely
NOT jpeg, which is lossy), which will result in each slide taking up
around 34Mb of disk space if stored at 8bits per channel.
The colorspace I would recommend for archiving is either Adobe RGB(1998)
or RAW. However, to display on your monitor as a web image you will
need to use sRGB, unless you use a MAC, when you should use AppleRGB. To
display on your TV you should use NTSC(1953) colourspace.
Obviously, that means at least three separate versions of the image to
get the optimum, but there are a couple of compromises. You can select
one of these colorspaces and accept that it will not display with the
full saturation or gamut on the other media. Alternatively, since you
probably need three resolutions in any case, archive the slides in Adobe
RGB or raw and then resize and convert them to the required resolution
and colorspace for your monitor and TV using an imaging application like
PS Elements or Photoshop. Store the monitor and TV copies, either on
the same CD as the archives or on a specific CD for each type. You will
need many CDs and/or DVDs to store 1500 slides at full resolution, but
could probably fit most of them on one or two discs for both monitor and
TV display.
Now, getting the optimum scan. First you need to get your monitor set
up pretty well, and there are a couple of web based tools that will
allow you to do this. As a start, open Nikonscan and go to the
Preferences section. Under colour management, switch Nikon Colour
Management off. Then go to Gamma and select the gamma for your system -
PCs use 2.2, Macs use 1.8. Then adjust the brightness (not the
contrast) of the screen until the hashed areas have the same brightness
as the solid greys. When that is done, go back to colour management and
enable Nikon Colour Management, making sure you have the colorspace you
want selected under RGB.
Make sure that you have autoexposure and autofocus switched on under
Preferences|Single scan. If you are going to scan film strips make sure
the same setting is used for Batch scan as well. Take a slide which has
a reasonable amount of pure white and pure black in it and preview that.
The autoexposure should result in a scan which is pretty well exposed
but, to be sure, look carefully at the histogram in the Curves Palette.
The histogram should extend from 0 to 255. If you find that the white
is clipped at a level significantly below 255 then adjust the exposure
and preview again to bring the clipped level closer to that value, but
don't exceed it. If there is a lot of saturation at 255 then adjust the
exposure and preview again. If you notice two or three spikes, look at
the histograms of the individual colours and adjust the exposure for
these colours accordingly to get something close to 255 in each one.
Having achieved a reasonable exposure, select an area of the preview
using the crop tool which includes most of the image (certainly the near
black and white areas) but none of the slide mount. Then return to the
curves window and click on the autocontrast icon (circle with half
white, half black) and this should return the curves window
automatically to the RGB view and adjust the histogram levels to almost
exactly the full 0 to 255 range. However you might want to adjust
manually the upper and lower ranges in each colour to reduce the slight
clipping that inevitably results. The idea is to get the black and
white points set to exactly where black and white lie in the image.
Having done all of that, select your crop to exactly the area you want
for all future scans, and select the ICE, GEM & ROC setting you desire,
together with 8-bit depth. Save the setting under the "Settings" menu
to a name you will remember and also "Set User Settings", which will
save these settings as your defaults for subsequent scans.
That should get you pretty close to optimum scans, so try a couple of
images to begin with. If there is a slight residual colour cast, then
look for an area that you know is neutral mid-grey in an image and use
the grey dropper in the Curves Palette to select it in the preview. This
should take out any "slope variation" in the film dye transmission that
might exist between the broad spectrum that your eyes see and the narrow
spectrum that the LEDs see. When you are happy, save the setting and
Set User Setting.
You should be ready to go for 1500 scans now, but depending on what mix
of film and age they are you might need to revisit the settings and save
new settings for specific films. Remember to use the Kodachrome setting
if you are using KC emulsion - which will almost certainly require fine
adjustment of the Curves for every batch of film. You might also
experiment with the other settings for colour balance or saturation
(chroma in the LCH palette), and Unsharp Mask, but to be honest you
shouldn't need to adjust these at all, particularly fro your archive
scans.
Good luck.
