These are the major points of my current workflow...
I scan to preserve the highlights, although I don't worry too much
about small, bright reflections. I do this by using the "exposure"
controls in the scanner software - I've found that all the other
adjustments are best left to Photoshop. Using the preview, I adjust
each channel's exposure separately to give a reasonably neutral white-
point, with that point as close as I can get to 255 (I'll often use
250 because the preview is quite low in resolution). The image will
usually look a bit dark at this stage.
Crop any borders off the scan before you start processing, as they'll
affect the histogram.
In Photoshop, I place the black and white points at standard values
(about 5-10 for black, I'm flexible for white). I also make the
black and white points neutral. I do this with a Curves layer, using
the histogram as a reference. I have the histogram in the "all
channels" view, at the larger size. As you move the mouse over the
relevant histogram, you can see the current value at that position:
keep adjusting until the lowest/highest values for each channel are
in the desired locations (make sure "preview" is checked in the
Curves dialog, so the histograms will update as you make adjustments).
That almost completely solved my colour correction difficulties. My
scanner setup gives a reddish cast in shadow areas, and I also
remember sometimes getting slight green casts in the highlights.
Sometimes this won't quite work, and I need to modify the adjustments
by eye, often by sampling areas from the image (usually for the
highlights), but film grain can cause problems with the sampling,
even with it set to 5x5 averaging. I usually only have to adjust the
blue channel this way, especially if I'd used E100SW. This will also
be affected by atmospheric conditions (smoke, haze, whatever) on the
day I shot, so white doesn't always look white.
I re-open the Curves dialog and add whatever adjustments are
necessary to make the picture look nice - usually a simple
brightening will do it, but I often need to add a little contrast in
certain areas as well. I usually end up squashing the highlights a
bit, which also helps to reduce colour casts in grey skies by
reducing the contrast. Unfortunately it has the side-effect of
reducing the highlight detail, so I sometimes need to be careful.
The best way to make this process as frustrating as possible is to
place the slide on a small light box near your computer. You will go
mad trying to reproduce the contrast, saturation and shadow detail
visible in the slide. But it does make a good reference for your
adjustments.
Sometimes I'll also need to depart a bit from the slide itself - one
in particular had a bit of a colour cast due to atmospheric
conditions, which looked OK on the slide but was pretty horrible on
the screen.
Please note that most of my slides have well-defined neutral
highlights and shadows. I occasionally scan slides that don't... in
some cases that can be frustrating but for other pics a small colour
offset doesn't seem to matter.
The time it takes me to do all this varies a bit from slide to
slide. I'm generally able to process a dozen 35mm slides in a couple
of hours [not including scanning], largely because dICE does most of
the hard word for me :) For medium format, I'm using a glass holder
and dICE doesn't seem to work very well at the top & bottom edges, so
dust-spotting takes a while. Combined with the extra filesize, I'll
do maybe 4 in the same length of time. The workflow speed is quite
important for me, as I have something like 1,000 slides to scan
before I start on the negs. When I started this scanning project I
was only able to scan & process four 35mm slides in a day (scan in
the afternoon, process in the evening).
- Dave
On May 6, 2006, at 2:51 AM, Markus Maurer wrote:
Hi David
what exactly is different now in your scanning technique?
Since I have to scan a lot ..... I love to learn ;-)
greetings
Markus
AFAIK the newest films were formulated to scan better than the older
ones. I'm going through my archives at the moment and I'm currently
doing a mix of E100SW, Velvia and Provia 100F films that were shot
about 5 years ago. At the start I was having all sorts of problems,
particularly in the highlights. Now that I've improved my
technique,
I'm finding that they all scan pretty well (I'm still glad that I
didn't shoot much Velvia).
- Dave
