Kodachrome "Diapositiv" Slide Scanning - Colour Seems Fine

[Peter D]

I scanned some of my Kodachrome slides, processed in Germany in 1981, (see
http://www.dolman.ca/pics/) and they seem fine. I don't see any of the
colour distortions I've heard about. They do seem a bit 'flat' but that
could be because I need to tweak the scanner settings -- I just left them at
the default 200dpi 300% size. The examples are the resulting TIFs converted
to JPG.

Does this mean that this slide film isn't the one that produces bad results?

Also, the slides are in cardboard mounts and the scanner doesn't seem to
crop properly, but is it best to leave them in the cardboard mounts and
manually adjust the cropping? I also have some in glass and some in plastic
mounts. The glass mounts and some of the pastic mounts are thicker. Is is
best to remove them from these mounts and use thinner ones or will it work
just as well?

The scanner is an HP Scanjet 4070. Not the greatest (max 240x2400 optical),
but good enough for testing and for now.

 

[Don]

I scanned some of my Kodachrome slides, processed in Germany in 1981, (see
http://www.dolman.ca/pics/) and they seem fine. I don't see any of the
colour distortions I've heard about. They do seem a bit 'flat' but that
could be because I need to tweak the scanner settings -- I just left them at
the default 200dpi 300% size. The examples are the resulting TIFs converted
to JPG.

Does this mean that this slide film isn't the one that produces bad results?

It really depends on a number of factors:

- Type of scanner. Some light sources (Nikon's LEDs) are more
"sensitive" to Kodachrome than other (conventional) light sources.
- "Seem fine" is a subjective statement. Nothing wrong with that, of
course, if you're getting the results you want. However, it's hard to
quantify that without additional information.
- JPG is not a very good way of evaluating results because it's lossy.
etc.

Regarding slides being "flat" (I haven't had a look, I hasten to add)
but, usually, increasing contrast should fix that. First, make sure
the white point is set correctly (the highlights touch the right side
of the histogram but don't clip - too much) and then adjust the black
point (set it to start of image data at the left side of the histogram
without clipping - too much).

Finally, apply the "S" curve by setting a point in the middle (at 127
or 128) and then two more points around the middle of each half (about
64 and 196). Then move the point at 64 a bit down, and the point at
196 a bit up. This should darken the shadows and brighten up the
highlights resulting in a "peppy" image.

Also, the slides are in cardboard mounts and the scanner doesn't seem to
crop properly, but is it best to leave them in the cardboard mounts and
manually adjust the cropping?

It depends on what you want. The easiest is to leave them in and crop
manually. On the other hand, cardboard mounts in particular obscure
quite a bit of the image, so taking them out will have the added
benefit of revealing this data. Of course, you have to use appropriate
mounts or scan using the film holder.

I also have some in glass and some in plastic
mounts. The glass mounts and some of the pastic mounts are thicker. Is is
best to remove them from these mounts and use thinner ones or will it work
just as well?

The thickness of the mount doesn't matter. The scanner focuses on the
film.

Glass mounts, however, are not a good idea when scanning for a number
of reasons. You are adding another "obstacle" to the scanning process,
you may experience Newton's rings (faint, rainbow colored circles).
Some glass mounts have a so-called "anti-Newton glass" but that's not
good either. Such glass usually has a "rough" surface which will
confuse many scanners when focusing, and also produce grainy
appearance. On the third hand ;o) if your slides are curved the glass
will flatten them out. So, it's really up to you do decided what's
more important.

The scanner is an HP Scanjet 4070. Not the greatest (max 240x2400 optical),
but good enough for testing and for now.

Oh, a flatbed... They are not the best for scanning film for a number
of reasons. I thought you were using a film scanner. Still, most of
the above does apply.

Don.