ScanCafe in Fishers, IN, is a decent option if you want a commercial service to do it.
https://www.scancafe.comCurrent Pixel in Atlanta, GA, is another one:
https://currentpixel.com A lot of the resulting quality depends on the following:
Film stock β Kodachrome slides are always the least resistant to dye fading, probably followed by Anscochrome and certain Ektachromes. However, most Ektachrome slides lose their yellow dye layer first, then the magenta layer goes. Fujichrome slides from the 1970s fade to pink. 3M slides and Agfachrome slides tend to go red.
Storage conditions β Slides stored in plastic or metal storage boxes, BOXED metal projector cartridges, or BOXED Carousel projector trays tend to be cleanest. Slides in archival
polypropylene album pages are usually in as good a condition. Slides stored in PVC pages may have severe damage from the outgassing of vinyl chloride from that harmful substance. Slides stored in high humidity may have mold damage. Slides stored with dust and grit on them may have it embedded into the base (glossy) side of the film, due to humidity shifts over the years. Scratches on the emulsion side of the film may show up as colored lines or even clear lines. Scratches on the base side of the film show up as black or gray lines.
Exposure and processing β Slide processes were/are all standardized and β in most labs β rigidly controlled. So exposure at the camera determines the density of the slide (how light or dark it is). Don't expect any improvement in digital images made from over- or under-exposed slides. Most commercial services will try to reproduce what is there, rather than adjust for light or dark images (How do they know what the scene looked like, or what the photographer intended?).
Some duplication services will use Digital ICE hardware and software to try to remove dust and scratches. The infrared sensor in an ICE scanner reveals surface imperfections that the software then removes. Unfortunately, that does not work on Kodachrome emulsions, because those are ridged, layered surfaces. It doesn't work on silver emulsion black-and-white negatives, either. It does work on Ektachrome, color negative films, and chromogenic black-and-white films.
Remember that when viewing old film images converted to digital, our perceptions of quality have changed! It is possible to create much better digital images (sharper, cleaner, clearer, more color accurate...) than it ever was with film.
The difference between a $.50 scan and a $5.00 scan is usually
custom finishing β Clean the film, crop for the main subject, straighten the horizon, adjust color, recover highlight and shadow details, set exposure and brightness, remove dust spots, sharpen, etc. There is a lot of dynamic range in film. It can contain information that might be revealed with a careful operator at the controls.
ScanCafe in Fishers, IN, is a decent option if you... (