Transparency vs neg for scanning?

From a general quality perspective, will I get better results scanning slides or negatives into digital format?

I would like to shoot either slide or neg and when processed have them scanned directly to CD rather than print them.

I also have many old slides and negs that I want to manipulate with PS and print on a home printer. Is one superior to the other?

Scanners, especially those at the affordable end of the spectrum, have a limited range of luminance values that they can sense. Slides are designed for direct viewing, and so spread their luminance range out to make it look real when projected. Thus, slides often have values that fall outside the dynamic range of affordable scanners.

Negatives, on the other hand, actually record a much higher range of scenery values, but they compress them into a narrow range on the film. This narrow range falls within the scanner's dynamic range in most cases, unless the negatives are really overexposed. If you scan with enough bits in each pixel, you can spread those values back out for your prints, and you can spread them where you want to spread them. I have pulled up enormous shadow detail from negatives scanned in a cheap scanner--detail that the lab proofs had turned to solid black.

In photographic terms, slide films have a photographic range of about five or six stops (some are even less). Negative films have a photographic range of perhaps 9 or even 10 stops. The slides take those five stops of scenery values, and spread them out to 10 or 11 "stops" so that it will look real on the slide. This is why slides are so dynamic. Negatives take record their 9 stops of scenery values onto about seven "stops" of density values. I put "stops" in quotes because I really mean "zones" as used in the Zone System, where black (opaque on slide film) is Zone 0 and paper white (clear on slide film) is Zone 10, with the nine zones in between being nominally one stop of exposure apart.

Good but affordable film scanners have a dynamic range of density values from about 0.6 to about 3.6, which is 10 "stops" on the logarithmic scale used by those density measurements. Thus, high-contrast slide films will hang a stop or two over one end or the other of that range, while negatives will fit within it.

Therefore, for scanning, I always use negatives. But that doesn't mean I'm not willing to scan old slides, of which I have thousands. I just realize that I might not get all the tonal information that is in the slide. I'd have to make the same choices if I made a print from those slides, because print materials are even more limited than scanners.

A good site for explaining this in even more detail is http://www.scantips.co​m.

Rick "who now owns a 10D but who does most of his work in medium format subsequently scanned" Denney

Either will give as much information with proper scanning techniques. I am not sure about Rick's information but regardless it depends more on the twain drivers of the scanner than the film type. A good quality scan needs to be set up for a specific film type. The variance among transparency films is very large as well as the variance between negative films. Obviously negative films are designed for creating decent prints over a large range of latitude. Prints need to compress that latitude more than transparencies do.

If you have them scanned by a local lab make sure they have a profile for the specific type of film you are shooting. For low-res Kodak photo-cds you may be better off shooting Kodak film as opposed to other brands. Same goes for higher-res picture cds. If you choose to buy your own scanner check to see that they offer drivers that can recognize a multitude of film stocks and don't just offer generic negative and generic slide settings.