ok , films are physical entities unless rendered purely on CGI or shot with a digital camera (like Sin City and Corpses Bride at HDTV resolutions)
Film is light sensitive silver grains that turn black or colored dyes clouds replacing them (for colour film
) suspended in a gelatin coated onto a hard base. Like nitrate base in the "olden times" as you mentioned and current safety film after the 50's and even harder polyester ("Estar" base)
Since they're physical things they're prone to physical deterioration and external element damage.
Physical imAge deterioration is the result of light, heat, humidity, chemicals in the air (pollution), and chemicals carried over from the developing process that migfht not been totally stabilized or cleaned. (archival processing)
External elment damage could be dust and scratches and tears, mishandling etc.
Or even putting recently discovered unique surviving elements that were lost for 40 years and then found, thru a "rejuvenating process" that subsequentlty damaged it in a couple of years. like the uncut print of the Alamo
As years go by, the base can deteriotate (for example Nitrate base can even spontaneously burst into flame!) , the safety film shrink and yellow, and the color dyes in the emulsion fade (they're kinda organic stuff
) (Silver since its metal, don't fade, so b/w images ussually don't dissapear
)
All this changes can be retarted by clean chemical processing in the first place when developing the negatives, and subsequent proper cold dark dry storage.
And of course dust can accumulate and scratches accumulate when the negatives are handled.
To completely arrest this deterioration films would have to be frozen or something permanently. But with proper care things could last hundreds of years. The problem is that sometimes (often??
) films are not properly cared for. But there's no reason for a properly stored (emphasis on properly) Silent film negative or print from the 19th century to look as good as it did back then. The thing is sometimes they don't discover the improper storage till its already deteriorating por too late.
Nobody thought about Blu-ray home video profits in the 21rst cenrtury back then
Flecks and artifacts must refer to dust scratches and all the detritus that shows up on prints that may have acumulated over the years,., this can be cleaned physicaly sometimes but if embedded on the emulsion, then only "digital image restoration" can get rid of it.
Now about graininess, as photographic film images are created by grains of silver all film images have grain if you look at them close enough. Depending on the film emulsion and the negative size the film may apear grainy or grainless at normal viewing distances ( which i consider to be around 1.5x the picture height for theatrical movies
) (hey i'm wAtching a movie not a home video
)
graininess don't increase after time, it's fixed at the time the negative is created. What happens on prints and home video transfers is they could use a copy or a copy of a copy or a copy of a copy of a copy of the negative etc etc and each copy adds its own grain to the image . All prints are COPIES with more grain than the negative (as they have the negative grain PLUS the print grain) unless youre watching a Kodachrome (positive transparency slide emulsion) film and mmmm thats not Hollywood films
Most prints these days are even 3rd and 4th copies as in:
Negative --> Interpositive --> Internegative --> Theatrical Print
old film prints might been done directly from the negative so that's one reason the negative is damaged.
Video transfers should try to use ther earliest element posible but they don't always do it cus they don't have it or they don't wanna risk the original precious negative no more.
Now apart from grainy sources, why graiuny DVDs? could be they overcrank the sharpness and the grain is put more clearly in relief.
I still think a properly made DVD from a 35mm original negative should be almost grainless (if the directors intentions wasn't to add a grainy look on purpose that is
) cus DVDs at 480 pixels per picture height have very little resolving power to resolve grains that make up 2000 line images or smaller!
(a line (or detail) on a film is made up of several smaller grains clumped toguether creating it
)
In any case the graininess is inherrently part of the image on the original negative, a nescessary evil for some an aestetic quality for others so even animated films (not done on a computer of course) might have grain, the question is how much, and of course in these days of digital image manipulation another question shows up, should we leave the slight negative grain in, clean it up just a little, or in some cases (like film cel art) eliminate them totally?
Usually original camera negatives have little grain visible at normal viewing distances and again the resolving power of the video (be it 480 DVD or even1080 Blu-ray) might even merge the visibility of the individual grains into less than what's on the film (if you have specks of grain forming the image that are 1/2000th or smaler in size making a 1000 line image, they would be fainter on even a 1000 line High Def transfer while the 1000 line actual image would come thru fine and strong. You'd probably need a 2000 pixel tall scan or higher to get all the grain even tho you might not get much more detail in the actual image for example)
Now about actually visibly degraded film video transfers:
if a film is faded (usualy color films) you have to either opticaly make a increased contrast dupe, or on the other end of the technology spectrum a digital version with contrast altered digitally. (There's a couple other methods to do it in between those two) Sometimes a combination of methods is used.
These things are costly and they can give excellent results sometimes and not so hot in other ocassions, but if that's what survives of the movie (theres lots of movies that have their negatives destroyed or totally ruined and even the copies are bad), that's all you get.
depends also in how much money and time you have to restore and the capabilities of modern current technology.
When you increase contrast, or push color, for example, you do it at the expense of increasing visible noise, or "grain" if you will, and any scratches and dirt in the film will be magnified etc .
So I assume that somehow the films degrade and Disney is either lazy or no money to "restore" them. Further, do films constantly have to be restored even if they are modern films done on modern film medium?
As you can see the answer is in a sense yes they degrade even in modern stock if not properly stored. But no they dont have to restore them constantly, if they take measures, in fact i think we're almost to the verge where you can scan all film elements at 4k (4000 pixels across the width) or sometimes more, and save a kind of digital copy and use that and preserve the original negative from now on. When they "restore" a video, it means they didnt do it (transfer it) completely right the first time and this time they're supposedly doing it better or with better elements, or worse of worst, they're even altering it to make it look different
) (like many "remastered" CDs today that sound different (and worse) that older CDs or Lps done correcty back then
)
Now about Disney films, most Disney animated classics and shorts are kinda little different case than most movies cus they were shot in the Technicolor Sequential Process so that means they were shot in tricolor
B/W film separations and as i said b/w film doesn't fade. So all this modern restorations what they ussually do as opposed to old "non restored" video transfers is make the transfers hopefully from these fairly well kept b/w tricolor separtations into RGB computer color and with higher resolution scans that are then downrezed into video sizes for DVD and we get the full original brilliance
TM, while older transfers might had been done in normal resolution video equipment from prints and internegatives (and prone to fading) done a long time ago from the original Technicolor elements at some point in their "ancient" history.
theres also a side note that the Technicolor process had two parts, one was the camera shooting into three b/w negatives, and the second part, that were technicolor prints made from them with pure dyes that dont fade in a process similar to printing a magazine. In the 50's hollywood stopped shoting color films like that (but not Disney! cus he had the Technicolor Sequential Camera) and subsequently used the current type of 'color in one' negative (the kind you buy in Walgreens) (which fades) but kept making printing films in Technicolor for several films and was latter in the 70's they stopped printing that way and started using the 'color in one' fading prints exclusively (Disney also did the prints this way after that) and at one point the Tech b/w negatives musta been copied onto 'color in one' imternegatives for easy printing, and thus this all was before home video. In fact it was almost the same year BEta and VHS appeared. And TV stations and video houses got then prints made that way from then on.
The End
(for example I have 4 differenmt Wizard oF Oz sourced videos: Tech print aparently made specially for NTSC TV, Technicolor theatrical print, Color Interpositive made from Technicolor b/w separations, and now the new Ultra Resolution transfer made from the b/w elements .)
So hope this explains a little why video transfers are not always perfect and films have to be restored sometimes.
Of course many transfers could be bad cus they don't do them right
Cause I was just trying to make deathie-speak more user-friendly, lol.
All you have to do is search like half of deathie's posts, it's an encyclopedia, lol.