Re: filmscanners: Sprintscan 120 and new negative proile scheme (LONG)

[Arthur Entlich <artistic@ampsc.com>]

Johnny Deadman wrote:


> Do minilabs read the emulsion type before printing neg? No.
> 

I don't know exactly what you mean by "do mini-labs "read" emulsion 
types before printing negs"

If you mean do they read for each subtle change of emulsion a 
manufacturer makes, then your answer is correct.

If you mean do they have a starting point that is based upon the 
emulsion dye base, the answer USED TO BE absolutely.  Our Noritsu unit 
had something like 32 "channels", each one was pre-programmed for a 
specific emulsion dye base.  As new emulsions became available, I 
programmed them myself, if they weren't provided by the manufacturer.

Today, I think newer machines just read the blank film area and make an 
automatic correction. With faster computers and more sophisticated 
software it is no longer really necessary to have a base filter pack 
programmed into the machine for each film type.  That means they do not 
correct for difference responses of the emulsion layers, or 
characteristics of the color balance of the film, but just attempt to 
come up with a "zero" point, so that if you were to make a print for a 
18% grey card, you'd get something approaching a print that looked like 
18% grey.

Unless one considers the sensitivity peculiarities of a specific film as 
a type of defect to be corrected for (all films suffer from their own 
versions of reciprocity errors, as well), then it would be best not to 
correct in complex profile of the film.  Kodak used to offer two 
versions of scans for PCD.  One was a base correction type that did not 
alter for film characteristics.  The other was an averaging type that 
attempted to make all films look the same regardless of the emulsion type.


The reason for this was simple.  For a pro photog who wanted to maintain 
the integrity of the film's characteristics, the base type was good, but 
for a person creating a PCD presentation where they had multiple sources 
(different age, emulsions and film types -including maybe both slides 
and negs) and they wanted some consistency of color throughout the 
presentation, then the second type of scan made more sense.

This is a philosophical issue.  Some photogs simply are after repeatable 
results, and do not want to either play with or emphasize the film 
characteristics, while others want the scan to represent the film image, 
and have chosen (or accidentally) gotten a result that works with the 
specific emulsion characteristics.  I know that sometimes an image has 
been pushed beyond my expectations due to the film doing something I 
wasn't anticipating, making it into a winner, while other times, upon 
reflection, I can look at an image and say "Gee, had I just used 
__________ film instead, this would have been so much nicer."

More often than that, I say "Gee, had I just bracketed that a bit more, 
or had I just waited for the lighting to change a bit more, or had I 
just not used that lens, or that angle or that processor (who put a 
scratch in the middle of it!)..." you get the idea...

Although I haven't gotten to the point where I'm saying "Gee, if I had 
just remembered to recharge the batteries, put film in the camera, to 
remove the lens cap, or worse still, to bring my camera equipment!" I'm 
sure that will eventually happen.

I have had one "gee, if I had just remembered to rewind the film into 
the cassette BEFORE opening the back of the camera, that would have been 
a really good idea (or works "to that effect" ) ;-)

Actually, in case this happens to someone else (I'm SURE I'm the only 
photog who ever did it...) if you do happen to open the back of the 
camera before rewinding the film into the cassette (yes, I know, Canons 
work the other way around)  Quickly slam the camera back shut.  Believe 
it or not.  Film is relatively opaque before processing, and although 
you will lose your last frames and have some edge light fogging, most of 
the frames will likely survive... really!


Art

Art