Appears the lab owner's claim is no longer true. In examining both film types, my conclusion was that print film has less grain and the apparent resolution is higher. Your noted exposure variables are, of course, critical to the question. Thanks for your 'complete' answer.
Jack --- Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > This is what my forty years of photography have led > me to understand on > this subject... > > B&W negative emulsions nearly always have better > grain and higher > acutance than any color emulsion at the same ASA > rating. B&W Processing > is extremely variable and plastic, however, so it's > hard to make hard > and fast generalizations. > > The biggest influence on grain structure in color > emulsions is > exposure, given stable, calibrated machine > processing. Negative films > are sensitive to UNDERexposure and tend to produce > grainy results when > underexposed. Transparency films are sensitive to > OVERexposure and tend > to go clear when overexposed. This creates the > illusion that negative > films are grainier than transparency films, since > most people tend to > underexpose film, which leads to richer, more > saturated, less grainy > results in transparencies. Given proper exposure ... > > Positive color emulsions up to ASA 100 had lower > grain and higher > acutance than Negative color emulsions in the same > speed range until > the early 1980s. Higher speed color films, both neg > and pos, pretty > much all sucked when it came to grain until that > point, and forget > about acutance... > > Then the first generation of T-grain emulsion films > were introduced in > color negative. These immediately proved lower grain > at the same ASA > ratings and made huge improvements in color > saturation and acutance ... > ASA 200 and 400 were now usable. It took a while for > T-grain technology > to move to transparency film due to the more complex > emulsion structure > of transparencies, but this has brought transparency > films closer to > but not on par with negative films. The thicker, 6-7 > emulsion layer > construction of color transparency film works > against it on acutance; > grain is about the same given the same ASA and > proper exposure with > today's films. > > (In the couple of decades since T-grain technology > was introduced, > color films have come a long way. But their > development has been very > slow in the past decade: emulsion technology seem to > have reached a > plateau where substantial improvement is either not > needed or no longer > sufficiently profitable to fund the R&D required. > The film > manufacturers continue to tweak their formulations > and drive small > gains, but big leaps like T-grain and C41 process > B&W film are likely > at an end, for the moment at least.) > > Godfrey > > > On Apr 8, 2005, at 10:35 AM, Tom C wrote: > > > Back when I paid attention to this, the answer was > generally yes, > > IIRC. Positive films tended to have finer grain > than negative films. > > Comparing Kodak and Fuji was like apples and > oranges because Kodak > > measured their grain and differently than everyone > else. That made me > > suspect, and I in general shoot Velvia 50 or > Provia 100F. Back when I > > last checked, they were the finest grain films > available. > > > > Caveat... I'm remembering back over 5 years ago. > Sorry, I can't > > provide any info for B&W. > > > > Tom C. > > > > > > > >> From: Jack Davis <[EMAIL PROTECTED]> > >> Reply-To: [email protected] > >> To: [email protected] > >> Subject: Pos vs neg grain > >> Date: Fri, 8 Apr 2005 09:24:20 -0700 (PDT) > >> > >> I had a lab owner emphatically contend > that.."positive > >> film of the same ISO has finer grain than > negative > >> film". Didn't address b&w. > >> We happened to be reviewing a b&w print at the > time > >> and their existed a situation wherein the subject > >> couldn't be pursued (customers waiting). > >> I've since emailed him for a follow-up on his > >> recommendation that "b&w film be scanned as > positive > >> film". > >> If his answer (if received) is at all > decipherable, > >> I'll forward it. > >> Does anyone know or suspect what he may be > talking > >> about? > >> I've, also, read the RMS charts but, their > results > >> don't appear to be comparable. > >> > >> > >> > >> > __________________________________________________ > >> Do You Yahoo!? > >> Tired of spam? Yahoo! Mail has the best spam > protection around > >> http://mail.yahoo.com > >> > > > > > > __________________________________ Do you Yahoo!? Yahoo! Personals - Better first dates. More second dates. http://personals.yahoo.com
