I understand the behavior of VC paper, but my comments intended to deal with the fact that the tonal range of brightly lit scenes exceeded the tonal range of any paper. "Ratcheting down" the exposure time in such situations would bring the highlights more into the tonal range of the paper, at the cost of shadow detail, advantage being that you at least don't lose both highlights and shadow. Thanks for your thoughts. ----- Original Message ----- From: "Guy Glorieux" <guy.glori...@sympatico.ca> To: <pinhole-discussion@p at ???????> Sent: Friday, July 12, 2002 8:05 AM Subject: Re: [pinhole-discussion] Why is paper "contrasty"?
> William, > > If you go to the Ilford web site, on the B&W products page, > http://www.ilford.com/html/us_english/bw.html > you will find hiding somewhere towards the center of the page an Acrobat > document called "CONTRAST CONTROL" that deals with your question. > > Basically, contrast on B&W variable-contrast paper is determined by the > amount of blue that hits the paper. Under the enlarger, low contrast is > achieved by reducing the amount of blue from the enlarger lamp with a > yellow filter. > > VC paper is calibrated for tungsten, which is yellow in color, compared > to daylight which is much more blue. So, it's only natural that paper > exposed to "blue" daylight will be more contrasty. > > To reduce contrast, use a yellow filter similar to the 00 that you would > use under the enlarger for minimum contrast: it works very well. It > will block some light, compared to not using a filter. But, if you use > Ilford paper, its speed is higher at lower contrast grades than at > higher contrast. As for me, I use ISO 4 when I shoot paper negatives > and it works well for me. > > Hope this helps, > > Guy > > ----- Original Message ----- > From: "William Erickson" <erick...@hickorytech.net> > To: "ppinhole discussion" <pinhole-discussion@p at ???????> > Sent: Thursday, July 11, 2002 8:45 PM > Subject: [pinhole-discussion] Why is paper "contrasty"? > > > > I've thought this through but haven't completely verified it yet, but > I > > wanted to see what others reaction is. B&W paper used as a negative is > said > > to be "contrasty". What does this mean? B&W paper has a sensitivity > range of > > a little more than four stops for any given exposure. Burning and > dodging > > increase tonal range by shortening or lengthening the exposure. If you > meter > > a scene that has an eight stop tonal range and give the average > exposure for > > the scene using a paper negative, you risk having the highlights blown > out > > because they are more than two stops above average, and shadows go > black > > because they are more than two stops below average. If the scene has a > tonal > > range of only four or five stops, your negative won't be contrasty > because > > all the tones lie within the range of the paper. What, then, to do in > > sunshiney scenes, for instance, where the tonal range might be eight > or nine > > stops? If you place the highlight tones of the main object of your > > composition about two stops above average, you will get good tonality > in > > important spots, no blown out highlights, even though you may get lots > of > > black shadows. The implication is, much shorter exposure times (read > higher > > ISO) in bright scenes than in shadowiy scenes (effctively lower ISO), > using > > the same paper. My first tests suggest that a good ISO for Ilford > multigrade > > in bright sunlight might be as high as 15, while 5 works well in > shaded > > scenes. Any comments? > > > > > > > > _______________________________________________ > > Post to the list as PLAIN TEXT only - no HTML > > Pinhole-Discussion mailing list > > Pinhole-Discussion@p at ??????? > > unsubscribe or change your account at > > http://www.???????/discussion/ > > > _______________________________________________ > Post to the list as PLAIN TEXT only - no HTML > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??????? > unsubscribe or change your account at > http://www.???????/discussion/ > >
