Richard K, I finished the roll of ADOX 100 ASA. I did several shots in the gardens in front of my apt, a couple of the cat, etc. I got lucky, I have inherited the GRAFLEX, but also a CHICAGO MAJESTIC tripod and head that I use with it for it's extreme stability. I will be developing it in a few hours or so. On 3/22/08, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote: > > > ----- Original Message ----- > From: "mail1" <mail1@xxxxxxxxxxxxxxxxx> > To: <pure-silver@xxxxxxxxxxxxx> > > Sent: Friday, March 21, 2008 10:26 PM > Subject: [pure-silver] Re: Kodak vs Ilford > > > > > Richard, Your comments on film curves verses film types is > > excellent. > > > > > Thank you:-) > I didn't talk about the shoulder because most modern > films don't really have a shoulder until they reach > impractical densities. Most B&W films have an enormous > overexposure latitude, six to 10 stops in many cases. This > is not the _range_ of the film but the amount the exposure > can be increased from the ISO exposure and still have good > tone rendition. > I suppose I should define a shoulder. Just as the film > has a low contrast area for very low exposures (the toe) it > also looses contrast for very high exposures. At some point > the film reaches its maximum density and will just go no > further. The theory books will show an area of reversal for > extremely high exposures but modern films do not seem to > ever reach this point. As the highest densities are reached > the contrast is reduced and this part of the curve is called > the shoulder. > A shoulder can also be produced by the developer. Some > developers just are not active enough to develop the highest > possible densities on the film. If you look at the data > sheets for Kodak films which show development in the > Versamat automatic processor you will find the higher > densities shoulder off at noticably lower densities than > when developed in something like T-Max or even D-76. > It is possible to generate an artificial shoulder by > using what is called a "compensating" developer. These are > highly diluted or otherwise designed to have too low an > activity to reach the highest densities. Also, development > without agitation will result in local exhaustion. In the > dense areas the developer reaction products build up slowing > down development. In normal processing the agitation removes > these reaction products and allows fresh developer to > penetrate the emulsion. Not all developers are equally > sucessful in stagnant development because some reaction > products actually accelerate development rather than > restraining it. A developer containing Metol as the sole > development agent will exhibit compensation and also edge > effects because the reaction products of Metol are > restrainers. Rodinal, which is related to Metol behaves the > same way. The reaction products of hydroquinone, OTOH, are > accelerators and a hydroquinone developer will not show the > same sort of effects from low agitation as one having only > metol in it. > Printing negatives with very high density highlights is > a problem. If the image is not too complex the exposure of > different areas can be adjusted by burning and dodging. To > do this well (so that its not obvious on the final image) is > not too easy and requires a lot of practice. > Local contrast can also be reduced by the use of > contrast masks. These can be made with a contrast higher > than the negative so that they result in a non-linear final > curve. Contrast masks used to be common in color printing > especially with Cibachrome. They are not too difficult to do > for B&W. Similar effects can be gotten from electronic image > editing programs like Photoshop but many are not aware that > they can be generated photographically albeit with more > work. > > A last word on film curves: I think the best explanation > of their effect is in the older Kodak film databooks. I have > no idea where to find these other than camera swap meets or > dealers specializing in this kind of thing. Its possible > some library systems may have them. The edition is not > important because the same text was reprinted with the film > data sheets tipped in. Its the text you want so having > obsolete data sheets is of no consequence. > > > --- > Richard Knoppow > Los Angeles, CA, USA > dickburk@xxxxxxxxxxxxx > > > ============================================================================================================= > To unsubscribe from this list, go to www.freelists.org and logon to your > account (the same e-mail address and password you set-up when you > subscribed,) and unsubscribe from there. > -- I am a leaf on the wind! Watch how I soar. -Hoban "Wash" Washburn (serenity movie) ----------------------------------------------------------------------- http://mcpeak.jason.googlepages.com/home