----- Original Message ----- From: "Delano Mireles" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, October 19, 2001 12:43 PM Subject: Pushing and Pulling film
> Could someone provide a concise and clear explanation on the meaning of > these terms and how you would use them to provide different results? Maybe. The term pushing is given to a process of extended from normal development to attempt to compensate for under exposure. The idea is that since an underexposed emulsion will not develop as much density as required with standard development, extending the development will increase the density to a useful level. The problem with this is that when the manufacturer sets the films speed point, it is set at the minimum amount of exposure required to give a usable image. By definition, giving less exposure will result in a less than optimal image. Shadow detail that is lost to underexposure cannot be regained via extended development. Having said that, some films have characteristic curves that tolerate underexposure better than others. Tri-X Pan, with its very long toe is one such film. Push processing C-41 film does not work at all. Anyone who says otherwise is fooling themselves. The C-41 process is a develop to completion process, and any additional development merely adds to the base density. And yes, I have proven this. The now discontinued Kodak PJ800 film was designed to be pushable (according to Kodak, anyway). If you have a look at: http://www.komkon.org/~wrobb/PJ800/index.html (please note, this page is over 500kb, and the server seems a bit slow at the moment.) paying particular attention to the grey scale, you will see that as the film received less exposure, shadow detail was definitely lost. I followed Kodiaks recommendations for push processing, so the results are true. I have heard that E-6 films have better response to pushing, but I have no experience in that regard. Pull processing is exactly the opposite of pushing. The film is given less development than normal to attempt to compensate for over exposure. Again, it doesn't work with C-41, because the mask layer doesn't get full development, and this introduces cross curves and all sorts of ugly colour problems. Also, since the image is formed by translucent dyes, over exposure is less of a problem. Very few C-41 films will block up to the point of unusability with moderate (4 stops or less) over exposure. Black and white films will respond to pull processing with fairly good results. This is an area where T-Max films are great. They have a very long, straight curve, so under development can be used to compensate quite successfully. Since conventional black and white images are formed by opaque silver grains, it is important to not overexpose by too much, or the film will block up the highlights. Pull processing will cure this by restraining development in the highlights. Many Zone System photographers routinely use a speed point several stops below the manufacturers recommendation with the intention of pull processing. This ensures that the very important shadow details are secured, while at the same time ensuring that highlights are not blown out. In fact, this is really what the Zone System is about. E-6 films will also respond fairly well to some pull processing, and since over exposure is a good way to ruin an E-6 film, pull processing is always preferable to standard processing with E-6 film that has knowingly been overexposed William Robb - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
