Right - ladies and gentlemen, More information.
Analysis of results obtained in the push process experiment with Solaris FG400 film. I'll keep this simple and non-technical as far as possible. It would take some pages to give all the details. The scanner was not calibrated, I have no means of doing this. But direct comparisons between the different exposures are possible - and valid. The negatives were analysed using Scion Image. The results are interesting and support the contention that the speed of FG400 can be increased by increasing development time. The pictures I uploaded to my website yesterday have been replaced with others and include density plots for three frames. http://personal.inet.fi/cool/don.williams/hold/index.htm The plots were made on the red channel. For certain technical reasons it is impossible to scan all the channels at once. The others give similar results. Unfortunately Scion Image scales the Y axis and so one needs to look at the values. The scanning range is 1 to 256 grey levels and was done on a line, one pixel wide, through the centre of the negative horizontally. Frame plot01n 1/125/f 8 density range - 104 to 253 Frame plot02n 1/250/f 8 density range - 51 to 246 Frame plot03n 1/500/f 8 density range - 30 to 231 The first negative is so dense* that it would be very difficult if not impossible to obtain any kind of print. While some parts of the second negative might be printable detail is missing in the denser parts. The third negative, exposed at 1/500 at f 8 is good and will produce a good print. * Over-exposed or over-developed whichever you like. To me these results mean that it is possible to change the behaviour (speed) of this film from 400 to 1600 ASA by increasing development time by 20% with satisfactory results. Don Dr E D F Williams http://personal.inet.fi/cool/don.williams Author's Web Site and Photo Gallery Updated: March 30, 2002 - 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 .
