Archived posting to the Leica Users Group, 2005/11/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On Sun, Nov 20, 2005 at 11:08:08PM -0800, Peter Klein wrote: > There were a lot of miniscule white spots on my Neopan 400 negs from San > Francisco. I don't usually get these, at least not with Tri-X or > T400CN. This picture is a 1:1 snippet of the "vertigo" picture from my SF > gallery, but scanned on my Canon FS-4000us at 4000 dpi. The spots are > most > visible on the windows at the right, but they are actually all over the > whole negative. > http://gallery.leica-users.org/album186/1_25WhiteSpots > > The negs were developed at the same lab I usually use. What is all that > white crud? Grain aliasing? Improper fixing? Chemical residue? Seems > too prevalent to be dust. I couldn't see anything with my 22x loupe. But > I could see many of the same spots both on the low-res Noritsu scans from > the lab, and on a couple of pictures I rescanned myself at 4000 dpi. So > something on the negative is making those spots. > > I know better than to use ICE (FARE actually) with real B&W, so that isn't > it. > I get these spots all the time when scanning HP5 souped in ID-11. My processing is immaculate so I know it's nothing to do with the film or chemicals. I use a Nikon LS-4000 and my guess is that it is the light source of the scanner which is causing the problem. Mine has a collimated light source and shows up stuff that just would never appear when using a diffused light source. Usually, this is exaggerated grain and the "micro-blocking" (don't know what the official technical term is) that you are showing in your image. The problem goes away when I choose another film/dev combo (e.g. Tri-X and DDX) but I'm not willing to give up my standard combo for the sake of getting good scans (I still mostly do wet prints). In short my guess is light source combined with the grain structure of that particular emulsion is the cause. Shows up even more the second you try and do any sharpening. -- Tony Terlecki ajt@mrps.demon.co.uk