Hi all, My opinion on film flatness has been explained before, so this will be my final word on the topic. I've worked in very high end darkrooms for 20 years, typically making 4 foot to 6 foot prints (110 to 180cm) every day, from 35mm and medium format negs. That is an enlargement factor of 5000%. I have the brightest enlarger heads for these formats - 1000W of halogen lamps, BUT.. I still have problems with film flatness. Brighter light sources make no difference - you simply have to use a glass film holder for this type of high quality work to get edge to edge film flatness.. there is no other way, and there has been no real alternative in 100 years of darkroom technique/ equipment. Now a regular home enthusiast with a small enlarger won't use a glass holder because they don't look so closely at detail corner sharpness plus typically they stop down too much (enlarger lenses are at their optimum 2 stops down, any more degrades the resolution) to get the depth of field/ corner sharpness, which masks any uneveness of film. Or perhaps their lenses are not as wide in aperture to begin with. My point is that the higher your demands get, the more you notice things like film flatness becoming critical. Cheap scanners, or low resolution scanners, like cheap enlargers, dont show the best from the film, but neither do they show the faults in the technique, such as absolutely flat film. it's a good compromise - a stopped down aperture masks a lot of alignment issues that look good up to a point but ask for resolution beyond that point, and the problems begin. I think this is what we are coming across with the new high end prosumer scanners. If you want the ultimate - a 4000 dpi scan, with edge to edge sharpness, then you may have to accept that you need to use glass holders or take other measures to ensure flat film. My point has always been that it is wrong to expect ultimate resolution corner to corner by just dropping a strip of film in a holder and pressing 'scan'. Nobody in the pro-scanning world of drum scanners does that or gets that. Nobody in professional darkroom work does that or gets that. So lets get realistic here... Maybe, just maybe, Nikons approach has been to use a light source that requires a wider lens aperture, gaining very high resolution (they come top in most critical resolution tests) and long term colour stability. Polaroid have taken a different path, used a different (brighter) light source, a smaller aperture and gained depth of field, trading off against ultimate resolution. Nikon make and sell glass holders for their scanners, so... You pay your money and you makes your choice...
paul
