No, Caveman, you missed the point. I was thinking about colour, too, and described Callier Effect to show that the choice of enlarger type (condensor vs diffusion) is relevant only to b&w printing.
The point is that the dyes of a colour film are, apart from their colour filtering effect, transparent. They do not induce diffusion, nor is any diffusion that is already present increased by colour dyes. Colour film looks the same to the enlarging lens whether lit by condensor or diffuser. Repeat: Colour film looks the same to the enlarging lens whether lit by condensor or diffuser. The only difference would be the result of the efficiency or inefficiency of flare suppression below the negative stage. Some enlargers are poor in this regard. The worst I've seen was a Meopta Axomat with a Meochrom head, which wouldn't have been too bad except for the cheap shiny plastic bellows. I sometimes worry, too, about my Beseler Dichro 67, because while some of its negative carriers are blackened, others are just the bare, brushed aluminium, even on the underside. OTOH I never see a halo of flare around the easel like the Meopta displayed, it's jet black immediately outside the projected image, so the doped cloth bellows that Beseler uses must do a good job. I suspect that enlargers which use focusing tubes instead of bellows would also have poor flare control below the negative stage, unless they were velvet lined or ribbed. These situations of flare don't prove anything for you, because they shouldn't ever occur, and if they do should be easy to remedy. If your enlarger suffers from flare in the image forming area (i.e. from the negative to the paper) then that is your fault for tolerating it when it is simply remedied. The quality of the illumination ABOVE the negative stage is of consequence only when you're printing traditional b&w, because of Callier Effect that I described before. regards, Anthony Farr ----- Original Message ----- From: "Caveman" <[EMAIL PROTECTED]> > Anthony Farr wrote: > > > Colour films lack opaque silver grains, having only dye clouds, as Caveman > > points out. What is missed by Caveman is that the dyes are simply tiny > > colour filters and do not impinge upon the direction of light rays passing > > through. Thus the Callier Effect is not invoked. > > The Caveman was thinking colour (where as you observed this effect does > not modify in a noticeable way the tonal reproduction). I'll leave B&W > for later, it is an even more interesting example (for the reason that > you don't have a "density" for the grain, it's there or not, and guess > what, it scans so much worse than colour, there must be an > explanation... ;-). I was interested by the effect in the reproduction > of the grain image. With difuse light, the image of a dye cloud tends to > "diffuse" too in its vicinity, introducing some primitive form of > interpolation. > > Until we get to B&W, here's a link to entertain you, especially if you > have a Minolta scanner: > > http://www.scanhancer.com/ > > cheers, > caveman > >
