In article <3v9fs1$m1u@rover.ucs.ualberta.ca>, mruth@rr.ualberta.ca
says... (some deletions)

>I don't know if I should buy a diffusion enlarger or a condensor
>enlarger.
>I've read in various books that diffusion enlargers
>don't show scratches or dust as readily as condensor enlargers, and they
>don't scatter light as easily in dense parts of the negative. Many
>outstanding photographers such as Ansel Adams used to recommend them.
>My question: Is the diffusion enlarger the way to go?

In a word, maybe. I have had much experience in the fields of audio
and photography, and while photography is weighed down by a plethora
of myths, fortunately it cannot hold a candle to the level of hooeyness
that exists in the audio world. One of the myths that does persist in
photography holds that diffusion enlarging is inherently superior to
condenser enlarging (some of the reasons given are cited above).
- If you place the same negative in the same enlarger, using the same
enlarging lens and paper, and change the head from a condenser to
a diffusion type, and make prints matched in average density and size,
the print made using the diffusion head will appear to have smoother
grain, slightly less prominent scratches, and a somewhat longer range
of tones. (in other words,the print is lower in contrast by about
a grade)
- If the above conditions are again met, but you adjust the paper
contrast in the prints made from the two different light sources so
that it matches, the prints will look remarkably similar (the two
light source types are about a paper grade different).
- If the conditions in the first instance are met, but the development
of the film is adjusted, you will be able to make prints with
the two different light sources that are virtually identical, though
there would be a slight advantage with the diffusion source regarding
dust and scratches.

Additional information:
- All light sources are uneven, but condenser sources tend to be
smoothly brighter near the center and can be compensated by an
edge-corner burn-in. Diffusion sources tend to be irregularly
uneven, and are difficult to compensate for in printing.
- The tungsten light in a condenser system turns on rapidly, which
makes timing easier - diffusion sources often need to warm-up, and
are more likely to change intensity with time.
- Variable contrast filters are somewhat easier to use with tungsten
sources than with the color of many diffusion sources.
- Some diffusion systems are physically shorter, making the making
of large prints in a darkroom with a low ceiling easier.
- I have undoubtedly forgotten many things, and have probably
originated a few myths with this post, but I hope this helps.