>
>There is clearly a lot about enlargers I don't understand. Wouldn't
>anything on the plane of the negative, (i.e. dirt, image) be EXPECTED to
>be in sharp focus on the print? I'm trying to understand how you could
>have the IMAGE from the neg in sharp focus, but not scratches, dust
>etc. How does that work?
ok... talkin' to a guy here who prints his negs on very rough water color
paper. still,
how the light is collated alters the appearance (or not) of scratches, and
the size of the dust. i'm not, i'm sorry, an expert on enlargers, so i bow
to those who know more.
however, i do know that apparent sharpness can be brought about by
developing technique too. beutler's formula (did i spell that right) or pyro
gallic acid will alter the boundaries of light and dark on a negative, and
produce an apparent sharpness by taking the bromies from the lighter
side of the image (darker on negative) and piling them up near the boundary,
while moving some of the bromies from the darker side of the image (lighter
on the neg) away from the boundary. when creating the sharpness algorithm
for scanners (i worked for hp in the scanner group, wrote the programmer's
toolkit for the hp scanners - a past life) we used a similar technique, just
moved the bits around instead of bromide molecules.
remember too that the negative has a plane within which it is in/out of focus.
depending where the image/dust lies, it may be above the negative and thus
thrown slightly out of focus. again, enlarger optics isn't my bag. just
throwing
some thoughts out.
i've gone back, just now, and read the beginning of this thread... just as an
fyi, i've used my 150 schneider lens for 4x5 enlargement since i started making
4x5 enlargements. it's real life is as a normal lens, just never used it
for that.
heck, still has the shutter within it. but i'm a practicing contrarian
;-) i buy puts
when people buy calls, i was a hippy when people had crew cuts (i say
this to ensure
you know my bias about doing things). even the new beer we are about to
release
breaks all the rules of microbreweries! just my way of doing things.
i've thought about making an 8x10 enlarger. i'd either use an old 8x10
i've got lying
around, or possibly build one. either way i'd build mine horizontal
(gravity and a large
negs don't mix well). i'd build a light box behind the neg holder. i'd
make the light
box interchangeable so i could play with different light sources. when i
did print silver
i swore by the cold light. just made things real easy for me. making the
unit rigid and
all critical parts parallel (Ron Baker's note of 5/14) is critical to
sharpness. the two tough
parts for the enlarger are (imho), the raising and lowering of the unit,
and the film holder.
before i build an enlarger i need to complete two 7 foot high
full-range-horn speakers. i
figure that before i get married again i'd get the speakers built, moved
into the living
room; kinda make them a permanent feature. those of you who have had
spousal-audio
disagreements know from where i come. i'm sure there is a flaw in this
logic, i'd probably
be safer building an 8x10 enlarger and hiding it in the basement. i did
say i'm a bit of a
contrarian, no?
peter
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