[filmscanners] Re: Difficult scan problem

["Arthur Entlich" <artistic-1@shaw.ca>]

I have been in private correspondence with Rob about this matter.

Like everyone else, I assumed when he referred to fluorescence lighting
he was referring to fluorescent lighting.  However, he has since
mentioned two things which make me think we are speaking of something else.

He spoke about making minerals showing oil fluoresce, and secondly he
mentioned to me that the neg images have a "base color" that is golden.

Having been a rock hobbyist many years ago, I used to work with
fluorescing minerals which "glow" under exposure to short wave UV light
sources.  I also know that oils fluoresce under UV light, and I know
that a golden colored negative is one that is exposed to very blue
lighting or subjects.

I suspect that what Rob is referring to is not what we typically refer
to as fluorescent lighting, which is indeed usually a discontinuous and
unbalanced lighting source, but a short wave UV light source.  I am
still awaiting Rob getting back to me about this for confirmation.

I have some articles about photographing under UV to capture
fluorescence and phosphorescence which I can refer to if this is what we
are speaking about.

Getting back to fluorescent lighting as a photographic lighting source
for a second, I do the majority of my still life work with fluorescent
lighting.  I have never liked working with electronic flash.  I really
enjoy having the constant well-diffused lighting source that allows me
to make all sort of subtle adjustments, using reflective bounce
lighting, and even coloring the light via gels and bouncing off colored
cards.  The results I get with this method eliminates almost all the
guess work.  BUT, it took me a long time to find the correct lighting
tubes and filtration to get full spectrum balanced daylight, and I can't
work much bigger than compositions more than about 2 foot by 3 foot.  I
have purchased dozens of different "full spectrum" bulbs over the years
and mixed them in fixtures to get the light balance I was after, and I
still have to use filters on the camera lens.  I knew I got it "right"
when I was able to shoot Kodachrome and get daylight results.  It took
about 30-40 rolls to get there.  I now use Fujichrome films, which are
more forgiving.  I still use gray cards and I still bracket every shot,
but I'm very pleased with the results I get now.

Art
TonySleep@halftone.co.uk wrote:

> On Mon, 15 Apr 2002 20:30:13 -0500  Laurie Solomon (laurie@advancenet.net)
> wrote:
>
>
>>Tony, what if the "constant colour temp lightsource" is a fluorescent
>>discontinuous light source such as what he has said was the light source
>>for
>>the microscope; will what you suggest still hold?
>>
>
> I have used col neg (Superia and other Fuji mostly) in various
> fluorescents and it copes wonderfully with no camera filtration. Unless the
> microscope lamp is very weird it should be possible to get good results.
>
> I haven't tried it of course, but I use the eyedroppers as described for
> colour correction with just about every colour neg I scan. Usually I use
> Vuescan White Balance as a starting point, save in 16bit, then do this in
> PS. PS Auto levels is frequently very wrong and I seldom use that.
>
> With crystals, mostly there is going to be a problem finding anything in
> the image which is a mid-ish-grey to use the midtone eyedropper on. But
> fixed exposure and illuminant remove the variables, so provided a decent
> set of corrections can be obtained and saved using an image which does
> contain a neutral grey, merely applying the saved levels adjustments should
> give a good result with all images from this setup. Close enough that all
> that may need doing would be limited to overall gamma, perhaps contrast,
> and maybe tweak the hue and saturation a little on some subjects.
>
> Oddly enough, over 30yrs ago I had a maths teacher whose hobby was
> photomicroscopy of crystals. He used (Agfa) colour neg and produced awesome
> 20x16's. It's worth persevering here I think.
>
> Regards
>
> Tony Sleep


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