[Alt-photo] Re: Alt-photo-process-list Digest, Vol 807, Issue 1

Fri Feb 14 18:04:32 UTC 2014

Thanks so much to everyone who answered my question about chlorophyll
printing ---I should have remembered myself that chlorophyll sensitivity
would not respond well to UV. However, I wonder if lamps specifically for
plants, various kinds of grow bulbs might work? I am going to look into the
various types and the light spectrum generated and do some experimenting. I
am familiar with Binh Dahn's work and was excited that he had figured out a
way of fixing the images using resin. Thanks again for your very helpful
answers!
Anne

On Fri, Feb 14, 2014 at 11:46 AM, Francesco Fragomeni <fdfragomeni at gmail.com
> wrote:

> Hi Anne,
>
> I didn't see this question until now but Tomas touched on some important
> points. Chlorophyll-a is the most active of the light absorbing pigments in
> plants for the purpose of photosynthesis. Obviously plants photosynthesize
> using sunlight but what's important to note is that sunlight contains many
> spectrums of different types of light, each of which have their own
> particular importance to the photosynthesis process. Sunlight actually
> contains only about 4% UV radiation so realistically not much compared to
> around 52% infrared radiation and 44% visible light radiation.
> Chlorophyll-a absorbs light most readily within the 400-450nm and 650-700nm
> wavelengths, Chlorophyl-b absorbs 450-500nm and 600-650nm. Those ranges are
> are within the visible light spectrum and fairly far outside of the UV
> spectrum. UV-a is around 315-400nm, UV-b is around 280-315nm, UV-c is
> around 200-280nm, and Vacuum UV (which is blocked by air but can operate in
> a vacuum) is around 100-200nm. Not much of those UV wavelength ranges are
> absorbed readily by Chlorophyl for the process of photosynthesis.
>
> With that said, I'm sure something would happen but to what degree will be
> for you to try out! I haven't tried working with chlorophyl prints in a uv
> box so I can't tell you for sure one way or another what will happen but I
> suspect some result will occur but probably not what you would expect when
> using direct sunlight.
>
> Best,
> Francesco
> www.francescofragomeni.com
>
>
> On Fri, Feb 14, 2014 at 10:56 AM, Tomas Sobota <tom at sobota.net> wrote:
>
> > Anne, I expected that someone more knowledgeable than me would answer
> your
> > question, but since nobody comes forward ...
> >
> > If by "chlorophyll prints" you mean something like the juxtaposing of a
> > negative on a living plant leaf to get after a time a positive image, my
> > answer to this would be an unambiguous "who knows", never having
> attempted
> > this technique.
> >
> > Looking at absorption spectra of chlorophyll a and chlorophyll b, for
> > example here: http://www.biologie.uni-hamburg.de/b-online/e24/3.htm
> > it is apparent that chlorophyll as a whole is mainly sensitive to the red
> > and blue regions of the spectrum, with a strong cut-off towards the near
> > UV. This, at least in theory, would preclude the use of UV light sources.
> >
> > Again, producing an image this way using strong sunlight needs many hours
> > or even several days of exposure, do you really mean to have your UV bank
> > on for such a long time?
> >
> > But if I were you I would try, who knows ...
> >
> > Tom
> >
> >
> >
> >
> > On Thu, Feb 13, 2014 at 7:16 PM, Anne Chansonette <chansonette at gmail.com
> > >wrote:
> >
> > > Does anyone know if it is possible to do chlorophyll prints using a UV
> > box
> > > instead of natural light? I am currently in the grey and unending New
> > > England winterland and don't want to wait months before working on a
> > > project!
> > > Anne at lesleyU
> > >
> > > Sent from my iPad
> > >
> > > > On Feb 21, 2013, at 7:00 AM,
> > > alt-photo-process-list-request at lists.altphotolist.org wrote:
> > > >
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> > > >
> > > > Today's Topics:
> > > >
> > > >   1. Re: Gelatin (Michel Debar)
> > > >
> > > >
> > > >
> ----------------------------------------------------------------------
> > > >
> > > > Message: 1
> > > > Date: Wed, 20 Feb 2013 23:55:36 +0100
> > > > From: Michel Debar <michel at debar.org>
> > > > To: The alternative photographic processes mailing list
> > > >    <alt-photo-process-list at lists.altphotolist.org>
> > > > Subject: [alt-photo] Re: Gelatin
> > > > Message-ID:
> > > >    <CAOtyDPLifUi342p44Anj5k2orcXT=fZkg=
> JtZfT3y_FqMRzLWw at mail.gmail.com
> > >
> > > > Content-Type: text/plain; charset=UTF-8
> > > >
> > > > An amazing quote from Douglas Cockerel 1910 book, Bookbinding and the
> > > care
> > > > of books :
> > > >
> > > > [...]
> > > > The following is quoted from ?Chambers? Encyclop?dia? on Gelatine:?
> > > >
> > > > ?Gelatine should never be judged by the eye alone.
> > > >
> > > > ?Its purity may be very easily tested thus: Soak it in cold water,
> then
> > > > pour upon it a small quantity of boiling water. If pure, it will
> form a
> > > > thickish, clear straw-coloured solution, free from smell; but if made
> > of
> > > > impure materials, it will give off a very offensive odour, and have a
> > > > yellow, gluey consistency.?
> > > >
> > > > [...]
> > > >
> > > >
> > > > ------------------------------
> > > >
> > > > _______________________________________________
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> > > >
> > > > End of Alt-photo-process-list Digest, Vol 807, Issue 1
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