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

Fri Feb 14 16:47:59 UTC 2014

Jack touches on another great resource. Bihn Dahn is very gracious and I'd
recommend maybe sending him an email if you have other questions about
this. I think he's operating out of Tempe, AZ at ASU now.

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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