From: Geoffrey S. Mendelson on
Ken Hart wrote:
> The wall switches that are used for three-way light circuits (such as the
> light in a stairway where there is a switch downstairs and another upstairs
> to control one light) are single-pole-double-throw switches. They have three
> connections: have the power coming in on the 'common', and out on one of the
> two others depending on the position of the switch. One position of the
> switch supplies power to the safelight, the other position supplies power to
> the enlarger.

Thanks, I have never seen them here. I'll have to ask. Instead of using
3 way light switches, hallways have push button start timers. They are
scientificly designed through years of measurement and careful observation
to turn off the light just before you get your door open and therefore
plunge you into darkness. :-)

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/
From: Claudio Bonavolta on
On 21 août, 21:12, Andrew Price <ajpr...(a)free.fr> wrote:
> On Tue, 21 Aug 2007 05:33:26 -0700, Claudio Bonavolta
>
> <clau...(a)bonavolta.ch> wrote:
>
> [---]
>
> >In your situation, I would try to find a local supplier of raw
> >chemicals and mix my own, it may be easier.
>
> Good suggestion. See also Lloyd Erlick's article :
>
> <http://www.heylloyd.com/technicl/bulkchem.htm>
>
> on this subject. The other articles on his site are also well worth
> reading.


Some more comments as Geoff seems to need a post-nuclear war survival
guide ...

One more option for the safelights: to make my computers screens
inactinic when working in my darkroom I cover the screens with red
plastic film called Rubylith. This is not just a red film as it is
intended for masking use in graphic arts and printers. It is very
efficient and cheap, the only drawback is that it is becoming rare as
most of graphic work has gone digital.
There is also an amber version called Amberlith.

Regarding self-made chemistry, a few other pointers:
- Steve Anchell's pair of books (meant to be practical cookbooks and
not scientific litterature), check with Amazon.
- I put a copy of Kodak's J-1 publication which contains all basic
formulas (and more) here (20MB pdf file):
http://www.bonavolta.ch/hobby/files/Kodak%20j-1.pdf
- Photo Formulary have also published a bunch of formulas (under
Technical Infos):
http://www.photoformulary.com
- The same with Digital Truth together with a database of development
times: http://www.digitaltruth.com
- Ryuji Suzuki's website (seems down, hopefully temporarily):
http://www.silvergrain.org
- http://www.jackspcs.com
- and many other websites ...

If Geoff stays with classic formulas like D-76 and D-72 (Dektol's
public formula), the basic ingredients are similar and the number of
raw chemicals could remain limited.
If he prefers more environmentally-friendly formulas then those based
on ascorbic acid (Vitamin C) are available (Mytol, E-72, Ryuji's
formulas, etc ...).

Regarding the raw chemicals in Israel, I did a quick search and found
following website that may be a good start: http://dir.chemnet.com/Regional/Israel/
One of the links points to an university, that could be a good idea to
ask the chemistry department of a university what suppliers they use.

So, good luck !
Claudio Bonavolta
http://www.bonavolta.ch

From: Geoffrey S. Mendelson on
Claudio Bonavolta wrote:
> Some more comments as Geoff seems to need a post-nuclear war survival
> guide ...

I don't think so. It may seem that way, but it's a more of a combination
of the effects of digital photography and the movement of research
to the China and India, combined with post 9/11 paranoia.

I can already see the effects here, some common household chemicals
such as ammonia are banned. I also see that in the U.S. people who
buy scales and organic solvents are suspected of running meth labs,
or a bomb factory.

When I was a child growing up in Philly, I had a microscope and a
small home chemical lab. By 1970 the organic solvents I used
e.g. xylene and acetone, were banned and all sorts of chemicals
were no longer sold. At one time you could buy them in a rack in
a hobby shop, like spices at a supermarket, but they were gone.

> One more option for the safelights: to make my computers screens
> inactinic when working in my darkroom I cover the screens with red
> plastic film called Rubylith. This is not just a red film as it is
> intended for masking use in graphic arts and printers. It is very
> efficient and cheap, the only drawback is that it is becoming rare as
> most of graphic work has gone digital.
> There is also an amber version called Amberlith.

I'll have to look for it. It should be easy to find if there are
any graphic arts companies left. My guess is that they have all gone
digital, it's obvious if you open any newspaper that everything is
done with photoshop.


> Regarding self-made chemistry, a few other pointers:
> - Steve Anchell's pair of books (meant to be practical cookbooks and
> not scientific litterature), check with Amazon.
> - I put a copy of Kodak's J-1 publication which contains all basic
> formulas (and more) here (20MB pdf file):
> http://www.bonavolta.ch/hobby/files/Kodak%20j-1.pdf

Downloading it now, thanks.


> Regarding the raw chemicals in Israel, I did a quick search and found
> following website that may be a good start: http://dir.chemnet.com/Regional/Israel/
> One of the links points to an university, that could be a good idea to
> ask the chemistry department of a university what suppliers they use.

The university is Hebrew University, where I got my start
in Israel in their computer science department. I'll ask them if
they can help.

Thanks for all your help,

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/
From: Claudio Bonavolta on
On 22 août, 12:39, g...(a)mendelson.com (Geoffrey S. Mendelson) wrote:
> Claudio Bonavolta wrote:
> > Some more comments as Geoff seems to need a post-nuclear war survival
> > guide ...
>
> I don't think so. It may seem that way, but it's a more of a combination
> of the effects of digital photography and the movement of research
> to the China and India, combined with post 9/11 paranoia.
>
> I can already see the effects here, some common household chemicals
> such as ammonia are banned. I also see that in the U.S. people who
> buy scales and organic solvents are suspected of running meth labs,
> or a bomb factory.
>
> When I was a child growing up in Philly, I had a microscope and a
> small home chemical lab. By 1970 the organic solvents I used
> e.g. xylene and acetone, were banned and all sorts of chemicals
> were no longer sold. At one time you could buy them in a rack in
> a hobby shop, like spices at a supermarket, but they were gone.

Don't worry this was just a joke ...
Fortunately here in Europe (except UK maybe) we feel much less the
9/11 effects.
By the way, chemicals were already less widely available before due to
safety regulations and another problem is that many chemical companies
ask you to buy quantities way to large for the simple hobbyist.

> > One more option for the safelights: to make my computers screens
> > inactinic when working in my darkroom I cover the screens with red
> > plastic film called Rubylith. This is not just a red film as it is
> > intended for masking use in graphic arts and printers. It is very
> > efficient and cheap, the only drawback is that it is becoming rare as
> > most of graphic work has gone digital.
> > There is also an amber version called Amberlith.
>
> I'll have to look for it. It should be easy to find if there are
> any graphic arts companies left. My guess is that they have all gone
> digital, it's obvious if you open any newspaper that everything is
> done with photoshop.

A link to the manufacturer: http://www.ulano.com
They have a link to company Arta Graphics being their distributor for
Mid-East region:
http://www.arta-israel.co.il/sg_product~7010~13~54.htm
But I can't read Hebrew ...

Good luck,
Claudio Bonavolta
http://www.bonavolta.ch



From: Nicholas O. Lindan on
"Claudio Bonavolta" <claudio(a)bonavolta.ch> wrote

> Rubylith. This is not just a red film as it is
> intended for masking use in graphic arts and
> printers. It is very efficient and cheap, the
> only drawback is that it is becoming rare as
> most of graphic work has gone digital.

Pre-press equipment and supplies can often be found
at outfits that supply the silk-screening industry.

A good art-supplies store will often carry rubylith
for poster silk-screening.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/index.htm
n o lindan at ix dot netcom dot com


First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4 5 6 7
Prev: Use Kodak Tray Siphon to Wash film?
Next: sharpness & grain