There are red led Christmas lights that are very reasonable to
purchase.  About $6.00 for a string of 35.  

Personally I like the Thomas safelight with the low pressure sodium
bulb.

I use 13 red LEDs (mounted close together) as a safelight.
Did all the standard tests with VC paper and no fogging.
Make sure they are red and not red/orange.

Jorge

Why  don't you just test it?  Put a coin on some paper, shine the bicycle
light at it for 5 minutes and see if the coin image shows when the paper is
developed.  This is not really a question that anyone can answer on a
newsgroup.  It is also faster to just test it.

PSsquare

Luigi de Guzman <luigi12081@cox.net> wrote in message news:

They are likely to work, but LEDs are nowhere near monochromatic.

The safelight test using coins should be done on paper that is already
uniformly exposed to give a mid to light grey.  What you are looking
for is the absence of a slightly paler grey where the coins were. If
you don't, your test will not be sensitive enough to ensure safety.
Kodak have a pdf file on safelight testing.

Can I use a darkroom safe light as my bicycle led?

Never mind, I'll ask in the alt.mountain-bike NG.

Luigi de Guzman <luigi12081@cox.net> wrote in message

solutions,

LEDs definitely make useful safelights, and you don't need to shell
out the big bucks for commercial LED safelights.

But you need to know something about LEDs and their effect on photo
paper, and you will need to do a little work. And most important, you
will need to do a safelight test just as you would for any safelight.

LEDs use various elements in their composition to get different
colors,  Unlike Laser Diodes, which put out light at just one
wavelength, LEDs put out a band of wavelengths centered at a
particular value.  For example, a RED LED may put out light with the
engergy centered at 630 nm and 99% of the energy between 615 and 645
nm.  The problem is that this information is available for individual
LEDs, but isn't usually provided by the people who assemble them into
lamps or products.

In general, photo paper is pretty insensitive to light with a
wavelength longer than about 600 nano meters.  That wavelength looks
yellow-orange to the human eye.  This says that a yellow LED will fog
paper pretty easily (believe me, it does), an orange (amber) LED may
fog it it the light is very bright, and a red LED can be pretty bright
without fogging film.  Filters can be used to help eliminate light
with shorter wavelengths from the spectrum -- making the orange LEDs a
little safer.  A Rosco #24 Scarlet or #25 Red filter gel works great.

It might sound like a RED LED is the way to go.  Well... hold on. The
other factor to consider is that the human eye is pretty insensitive
to red.  It sees amber much better.  IMHO the best color to use is
orange.  If it is used with a red-orange filter, it can be pretty
bright and not fog film.

Where to get them...  Among the most widely available and cheapest
bright LED packages are truck tail lights.  Check out the bus or truck
in front of you next time you are out driving.  These run on 12 volts
and can be very bright.  To power them, a cheap 12 volt power supply
from Radio Shack should do the job.  A rule of thumb is that you need
1 amp of capacity for every 25 LEDs.

Here's another trick.  I have a good general safelight, but some areas
of the darkroom remain, well, dark.  So I use little lamps with a
single LED to light specific things.  For example, I have a single LED
that shines on the thermometer at the developing tray.  I have another
that illuminates the f stop scale on the enlarging lens.  Yet another
shines on the knobs on the radio.  Shine is probably an
over-statement.  These run on almost no power and I have them set so
they give me just enough light.  That minimizes the possibility of
safelight fog.

Here are some useful web links...
Vendors of LED tail lights...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=50466&item=246
2175543

http://www.superbrightleds.com/truck_lights.htm

Web site with lots of LED info...  http://www.ledmuseum.org/

Major makers of LEDs include Lumileds, Kingsbright, and Luxeon