Author Topic: Which Safelight?  (Read 1093 times)

Offline Steve Harpold

  • Full Member
  • ***
  • Posts: 111
Re: Which Safelight?
« Reply #15 on: July 21, 2019, 10:15:24 AM »
Hey all,

Quick update on safe lights, in most cases it is a thing of the past.

Why?
Old style light bulbs (not that old for some on here) incandescent or florescent have our light in a very broad spectrum. Not exact but from around 300-700 NM. Emulsion is sensitive to light from 280-420 NM maybe a little higher. The light NM range that emulsion is sensitive to is not visible hence would make a poor choice for lighting applications.

Hence?
LED tubes, lights used for visible light application would not emit light in the 300-420 as it would be a waste of energy (it is not visible) so it is not necessary to use a filter to filter out wave lengths between 300-420 since there isn’t anything there anyway or such a small amount it is irrelevant.

When buying new LED tubes?
Look at the spectrum of light and make sure 300-420 NM is not present and you will be good to go


Offline screenxpress

  • !!!
  • Gonzo Member
  • ******
  • Posts: 2183
Re: Which Safelight?
« Reply #16 on: July 21, 2019, 03:57:05 PM »
Don't need em anymore as we don't use Darkrooms.

Our screen room is a normal room with regular tube lights in the ceiling. We coat, store, image, burn and even washout screens in regular shop light conditions.

Thanks John.

I stopped using protective lighting years ago.  Obviously you can't leave dry screens out under the lights for storage, but coating, set-up for exposure, and washout under florescent bulbs has not been an issue.
Anything important is never left to the vote of the people. We only get to vote on some man; we never get to vote on what he is to do.  Will Rogers

Offline Admiral

  • Hero Member
  • *****
  • Posts: 685
Re: Which Safelight?
« Reply #17 on: July 22, 2019, 11:57:25 AM »
FYI our LED lights are GREAT at exposing emulsion.  They are 'non UV emitting' LED high bay lights but they sure do expose emulsion.  I tinted them with yellow film and the film itself degraded over less than a year from the UV the LEDs are in fact putting out.

I will be putting a stronger filter under them shortly in addition.  We don't get much UV scatter / exposure but enough to have to cover tops of screen racks. 

It is very bright in our dark room, we have 3 of these 500 watt bright LED lights in our dark room fyi.

Filters I got are from UVprocess.com, there are a few options there.  I also put the amber film on a large glass window between 2 rooms so we can see into the dark room too.

Offline Zelko-4-EVA

  • Hero Member
  • *****
  • Posts: 513
Re: Which Safelight?
« Reply #18 on: July 22, 2019, 01:48:22 PM »
we have the standard drop ceiling size 2x4 LED lights in our screenroom - i also used the UVprocess.com amber film.  i havent measured the UV output in our screen room but now its got me thinking...


Offline Admiral

  • Hero Member
  • *****
  • Posts: 685
Re: Which Safelight?
« Reply #19 on: July 22, 2019, 01:52:12 PM »
Correction - they are 100 watt VTac high bay UFO lights.  Still quite bright.  500 watt would be absurdly bright though.