Homebrew PCBs

My 60 watt incandescent yellow bug light finally burned out after years of use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement but none found. Walmart had a 90 watt one but I think that would be too bright for my dry film darkroom use.

Has anyone had any experience with the yellow fluorescent bulbs used as a dark room bulb? I'm concerned that since it is a fluorescent source it may still emit UV. Or does the yellow glass effectively block the UV?

LED light source
 



________________________________

 From: Ray <rcbuckiii@...>
To: Homebrew_PCBs@yahoogroups.com 
Sent: Monday, July 22, 2013 2:27 PM
Subject: [Homebrew_PCBs] Yellow CFL bulb
 


  
My 60 watt incandescent yellow bug light finally burned out after years of use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement but none found. Walmart had a 90 watt one but I think that would be too bright for my dry film darkroom use.

Has anyone had any experience with the yellow fluorescent bulbs used as a dark room bulb? I'm concerned that since it is a fluorescent source it may still emit UV. Or does the yellow glass effectively block the UV?


 

[Non-text portions of this message have been removed]

Some random thoughts ....

How about an appropriately colored gel filter from a camera store or photographic supplier?  Kodak used to make and sell this, but ....

Maybe the supplier of the photosensitive media can suggest a vendor for a bulb or a filter.

In a pinch, you may be able to get some candy-apple model spray paint at a well-stocked hobby store, and either spray a lampshade or the bulb itself.

73
Jim N6OTQ



>________________________________
> From: Ray <rcbuckiii@...>
>To: Homebrew_PCBs@yahoogroups.com 
>Sent: Monday, July 22, 2013 4:27 PM
>Subject: [Homebrew_PCBs] Yellow CFL bulb
> 
>
>My 60 watt incandescent yellow bug light finally burned out after years of use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement but none found. Walmart had a 90 watt one but I think that would be too bright for my dry film darkroom use.
>
>Has anyone had any experience with the yellow fluorescent bulbs used as a dark room bulb? I'm concerned that since it is a fluorescent source it may still emit UV. Or does the yellow glass effectively block the UV?
>

[Non-text portions of this message have been removed]

On Mon, 22 Jul 2013 21:27:19 -0000, you wrote:

>My 60 watt incandescent yellow bug light finally burned out after years of use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement but none found. Walmart had a 90 watt one but I think that would be too bright for my dry film darkroom use.
>
>Has anyone had any experience with the yellow fluorescent bulbs used as a dark room bulb? I'm concerned that since it is a fluorescent source it may still emit UV. Or does the yellow glass effectively block the UV?
>
>
>
>------------------------------------
>
IIRC yellow tubes were once used in offset print darkrooms.
Might be interesting to check with printing supply houses.

Years ago we used 15 watt standard start red tubes
in the photographic darkroom for printing, even with
polycontrast paper. Safer than the high dollar Kodak
gel filters and 2x-3x brighter. We had to wrap a strip 
of black tape on each end because the phosphor wasn't 
real good at the ends. Rapid start tubes did not work at all, 
may as well use white.

Keith Bowers WB4LSJ- Thomasville, NC

Probably not yellow glass but yellow phosphor coating. All fluorescent 
lamps work by using UV from a mercury vapor light source to excite a 
phosphor coating on the inside of the tube. Any missing phosphor will 
allow some UV to escape although most glass does block some UV rays.
For what it's worth, Amazon has some 60 w bug lamps.

On 7/22/2013 6:35:23 PM, kabowers@... wrote:
 > On Mon, 22 Jul 2013 21:27:19 -0000, you wrote:
 >
 > >My 60 watt incandescent yellow bug light finally burned out after years
 > of use. I checked several stores (Walmart, Home Depot, Lowes) for a
 > replacement but none found. Walmart had a 90 watt one but I think that
 > would be too bright for my dry film darkroom use.
 > >
 > >Has anyone had any experience with the yellow fluorescent bulbs used 
as a
 > dark room bulb?
 > I'm concerned that since it is a fluorescent source it may still emit 
UV. Or does the yellow glass effectively block the UV?

 > >
 > >
 > >
 > >------------------------------------
 > >
 > IIRC yellow tubes were once used in offset print darkrooms.
 > Might be interesting to check with printing supply houses.
 >
 > Years ago we used 15 watt standard start red tubes
 > in the photographic darkroom for printing, even with
 > polycontrast paper. Safer than the high dollar Kodak
 > gel filters and 2x-3x brighter. We had to wrap a strip
 > of black tape on each end because the phosphor wasn't
 >
 > real good at the ends. Rapid start tubes did not work at all,
 > may as well use white.
 >
 > Keith Bowers WB4LSJ- Thomasville, NC
 >
 >
 >
 > ------------------------------------
 >

I just remembered seeing colored CFLs at Home Depot.  I think yellow was in their batch.

Not cheap, though.

73
Jim N6OTQ



>________________________________
> From: Jim Hancock <jhancock1@...>
>To: homebrew_pcbs@yahoogroups.com 
>Sent: Monday, July 22, 2013 7:06 PM
>Subject: Re: [Homebrew_PCBs] Yellow CFL bulb
> 
>
>Probably not yellow glass but yellow phosphor coating. All fluorescent 
>lamps work by using UV from a mercury vapor light source to excite a 
>phosphor coating on the inside of the tube. Any missing phosphor will 
>allow some UV to escape although most glass does block some UV rays.
>For what it's worth, Amazon has some 60 w bug lamps.
>

[Non-text portions of this message have been removed]

> Ray wrote:
> I'm concerned that since it is a fluorescent
> source it may still emit UV. Or does the
> yellow glass effectively block the UV?

Or use a large LED setup.

Non white LEDs have no UV out.

resend - evidently didn't get through

LED lightsource is monochromatic so the ends of tubes leaking light is a moot point. To me it is the obvious choice.
Kirk

--- In Homebrew_PCBs@yahoogroups.com, "Ray" <rcbuckiii@...> wrote:

>
> My 60 watt incandescent yellow bug light finally burned out after years of use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement but none found. Walmart had a 90 watt one but I think that would be too bright for my dry film darkroom use.
> 
> Has anyone had any experience with the yellow fluorescent bulbs used as a dark room bulb? I'm concerned that since it is a fluorescent source it may still emit UV. Or does the yellow glass effectively block the UV?
>

I use one of these:
http://www.rei.com/product/709063/petzl-tactikka-plus-led-headlamp

Works great


On Mon, Jul 22, 2013 at 8:12 PM, Jim <n6otq@yahoo.com> wrote:

> **
>
>
> I just remembered seeing colored CFLs at Home Depot.  I think yellow was
> in their batch.
>
> Not cheap, though.
>
> 73
> Jim N6OTQ
>
> >________________________________
> > From: Jim Hancock <jhancock1@...>
> >To: homebrew_pcbs@yahoogroups.com
> >Sent: Monday, July 22, 2013 7:06 PM
> >Subject: Re: [Homebrew_PCBs] Yellow CFL bulb
>
> >
> >
> >Probably not yellow glass but yellow phosphor coating. All fluorescent
> >lamps work by using UV from a mercury vapor light source to excite a
> >phosphor coating on the inside of the tube. Any missing phosphor will
> >allow some UV to escape although most glass does block some UV rays.
> >For what it's worth, Amazon has some 60 w bug lamps.
> >
>
> [Non-text portions of this message have been removed]
>
>  
>


[Non-text portions of this message have been removed]

Thats odd... I just went to my walmart a while ago and got 40w cfl bug
lights, and they had a few brands of incandescent bulbs, what state are you
in that they no longer carry incandescent bug bulbs?
On Jul 22, 2013 7:26 PM, "Shannon Haworth" <shannon.haworth@...>
wrote:

> I use one of these:
> http://www.rei.com/product/709063/petzl-tactikka-plus-led-headlamp
>
> Works great
>
>
> On Mon, Jul 22, 2013 at 8:12 PM, Jim <n6otq@...> wrote:
>
> > **
> >
> >
> > I just remembered seeing colored CFLs at Home Depot.  I think yellow was
> > in their batch.
> >
> > Not cheap, though.
> >
> > 73
> > Jim N6OTQ
> >
> > >________________________________
> > > From: Jim Hancock <jhancock1@...>
> > >To: homebrew_pcbs@yahoogroups.com
> > >Sent: Monday, July 22, 2013 7:06 PM
> > >Subject: Re: [Homebrew_PCBs] Yellow CFL bulb
> >
> > >
> > >
> > >Probably not yellow glass but yellow phosphor coating. All fluorescent
> > >lamps work by using UV from a mercury vapor light source to excite a
> > >phosphor coating on the inside of the tube. Any missing phosphor will
> > >allow some UV to escape although most glass does block some UV rays.
> > >For what it's worth, Amazon has some 60 w bug lamps.
> > >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>


[Non-text portions of this message have been removed]

The phosphor coating is usually distributed unevenly near the ends of
the tube where the metal caps are allowing the UV out and direct
viewing of the electrodes.  Tubes specifically designed for UV output
like germicidal and EPROM eraser lamps use a glass which is more
transparent to UV.  Quartz is needed for the 254nm mercury line and
synthetic quartz is needed for the 184nm mercury line.

There are a number of different phosphors which emit yellow near the
589nm sodium line which is safe for industrial photoresists.  The
lower frequency safelight cutoff frequencies are 625nm (deep
ortho-red), 610nm (ortho-red), 580nm (amber), and 555nm
(amber-yellow).  I think we used amber for black and white enlarging
paper in a darkroom.

On Mon, 22 Jul 2013 20:06:46 -0400, Jim Hancock <jhancock1@...>
wrote:

>Probably not yellow glass but yellow phosphor coating. All fluorescent 
>lamps work by using UV from a mercury vapor light source to excite a 
>phosphor coating on the inside of the tube. Any missing phosphor will 
>allow some UV to escape although most glass does block some UV rays.
>For what it's worth, Amazon has some 60 w bug lamps.

Thanks for the comments.

I decided to go ahead and run a test. The worst that could happen is I would have to strip the board and re-apply the dry film.

I went to Home Depot and purchased a Orange 13 watt CFL bulb. The package calls it a Ecobulb Party Bulb. I purchased the Orange bulb instead of the yellow one because I felt it would block more UV and white light. When I turned it on in the dark room it appeared to be about the same amount of yellow light as my original 60 watt incandescent bulb. I took a blue object into the dark room and it appeared to be black which indicated no UV was present.

With the bulb turned on I placed a negative on the top side of a double sided board. I use .022 wires as guides to locate the negative into the correct position. I need a fair amount of light so as to see the holes in the board and negative. I exposed the top side and then turned the board over and placed the bottom negative into position. I then exposed the bottom side.

When I developed the board it came out perfect. So this confirmed that the Orange CFL is totally suitable as a light environment to work in. My bulb is about 3 feet above and 2 feet off to the side of my work area. The blue dry film appears black when the bulb is on which again indicates no UV is being emitted from the bulb.

I hope this information is helpful to someone.

Ray

--- In Homebrew_PCBs@yahoogroups.com, David <davidwhess@...> wrote:

>
> The phosphor coating is usually distributed unevenly near the ends of
> the tube where the metal caps are allowing the UV out and direct
> viewing of the electrodes.  Tubes specifically designed for UV output
> like germicidal and EPROM eraser lamps use a glass which is more
> transparent to UV.  Quartz is needed for the 254nm mercury line and
> synthetic quartz is needed for the 184nm mercury line.
> 
> There are a number of different phosphors which emit yellow near the
> 589nm sodium line which is safe for industrial photoresists.  The
> lower frequency safelight cutoff frequencies are 625nm (deep
> ortho-red), 610nm (ortho-red), 580nm (amber), and 555nm
> (amber-yellow).  I think we used amber for black and white enlarging
> paper in a darkroom.
> 
> On Mon, 22 Jul 2013 20:06:46 -0400, Jim Hancock <jhancock1@...>
> wrote:
> 
> >Probably not yellow glass but yellow phosphor coating. All fluorescent 
> >lamps work by using UV from a mercury vapor light source to excite a 
> >phosphor coating on the inside of the tube. Any missing phosphor will 
> >allow some UV to escape although most glass does block some UV rays.
> >For what it's worth, Amazon has some 60 w bug lamps.
>

HI,

 

Fluorescent tubes can be used safely in the dark room. These are special
types which are designed not to have any UV radiation. There are different
types of yellow fluorescent tubes. It depends if the tube is a typical
yellow color tube with some UV leakage or a special tube with just yellow
alight and UV removed.

A way around this are UV sleeves to stop fluorescent tubes causing color
fading. UV light has been known to cause color fading and special sleeves UV
preventing sleeves are available to remove UV radiation, and could be used
to convert normal yellow fluorescent tubes to be safe in the dark room.  

Hope this helps?

Cheers

Tim Gibbs

 

My 60 watt incandescent yellow bug light finally burned out after years of
use. I checked several stores (Walmart, Home Depot, Lowes) for a replacement
but none found. Walmart had a 90 watt one but I think that would be too
bright for my dry film darkroom use.

Has anyone had any experience with the yellow fluorescent bulbs used as a
dark room bulb? I'm concerned that since it is a fluorescent source it may
still emit UV. Or does the yellow glass effectively block the UV?

 



[Non-text portions of this message have been removed]