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.
>