Fluorescent technology is the same, whether in straight tubes or twisted ones. The phosphors react to an electrical stimulus and fluoresce, giving off light. The specific phosphors depend upon the formulation chosen by the manufacturer. A greater number of phosphors can create a more natural, accurate daylight light, but are more expensive. Thus, bulbs are created to meet specific needs. All fluorescent bulbs give off UV. It is a natural consequence of including blue/violet light in the color spectrum of the light. To eliminate it from the natural spectrum of the bulb results in a very red light. This is why very little UV is present in incandescent light, which is very red in color. To determine the amount of UV in different bulbs, request the spectral curves for each specific bulb from the manufacturers. Some will list the total UV, but on others, you will have to compare the curves and deduce the amount.
Filtration is the only effective method of removing the UV. This can be a coating put on the bulb by the manufacturer, or with sleeves. Sleeves are not an option for twisted bulbs such as compact fluorescents.
If your question is "do compact fluorescents represent a greater danger to collections than do regular (straight) fluorescents," the general answer is probably not, depending upon the specific bulbs in question (assuming equal wattage bulbs). However, if the regular bulbs are filtered and the compact fluorescents are not, the regular will be safer. So far as I know, both types have mercury, or an equivalent, which is required for them to fluoresce.
Marc
---- Martha Battle Jackson <[log in to unmask]> wrote:
> Has anyone heard of compact fluorescent lamp (CFL) bulbs being harmful to
> artifacts? Evidently they have mercury, so several of our site managers
> have questioned whether they should be replacing their regular office
> fluorescent lighting with CFL lamps.
>
>
>
> Thanks for your help!
>
>
>
> Martha Battle Jackson, Curator of Technology
> North Carolina Division of State Historic Sites and Properties
> Mailing Address: 4620 Mail Service Center, Raleigh, NC 27699-4620
> Street Address: 430 North Salisbury Street, Suite 1115, Raleigh, NC 27604
> 919/733-3877; ext. 236; FAX: 919/733-9515
> [log in to unmask]
>
>
>
> E-mail correspondence to and from this sender may be subject to the
> North Carolina Public Records Law and may be disclosed to third parties.
> The views expressed by the sender may not reflect those of my agency.
>
>
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