Homebrew PCBs

On 29/01/2010 02:50, James wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, James Bishop<bishopaj@...>  wrote:
>    
>> It might also have something to do with the UV wavelength. I think
>> LEDs have a longer wavelength, close to purple, while the tubes might
>> be further into the UV range. This may affect exposure time or
>> resolution.
>>
>>
>>      
>
> Fluorescent tubes emit light in sharp peaks of fairly specific wavelenghts. There are several peaks produced by the mercury vapor discharge itself, and others produced by the phosphor coating which is excited by absorbing the short wave UV from the discharge. Ordinary glass absorbs shortwave UV, so special germicidal and ozone producing tubes are made of quartz.
>    

PCBs require long wave UV which isn't absorbed by ordinary glass.

Leon