From: Sandy King (sanking@clemson.edu)
Date: 07/19/03-11:25:33 AM Z
Hi Phillip,
About the clean room, yes, that would help. I normally keep a
DuraCraft air cleaner with a Hepa filter that is rated to remove
about 99.99% of air-borne particles in both the exposure room and in
the room where I dry coated tissue. However, due to recent travels
the filters were turned off for a few weeks and I became really aware
of the seriousness of the problem in looking at the glass frame of
the easel with the exposing lights turned on. And of course, there is
a fan in the exposing unit so when the light go on the fan does also,
and you can see all the trash being blown around.
Regarding the danger of the UV radiation, the BLB tubes with the
funny purple/blue color do not really put out any more UV radiation
than the more commonly used BL tubes that appear much whiter to the
eye. In fact, the only difference between the two is that there is
cut-off filter in the BLB tubes that eliminates virtually all light
above about 420 nanometers.
Sandy
>Hello Sandy,
>
>Neutralizing both positive and negatively charged motes and keeping
>them from lighting on a large
>horizontal surface is nearly impossible outside of a "clean room".
>One thing is that the glass itself creates quite
>an e-field once you rub it with a cloth when cleaning. To illustrate
>how much so: I have a light table at my day
>job that is built within a table having two 3-foot fluorescent
>tubes. One of the tubes never lights when you turn
>the switch 'on'. Simply rubbing the glass with a sheet of paper a
>couple of strokes will fire the lamp!
>
>I've noticed commercial static air cleaners for sale by retailers
>like Sharper Image and others:
><http://www.ionicbreezeairpurifier.com/>http://www.ionicbreezeairpurifier.com/
>These units might help with the volume of motes in a given room
>depending on the size of the room.
>Traffic through the area, drafts, ceiling type, flooring, clothing,
>etc. all contribute their share of "dust".
>
>Although a "clean room" is best, I have managed in the past by
>taking a different tack by not trying to
>eliminate them at all. The trick is to keep them moving. As long
>as the glass is not acting like a magnet,
>which is an easy fix with an antistatic liquid. A good fan blowing
>across the surface during exposure
>keeps the appearance of dust on the final image to a minimum.
>
>Now, to keep them out of drying gelatin sheets! ; )
>
>best regards,
>Phillip
>
>btw, the color and effect of the light you describe is very much
>like the UV units I use to photograph
>stained gels for research purposes. It's probably been covered on
>the list many times here but this
>type of output can be very damaging to the eyes. I know that you
>know this but thought I'd mention
>it for others.
>
>Sandy King wrote:
>
>>Recently a friend sent me information about the following site on
>>dust and static control.
>><http://www.modernsolutionsinc.com/dust/duststa2.html#Anchor-60134>http://www.modernsolutionsinc.com/dust/duststa2.html#Anchor-60134This
>>got me looking at the dust and static problem in my own printing
>>environment. I print with two different light sources: 1) a 1000
>>watt metal halide HID lamp and, 2) a large 48X32" bank of BLB
>>tubes. Both are used with vacuum easels and give very good, but
>>slightly different, results. However, the BLB set-up is
>>interesting, almost weird, because with this light, which is very
>>dark blue/purplish in color, every little speck of dust, lint,
>>dirt, skin flakes, hair, etc. stand out in a way that is difficult
>>to imagine if you have never worked with BLB light. Completely
>>different look from a bank of BL tubes I might add. OK, I was
>>really shocked by all the stuff blowing around and landing on the
>>glass of the vacuum easel during exposure with the BLB lights. I am
>>sure it is happening with the Metal Halide unit as well but the
>>color of the light does not reveal it as well. So, what I am
>>wondering is this. Is there any kind of electronic anti-static
>>device that one can attach to an exposing unit or vacuum frame that
>>would reject this trash, rather than attract it as is apparently
>>the case. Sandy King
This archive was generated by hypermail 2.1.5 : 08/07/03-03:34:50 PM Z CST