[Alt-photo] Re: UV light box
ejnphoto at sbcglobal.net
Thu Mar 6 00:40:07 UTC 2014
OK, Here is what I have. Super Actinic and BLB bulbs alternating in a box
that has a bit over 3/16 between each tube. I can cover an area of about 44"
x 30 " without much problem. It is not just the spread of the light, but
over all intensity. I did not run exhaustive test and this was a basic
design that goes back to Nadeau's book on platinum 1st edition.
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Sent: Wednesday, March 05, 2014 5:53 PM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [Alt-photo] Re: UV light box
Just a FYI,
The Inverse square law does not apply well to tubes. I believe it is a
point source sort on measurement. Find a light meter and measure under
your assembly. While most likley not detecting UV it will still give a
reasonable indication of fall off from the available light it can see.
Should correlate with UV drop off.
On Wed, Mar 5, 2014 at 3:18 PM, Bob Cornelis <bob at colorfolio.com> wrote:
> Thanks for the response, Charles.
> I went ahead and ordered 7 of these bulbs (sort of on a deadline to build
> this box), thinking I'd put them at least 4 inches apart giving me a
> coverage area of 24x28. I've heard these bulbs have a good, even "spread"
> so I'm hoping the 4 inch spacing is fine. I guess I can always buy more of
> Other opinions welcome!
> On Mar 5, 2014, at 2:06 PM, Charles Ryberg <cryberg at comcast.net> wrote:
> > I thought you would get answers from people with more experience that
> I--but so far, no.
> > I use the same or similar tubes. I have 8 tubes spaced over 12 inches,
> which is almost certainly closer than they need to be. I can print 11 x
> with this and can't see the need of anything larger. I have used a unit
> Southern Oregon University which had 4 ft tubes spaced about 6 inches
> and at least 8, probaby 10 or more inches from the paper. It worked well.
> It was open on three sides so many students could insert their projects at
> one time and could remove them without disturbing other's.
> > My only question about yours is that you hope to print a 24 inch long
> image with 24 inch long bulbs--I'd guess you will get fall off.
> > Charles Portland OR
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