Re: sun vs exposure unit

One could also use a light integrator in printing with the sun. It
has been done before.

Sandy

>The trick with the sun is that the UV portion of exposure isn't
>consistent.
>
>A possible solution could be to use a printing out process - like
>cyanotype and a step-tablet to measure the cumulitive UV exposure.
>
>You have a small printing frame with a split back, or maybe just tape
>the cyanotype and step-tablet. Every few minutes shield the frame from UV
>- open the frame and see how many steps have exposed.
>
>You would have to do some testing to see "how many steps" are needed to
>expose your photopolymer plate. But once this is established you may be
>able to get consistent exposures with the sun.
>
>can get step-tablets from http://www.stouffer.net/TransPage.htm
>
>Others have done the same thing on a much simpler scale - putting a dime
>on a piece of cyanotype and gage the exposure by picking up the dime and
>gaging the exposure by the difference between the unexposed cyanotype
>under the dime and the exposed cyanotype.
>
>Gord
>
>
>
>
>On Thu, 26 May 2005, Barb wrote:
>
>> Actually I live in Texas, so ok there. Also, am doing something a bit
>> different. I'm exposing photopolymer for art rubber stamps. I have an old
>> graphic arts light table that I use as an exposure unit (for both photo
>> processing and the rubber stamps)--I just replace the regular flourescent
>> bulbs with UV bulbs... but the bulbs were damaged during a move and I need
>> to be working between now and the time the new bulbs arrive. I really
>> appreciate your input!
>>
>> One question: what process are you using?
>>
>> Also, once process is posted, would someone please post their own times
>> with an exposure unit for the same process? That would be so helpful!
>> thanks again,
>> b
>>
>> At 03:57 PM 5/26/2005, you wrote:
>>
>> >I have to rely on the sun. I'm in Phoenix, so you'd think we'd have a lot
>> >of that, wouldn't
>> >you? Unfortunately it is unpredictable due to high thin clouds and
>> >haze/pollution. In
>> >December and January, there's often a cloud cover, and it can't be
>> >predicted, so coating
>> >paper for a schedule involves a crap shoot. Also, between mid May and
>> >about October
>> >1st, my brick-enclosed patio gets into the 150+ F degree range. The risk
>> >of melting
>> >things like, oh, negatives and Pictorico seems to be very real. I can't
>> >compare to UV
>> >because I'm still building my UV box; but times are fine, in the range of
>> >2-4 minutes
>> >depending on negative material, negative density, and print medium. Real
>> >film negs take
>> >longer, printed negs can be much shorter. The main problem with sun, even
>> >here in
>> >Arizona, really is variance - not only the season and the intense summer
>> >heat, but also
>> >the longer exposure times needed before about 11AM and after about 2PM -
>> >longer then
>> >and difficult to gauge. It's a real PITA. That's why I'm working on a UV
>> >box; but the sun
>> >is perfectly doable if you set your mind to it and happen to live in
>> >Arizona. :)
>> >
>> >Mike
>> >
>> >On 26 May 2005 at 14:50, Barb wrote:
>> >
>> >Date sent: Thu, 26 May 2005 14:50:20 -0500
>> >From: Barb <rubyslpr@sbcglobal.net>
>> >Subject: sun vs exposure unit
>> >To: alt-photo-process-l@sask.usask.ca
>> >Send reply to: alt-photo-process-l@sask.usask.ca
>> >
>> > > Does anyone use the sun rather than an exposure unit? I was just
>> > > wondering if anyone can tell me how it compares (time) to UV exposure
>> > > unit. If so, please include your location and the time of day you do
>> > > your exposures? Thanks so much, Barb
>> > >
>> >
>> >
>> >
>> >
>> >
>> >
>> >--
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>
>---------------------------------------------------------
>Gordon J. Holtslander Dept. of Biology
>holtsg@duke.usask.ca 112 Science Place
>http://duke.usask.ca/~holtsg University of Saskatchewan
>Tel (306) 966-4433 Saskatoon, Saskatchewan
>Fax (306) 966-4461 Canada S7N 5E2
>---------------------------------------------------------
Received on Thu May 26 19:59:39 2005