Art Chakalis (achakali@gcfn.org)
Tue, 09 Nov 1999 10:34:38 -0500 (EST)
Donnay,
I worked with a projector for a while though center to edge light fall off
was a bit high and registration for multiple exposures can be difficult.
It does work and with a little effort I came up with a simple way to make
register multiple exposures. I made a wood stand to mount both the
projector and a screen so as to keep the setup constant and aligned. The
projection screen was metal (as in steel). I then took a couple of
different sizes of speed-ez-els and put magnetic tape on their bases which
allowed them to be placed and moved about the steel screen. This
arrangement, though far from perfect, made multiple exposures possible.
I have one better idea for you, though it was more than an evening
project. I converted, and still use, a Durst 606 to handle an ELH lamp.
It is a projector's lamp and modified condenser system mounted within the
head which is all metal (helical focus versus a bellows). To minimize
vibration, cooling air is fed through a hose from a remotely mounted
blower. The lens is Nikon 50mm f2.8 enlarging lens. It has enlarged up to
an 11x14 but smaller sizes maintain a better image quality.
Having said all this, I believe that contact printing using full size
negatives can achieve a higher quality print. I built the enlarger to
simplify some experimentation and testing but it does provide good results
in smaller print sizes.
The Fresson enlarger is reported to use a carbon arc lamp which requires
some special safety considerations. I have been told that large prints
can require several hours of exposure. Having seen some very large prints
(from recollection maybe 30"x 40") the resolution looked quite good to my
eye.
Sincerely, Art
Art Chakalis
Columbus, Ohio, USA
On Tue, 9 Nov 1999, donnay thierry wrote:
> > Interestingly enough, they say that they use a high-powered UV enlarger,
> > instead of using intermediate contact negatives. I wonder how will all
> that
> > UV light affect your color slide. If I were you, I'd send a duplicate...
>
> Some interesting news for the gum-printers or carbo-printers. Dichromate is
> sensitive enought to work with a slide projector. No need to use
> intermediate contacts negatives if you're doing "small format" (I mean A4
> maximum) : 20 minutes exposure for a well contrasted 24/36 negative.
> But I have to confess that I heard about this 'discovery' a few weeks ago
> and that I only did tests. I can't produce a perfect result at this moment,
> but it's working perfectly. Only disadvantage : long long exposure time. But
> I'am now customising my slide projector and putting an UV lamp into it
> (Philips HP 125w).... I hope it will reduce the time of the exposure.
>
>
> Bye,
>
>
> Thierry from belgium
>
>
> Alt-photo site :
> http://www.photogramme.org
>
> egg prints :
> http://www.photogramme.org/textes/gal_th_oeuf1.htm
>
> gum prints :
> http://www.photogramme.org/textes/gal_th_gomme1.htm
>
>
>
>
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