I did not know about the local UV index value, should be quite helpful.
I find the making of carbon tissue quite fascinating and easy to do. Glass is such a nice substrate for tissue as it stays flat and is quick and consistent to sensitize. Contrary to what you think it goeas quite fast once you get started. The limiting factor is how quickly the gelatin sets at your condition.
The biggest think is use of jet dry detergent. It eliminates the bubbles from the gelatin mix and allows to pour perfect tissue every time.
Kepp us posted
> Date: Fri, 4 Jul 2008 08:42:14 +0300
> From: email@example.com
> Subject: RE: Carbon on glass with back exposure
> To: firstname.lastname@example.org
> Thanks Marek.
> Since making carbon tissue is quite burdensome (when compared to the
> simple task of coating paper with a brush and then letting it dry for a
> couple of minutes), I wanted to know if there's a special knack... Thanks
> for the tips about clouds and sun's path!
> For exposure (+ digital negative calibration), I plan to use our local "UV
> Index" value. (Accessed through internet, given in a pretty precise manner
> like 9.8... Data is pseudo-actual since readings are made every 5
> minutes.) The index is linear, therefore I will just define and convert
> the times using the UV index as a factor... The station that takes the UV
> radiation readings is about 14 miles away of my curre
nt location, so I
> hope there will be not much variation between there and here. (Such as;
> clouds over there, clear here and v.v.)
> I know about carbon and did some test prints before... (Thanks to Sandy's
> book + the workshop we took from him few years ago in Istanbul.)
> 3 Temmuz 2008, Perşembe, 9:22 pm tarihinde, Marek Matusz yazmış:
> > Loris,
> > Carbon prints were made routinely at the turn of century with sun
> > exposure. We are not inventing anything new here. To keep exposure
> > variations to minimum try to make prints at the same time each day. Make
> > sure there is no cloud in the sun's path during the exposure. That will
> > ruin the print as the sharp shadows will disappear. Face the print to the
> > sun and align it perpendicular to the sun's rays to keep shadows as short
t; as possible. I guess it would be good to just record light intensity with
> > a lightmeter. Integrator might be OK, I do not have and never used one.
> > Exposing film test strips (traditional silver film based) is a great way
> > to learn carbon. It will also allow you to pick negative density that you
> > like. You already know how to translate this to a digital negative.
> > Exposure is tied to dichromate concentration and negative density, but 10
> > or 20 % variation will have little effect.
> > Best of all read some good literature on carbon.
> > Marek
> >> Date: Thu, 3 Jul 2008 11:59:45 +0300> From: email@example.com>
> >> Subject: Re: Carbon on glass with back exposure> To:
> >> firstname.lastname@example.org> > Thanks Marek!> > A question about
> >> exposure: how sensitive is the process to exposure> varia
tions? How did
> >> you calibrate your negatives for the process? How do> you manage to
> >> decide the correct exposure time? What is your procedure? Do> you use a
> >> light integrator?> > Regards,> Loris.> > 28 Haziran 2008, Cumartesi,
> >> 11:31 pm tarihinde, Marek Matusz yazmış:> >> >> > Carbon on Glass (Back
> >> Exposure).> >> > ...> > Walk outside, remove the top black cover and
> >> expose. 1-2 minute of direct> > sun is a good start for testing.> > ...>
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