U of S | Mailing List Archive | alt-photo-process-l | RE: Carbon on glass with back exposure

RE: Carbon on glass with back exposure

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 current 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
> 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: mail@loris.medici.name>
>> Subject: Re: Carbon on glass with back exposure> To:
>> alt-photo-process-l@usask.ca> > Thanks Marek!> > A question about
>> exposure: how sensitive is the process to exposure> variations? 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.> > ...>