U of S | Mailing List Archive | alt-photo-process-l | Re: Yellow tents and UV (was: outdoor gum demo)

Re: Yellow tents and UV (was: outdoor gum demo)

7 minutes is not short at all. There should be another explanation...

Controlling with a densitometer shouldn't be necessary as long as you use
negatives with the same DR (or the same negative), the printing parameters
are the same and you get equal highlight detail (or same number of steps)
- which would mean that you indeed gave enough / comparable exposure.

To be able to compare (UVB weighted as I get it) UV index values with UVA
radiation / printing times in a sensible manner, the atmosphere has to be
clear. (Plus, naturally, other printing parameters should be same or
pretty close.)


22 Nisan 2009, Çarşamba, 9:06 am tarihinde, Paul Viapiano yazmış:
> Loris...
> I observe this with pure palladium printing...7 minutes is my time.
> Now, it's purely anecdotal and not scientific because I don't measure
> reflective densities of wedges with a densitometer.
> Paul
> ----- Original Message -----
> From: "Loris Medici" <mail@loris.medici.name>
> To: <alt-photo-process-l@usask.ca>
> Sent: Tuesday, April 21, 2009 10:22 PM
> Subject: Re: Yellow tents and UV (was: outdoor gum demo)
>> Which process is that and what was the exposure time? I did notice a
>> difference (albeit not linear as I first predicted - have to work on
>> this)
>> with traditional cyanotypes. Maybe it's because at fast printing times
>> it
>> could be harder to notice any difference and/or self masking plays a
>> significant role... ???
>> Anyway, I'm ready to eat my assertion (and go to the corner on one leg)
>> if
>> someone comes up with an quantitative explanation to why giving the same
>> source (the sun) UVA intensity remains the same whereas other types of
>> irradiation seems to change intensity.
>> Regards,
>> Loris.
>> 22 Nisan 2009, Çarşamba, 5:36 am tarihinde, Paul Viapiano yazmış:
>>> Remember when we were talking a little bit re: this on the Hybrid
>>> forum?
>>> So far, I've noticed no change in exposure times from UV Index 4
>>> through
>>> UV
>>> index 9 when exposing via the sun...
>>> Paul