John Melanson (email@example.com)
Mon, 02 Aug 1999 09:11:08 -0600
It seems to me that the RH may not be as important as the total amount of
available water for the reaction. Perhaps we should define a factor, RPH,
relative paper humidiy, that is the percentage increase in paper weight due
to water. Maybe that is the most relevant number.
I terms of accuracy, a larger sheet or thicker paper would tell more
At least this measure would be consistant between various practitioners.
> -----Original Message-----
> From: Jeffrey D. Mathias [mailto:firstname.lastname@example.org]
> Sent: Monday, August 02, 1999 6:01 AM
> To: alt-photo-process list
> Subject: Re: Wet & Dry Exposure
> Gary Miller wrote:
> > ... But I would watch out for the + or - error in such a small weight
> > gain. This may cause some problems. ...
> Assuming the range is as John has seen, about 0.5 gram difference
> between dry and humidified, and if that represents say a swing of delta
> 40% RH, then I feel we MAY be able to get a ballpark figure. Getting a
> value +=2.5% RH (to the nearest 5%) is probably good enough for the
> effects we have been observing. BUT and IF: we don't know the
> relationship between the weight of water and the RH of the paper or
> coating. This may not be a linear relationship and will depend on other
> factors. And this will vary with the type of paper.
> The weight of water may be an informative parameter, however I have
> doubts if this can be readily converted to a value of RH. But then
> which parameter would provide for better control.
> My guess is that we will arrive at a standardized technique to reference
> moisture effects rather than a measurable value.
> Jeffrey D. Mathias
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:40:39