>In the fourth test there was no change, in size
I did six more tests and there were no further changes in size
the paper had for all practical purposes stabilised.<
I Continued paper testing this time trying out the following papers
a)Ingres Fabriano 90gsm
b)Hammer 4r 180gsm
c)Goldline Lanaaquarlle 185gsm
d)Fabriano Artistica 200gsm
e)Rives BFK 200gms
f)Hunnemuller 300gms
Each paper sample was soaked in cold water for 10 mins then dried with a
hair dryer.
In all cases the sample stretched beyond the original size when
wet then shrunk back smaller than the original size when dried, by the
following percentages.
a)1.00%
b)0.33%
c)0.33%
d)0.33%
e)0.33%
f)0.33%
which in the case of b) to f) was the same even though the paper weights
were very different
Although most of the papers seemed to follow a similar pattern, a) was the
odd man out this paper was very thin and was designed to be used as a paper
for contie crayon and chalks not really suitable for our processes it did
stabilise but kept moving around.
Conclusion
most papers shrank to the same extent independent of paper weight, thinner
papers expanded and shrank to a greater total amount, and are more fragile,
than thicker papers, which seem to be more stable, however thicker papers
take longer to dry out, which can cause trouble through water retention.
Drying is critical only when the paper is completely dry
does the paper stabilise.
A good method to measure this effect is to dry on a sheet of
glass that is cold.
What happens is that as the dryer dries one side, the moisture travels
through the sample and creates steam on the other, so keep turning and
moving around until the steam is no longer visible, the sample is then dry
and stable.
So where do we go from here.It seems that three wet and dry stages will
stabilise most papers,and the shrinking seems to be consistent when using
a number of different paper samples, but I need to do a lot more tests to
verify this.
I hope this info may be of use
pete
To get the best you must test :-)