[alt-photo] pre-shrinking paper

[Erich Camerling]

Dear members,
 From my own measurements with ARCHES PLATINE  I know that pre-shrinking 
has a little effect compared to sizing with gelatine.
                                                    
width                          height                      diagonal
                 1x preshrink            + 0,05 %                    - 
0,47 %                    - 0,15 %
                 1x  sizing                 -  0,26 %                    
- 0,57 %                    - 0,53 %
   1x pre + 2x  sizing                 - 0,54 %                     - 
0,76 %                    - 0,77 %
How did I do this measurements :
I took 5 sheets of brand new ("virgin") Arches Platine (19 x 28 cm) 
(~7,5 x 9,8 inch.(For members who still love that archaic unit)).
In every corner of every sheet I put a little hole with a pin.To easily 
find again that little hole after every treatment I drew a small circle 
around every hole with a pencil.Then I measured very precise all the 
distances in every sheet (4x along the edges : left,right,above, under ; 
2x diagonal ).
I gave three sheets a preshrink (60 min. 50 deg.C) .(Archaic : 122 deg 
F.) ,dried these sheets and measured the distances again (P).
I sized two sheets from these three sheets,dried them  and measured 
again (P + S).
One sheet from these two sheets I sized again etc.  (P + 2x S).
I sized the two remaining "virgin" sheets,dried them etc. (S).
And one of these sheets I sized again etc.  (2x S) .
After comparing the results my conclusion was : sizing gives the highest 
shrink in this (=my) situation.
Everyone can do this test for her (his) own paper.  Maybe you come to 
comparable results and then you can stop preshrinking.
That will save a lot of time for the future.
Kind regards ,
Erich