Soaking & Stretching Techniques

Soaking in water and stretching is recommended when lighter weight papers are used usually 150g/m², 190g/m², 300g/m², because
these papers will move and buckle/cockle when water is applied.


Why does the paper move?

The application of moisture to the sheet causes one side to expand slightly while the other side remains dry, and does not expand. To counteract this expansion on the wet side, the paper bows and buckles. This is very unattractive for the finished painting and
difficult to work with because the paint will pool within the waves of the paper.


How to soak and stretch watercolour paper

1)Soak a sheet in a tray of clean cold water for:
   150g/m² (72lb) - 3 minutes
   190g/m² (90lb) - 3 minutes
   300g/m² (140lb) - 8 minutes

Take care not to touch the area you intend to paint (the paper is fragile when wet and finger marks will show up in the wash).

2) Drain the paper and place the soaked sheet on a sturdy board/ Marine Ply
3) Blot any excess puddles of water with a clean paper towel.
4) Wet some gummed tape with a sponge or large paint brush (do not soak), and place around all four edges of the paper, and
    leave to dry on a slight tilt.
5) Leave the paper to dry overnight. When dry the paper will be stretched tight on the board and when water is added with the
    paint the paper will not move.


Important

When soaking the paper check for residue detergents found in areas like baths, kitchen sinks. These detergents attack the sizing
causing the paper to become very absorbent and unusable.


Trouble shooting

Tape pulls away from paper when the paper is drying

- It is possible the gummed tape has been wetted too long removing too much glue.
- There isn’t sufficient glue on the tape to hold the paper tight when drying.
- There is a problem with the absorbency of the paper caused either accidentally or during manufacturing, which has caused the
   paper to soak up too much    water that makes it difficult for the tape to stick to the paper.

The paper acts like blotting paper after soaking, but is fine unsoaked

- The most likely explanation is the paper has been contaminated with detergents.
   Dark marks are appearing in the wash

- Usually dark marks that appear in the wash are the result of finger marks when handling the paper.
  Thin white lines are appearing in the wash

- Thin white lines are usually caused by a puddle of water being left to dry on the paper. The puddle dries leaving a 'tide mark' which
   shows up as a white line after application of a watercolour wash.

The paper isn't as strong after soaking and stretching

- If the paper is soaked for too long the gelatine surface can be washed from the sheet leaving the paper weak and subject to tear.


How to avoid soaking and stretching

- Use a heavier weight paper; 425g/m² or above should not require stretching. The paper is thick enough to withstand the moisture
  applied to it without buckling/cockling too much.