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Sizing

Materials and Supplies

 gelatin can attract silverfish

Gelatin Sizing from Helen Hiebert 

1 3/4 oz. Knox gelatin (7 pkg.) 
2 quart cold water 
dissolve in cold water 
let sit at least 10 min 
heat to just under a boil 
keep hot to use.

Methyl cellulose
Methyl cellulose seems to shrink and collapse in drying. Cast pieces from pulp internally sized with it can dry to a bony, craggy version of the mold design.
good glue for adhering sheets together
useful as a hardener but many believe that its use as a hardener is quiestionable
Do not use with a short fiber if you plan to later paint with a waterbased paint.  The waterbased paint will bleed through and the piece will becom limp
Ketene Dymer
An internal sizing of ketene dymer, on the other hand, preserves the plumpness of the pulp in drying. Used as a surface size, it keeps more of the surface treatment on the surface. It has to be diluted about half and half with water unless a shiny, plastic look is the goal. Watercolor tends to bead up on a ketene dymer surface, and some adhesives will not stick to it. 
Gelatin
Gelatin size can improve the strength and flexibility of paper 
CMC
some believe that this has yellowed their wrk.  SOme attribute CMC with creating a slightly plastic sheen to the surface of their work.  Maybe poor quality CMC causes this. 
Other sizes
Other sizes that work but attract vermin are wheat paste, rice starch and rabbitskin glue. White glue (Elmer's, e.g.) also works, but it seems to dissolve unevenly (for me) and create splotch problems for painting. Some people claim they use laundry starch successfully. 

The polymer sizes that eliminate the necessity of framing paper behind glass also resist or mottle paint, and make the paper look a bit plastic.  Obviously, any strong irreversible adhesive, or even a strong methyl cellulose solution, mixed in with pulp could conceivably glue the paper to the mold, ruining both project and mold. 
Blair Matte Acrylic has proven to be satisfactory Rice, wheat and gelatin size make papers attractive to bugs or fungal attack when humid

Sizing is added directly to the vat (internal) or applied to the sheets after formation (external). Both methods have their benefits, and some papermakers even use a combination of both techniques. Internal Vat Sizing
Internal sizing is an easy way to apply a coating to individual fibers, but still allow for some absorption of oil or water based ink or dye. All the paper made from one batch of pulp is equally sized. 
 
TWINROCKER INTERNAL SIZING   Sizing reduces the absorbancy of paper which is naturally absorbent.  to lessen or prevent bleeding and feathering of watery media.  Sizing also protects the fiber from oily media as well as dirt and pollution.  Twinrocker sizing is a pH neutral liquid size an alkylketene dimer, often called just "dimer", in concentrated liquid form.  It is used by simply diluting it in water and adding it to the pulp before papermaking.  USE:   37ml per kilo of dry fiber (3-1/3)tsp.,lb).  Measure 10ml or 1T.sizing per 10oz. dry fiber (1 sheet of cotton linters).  Sizing can also be used in greater concentrations and as a surface sizing on dry paper.  HARDENING:   Twinrocker Internal Sizing is an alkylketene dimer.  It becomes effective "hardens" or "sets-up" after the paper is dry, wither with heat, 200 deg. F. or with time, about 2 weeks.  REFRIGERATE:  Do not freeze.  Shelf life approximately 9 months.  The refrigerated shelflife is 12 months.  SAFETY: 
Contains epichlorohydrin, which is hazardous in its concentrated form before adding to pulp.  Wear safety glasses when mixing.  Safety data sheets available.  AVOID CONTACT WITH EYES, SKIN, OR CLOTHING. 
 
External  Sizing (Sheet)
External sizing is more time consuming, but has some advantages. Individual sheets can be sized differently for different uses. Surface sizes do not envelop individual fibers but add a protective coating to the sheet itself, inhibiting any absorption or bleeding. While this is a helpful quality for calligraphers, some do not care for the appearance of handmade sheets with too much surface sizing. 

Apply external sizing to well-dried paper using one of three methods: 
• painting - Use a large soft brush for quick application
• spraying- a simple plant sprayer if the size is fairly thin so as not to clog the sprayer
• tub sizing- run dry sheets through a tray of sizing liquid, or soak them in the tray for several minutes followed by a light pressing
 

•  2-3% solution of gelatin < mix 3/4-1oz (20-30g) gelatin to quart (liter) of HOT water.  Stir until dissolves. 
• put solution into a shallow tray 
• immerse paper < 1 at a time or in a stack 
• there must be enough size in the tray to cover the sheets completely 
• use wooden  dowel <approximately 1/2" dia) to remove the paper from the sizing bath 
• stack the sheets. no felts in between 
• one on top and bottom of entire sheet 

  If you are going to tub sized already dry paper, it is best to leave sheets to mature for several weeks before sizing.  If you wait the sheet is stronger, more stable and less likely to disintegrate in the sizing solution.  Can apply by brush, airbrush or tub. 
• Internal - added to pulp during last minutes of beating 

• PRESS gently to force the size through the sheets 
• If you catch the excess size, it can be reused. 
• restack sheets so that middle ones are on outside.  NO pressure. 
• Repeat each time you are changing the position of the paper until enough moisture leaves and paper is easier to handle. 
• Remove the sheets carefully and dry according to method preferred (by you). 
• It is good to keep the gelatin warm - approx. 122 degrees. 

• FINISHING 
• producing the final surface texture:  rough, smooth, gloss, etc 

Camellia leaf is sometimes rubbed over the top surface of gap paper while still on drying board.  This shines the top side.