More Sizing experiments: "Flash" sizing with a summer recipe of nikawa and alum.

 
I did manage to sneak into the studio long enough to set up and size a dozen sheets of paper.  Now they're hung out to dry and will need to "settle" for a week or two before I can test the paper to see if this ratio was suitable for these papers, in this weather.  It wasn't perfect. The big brush works, but it tends to dump a lot of size at the beginning of the stroke across the paper, and much less at the end, and getting that right takes practice and changes with the papers. Since I was trialing a few sheets of several different papers, when I sort of got the hang of it for one paper, I had to switch to a new paper. In a couple, I had to go back over the sheet a second time--where the brush had skipped or left a puddle and on the heavy cellulose paper--I got some wrinkles that will be permanent (and those sheets will have to be cut down to smaller sizes to get rid of the damaged parts).  After a couple of weeks, I'll have a trial printing of a simple image on small pieces of each paper to see how much the absorb or resist the color.  The fish-poacher and small hot-plate worked well for warming the size, I'm still not sure if I did a better job with the bigger brush.  As I mentioned above, ideally, each paper will have a "best" recipe for size for moku hanga, and this ratio of glue and alum will change with the season (more glue in the summer/less in the winter) and the less alum added the better. I tried this recipe a few years ago (a total disaster) as it was on cheap, locally available, mostly pulp papers with just a small amount of kozo fiber and I ended up just gluing all the sheets together.  With nearly the same recipe, on good almost 100% kozo papers, the size goes on smoothly (mostly) and I could see it got absorbed into the paper almost immediately. I'm curious to see how much my inept handling of the brush will affect the final paper, and try to tease out how much is my glue/alum ration and how much is just my inexperience with the sizing brush (dosa bake).

All hung up to dry: Torinoko  Kozo, Kozo thick natural, Hosho Professional, Kochi white.

Here's a buckle/kink that won't go away.

Painting (sizing) with a Broad Brush

Sometimes, even without overly generalizing, you really do need a broader brush; especially if you want to size Japanese washi.

Those who have followed my occasional posts about my attempts to home-size Japanese paper to make it suitable for printing know that the biggest problem up to now has been finding suitable papers but that's slowly working itself out now that better papers are getting easier (a little) to find either outside Japan, or within it thanks to e-commerce or reliable paper sellers of quality papers in the US, Canada, and abroad (Hiromi Paper, The Japanese Paper Place, The Paper Connection, McClain's (although they sell high quality pre-sized papers for moku hanga), Intaglio Printmakers (UK) and Les Papiers de Lucas (France),  and probably others I haven't found yet. 
But the biggest practical problem remains actually sizing the paper; figuring out suitable glue and alum ratios and recipes for my climate and the paper I'm trying to treat. (Size, or dosa in Japanese, is the mixture of alum and animal glue that is added to the paper to make it less absorbant).
In Japan, the paper was traditionally sized on one or both sides of the paper and IDEALLY, the warm glue was applied with one quick pass over the sheet of the paper with a fully loaded brush. With a small brush it's hard to cover the entire surface without overlapping the edges from the previous pass and where the brush passes twice (or misses entirely) will leave paper unevenly sized that will show up when the paper is printed.  Getting the mixture onto the paper evenly without buckling or crinkling the paper or leaving gobs of size that will act as a resist isn't that simple a task but it's made easier by a bigger brush that holds enough glue to make it across the entire sheet in one go.
The only brushes I've been able to find actually made for applying size are pretty small at 2 to 4 inches across, water brushes for dampening paper are a little easier to find and I purchased a couple of 6" brushes a few years ago with the intent to try to put them together with a jig to allow me to create economically a brush sizing brush. These are two "economical" Chinese sheep wool "water" brushes (mizu bake) that I'm going to be using for adding  the glue and alum (dosa) to unsized paper to render it a little bit resistant to absorption and hence suitable for moku hanga, watercolor woodblock printing.
A real Dosa Bake or sizing brush--of this width, even if they were available-- would cost a few hundred dollars. This will end up costing about $50; since I got the two 6" brushes on sale from McClains Printmaking Supplies some time ago.

David Bull posted photos of an Artist (in France?) who had actually already done so and the photo was just like what I had imagined trying to do--and he was home-sizing his paper with a large brush with two smaller ones glued onto it and with good results.  David also confirmed that he too has made several and that they work well enough if one shaves back the wood to allow the brush parts to line up closely--so I decided to go ahead and try to put one together from the brushes I'd previously purchased.

These two brushes are the same size and from the same manufacturer but they're not identical so I had to adjust them a bit so the brush ends would line up and remain flush. The two edges of the wooden handles were shaved down with a sharp chisel so the brush portions pushed against each other and with care to make sure the sheep's wool lined up as well as was possible they were glued and clamped one at a time with water-resistent PVA glue.  

I'll let this thing dry for a bit and have a go at sizing some 100% Kozo paper that I bought earlier this year. My new brush is 14" across, so I can size in one pass a sheet of about 15" X 30".  A trip to the basement revealed an old aluminum fish poacher and armed with my food warming, hot plate (1970's), Aluminum Poacher (60s?), and "new" 14" dosa bake I'm ready to try another round of sizing Japanese paper for moku hanga printing.  I'll let you know how it goes.

Various water and sizing brushes that I've accumulated over time.