How To Stretch Watercolour Paper

Oh bane of my life. Oh job I hate more than anything else with regard to painting! Yes, stretching watercolour paper. I actually only hate it because it takes time and means I need to plan ahead and it sometimes means I can't be spontaneous, it's actually pretty easy to do! Someone asked me yesterday on Twitter about this so I put together this video showing how I personally do it. I've also curated some timings for different papers so that you can get your soaking times right. NB: if when it has dried, your board has bowed or buckled (yes, paper is stronger than boards, weird huh?!), you will need to cut the paper free and stretch it again on a stiffer board, because it hasn't actually stretched properly. You'll need to be careful with it - once it's been soaked once, a second soak can ruin the sizing, so you may be better off testing your board with cheap paper first and making sure it's strong enough - thicker papers are more likely to cause issues with this.

Personally, I do stretch 425gsm (200lb), 535gsm (250lb) and 638gsm (300lb) papers - they do benefit from it if you like to paint a lot of washes or use mediums.

Caution re: masking fluids: sometimes after stretching, even if they survive washes and painting, the sizing can be weakened enough that masking fluids can rip the paper - as such, if you use masking fluid on stretched paper, just be especially careful when removing it and don't leave it on for more than an hour or so.

Chemical pulp papers (e.g. Bockingford)

300gsm or higher (140lb or higher) - 8 minutes - some of the really heavyweight papers need 10 minutes but few need more.
190 to 300gsm (90 to 140lb) - 3-4 minutes.
150gsm or lower (72lb or below) - 2-3 minutes - maybe even less.

100% cotton papers (e.g. Langton Prestige, Saunders Waterford, Millford)

Per the above but depending on humidity and how the paper has been stored, you may find it needs a little less time - experiment.