What eb said Pat and yes, when the screens are burnt, dry, ready to go on press, just before adding the ink. I started doing some flatstock with wb and got in the habit. Never tried textile wb without the technique so I wasn't aware that it wasn't needed. Noted, but we'll keep doing it all the same, I think it makes sense to pre-charge the stencil with a little h20. My guess is the soap just helps it penetrate.