Prevent buckling without stretching your paper

Here’s a method for preventing your paper from buckling while you work that does not involve stretching it: working on paper that is saturated from the back.

This method is easier for those who don’t stretch paper because they have a hard time operating a staple gun.

But, the main reason I use it is that it also has the advantage of dramatically slowing down the dry of washes, giving you more time to get back in and soften edges or paint a large wash around a complicated shape. This is great for florals and portraits, where you often need to create a controlled, soft value or color gradient to show a gently curved surface.

Fair warning, though: this method isn’t entirely hassle-free. Be sure to watch all the steps. You need to take a bit of care with how you leave things to dry between work sessions to avoid a danger of unwanted blooms.

Every method for dealing with paper buckling has advantages and disadvantages. There is no method that allows you to simply throw down a piece of watercolor paper, paint with all the water you want, and never encounter any buckling. If there were, we’d all already be using it!

What you need for this method

Note: There are no affiliate links in this article. I’m not in the business of advertising for other people’s products. The links below are just so you can see examples of what I’m talking about. The products linked are ones I’ve used, so I can tell you they are acceptable quality, but they’re not necessarily the best or cheapest option.

You’ll need a smooth painting support that is impervious to water, such as

a piece of corrugated cardboard, completely covered with clear packing tape (see this video for instructions)
a piece of corrugated plastic (Coroplast); this is often sold in hardware stores for making yard signs
Gatorboard (This is like foamboard, but has a waterproof wood surface instead of paper. There are a lot of knock-offs that aren’t waterproof being sold online. I recommend you buy from an art supply store to sure you’re getting actual Gatorboard. It’s a bit expensive, but lasts forever. I’m still using the first piece I bought over 20 years ago.)
a piece of plexiglas or tempered glass
a nonporous, non-textured cutting board (sealed wood or smooth plastic)
wood or hardboard sealed with a waterproof coating (e.g. spar varnish, marine polyurethane), or covered with waterproof shelf liner

You’ll also need a couple of puppy training pads, like these. The ones I’ve linked to are the extra-large size you’d need for a full sheet of watercolor paper. If you paint smaller, choose a smaller size.

The ones I’ve linked to are disposable, but for watercolor painting, you can let them dry and re-use them for a looong time. (I bought a package of 30 about three years ago, and it still has 8 or 10 left.) If you prefer a washable option, you can try these. I bought some of the washable ones to try, and they are fine for catching drips when I’m pouring or spattering. But for the technique in this video, I’ve found the disposable ones work a bit better. They seem to trap the water faster.

I usually rotate three or four, so they have time to dry between uses. They get stained, but the color seems to stay trapped in the inner layer. But just to be on the safe side, I reserve one for use with only clear water, you’ll see why in the video).

Finally, you’ll need a large, soft brush that carries a lot of water. I use a hake. You could also use a large mop, mottler or sky wash brush. You could also use a sponge, but I find it harder to release a lot of water exactly where I want it with a sponge, so I stick to a brush.

If you haven’t seen the “droplets” technique for trees, you can learn more about that in this video at timestamp 8:04. (Note: The Holbein spray bottles we used to use for this have changed and no longer work for this technique. I haven’t found another one that works consistently, so now we all have to just try different spray bottles until we discover one that makes droplets instead of a fine mist. I’ve had pretty good luck with travel-sized “trigger” style spray bottles intended for hair products.)