If you’re new to watercolor painting then you may be wondering what a watercolor block is and how to use it. I first saw a watercolor block when I was in high school. I couldn’t figure out why it was glued on all four edges until my art teacher demonstrated how to use it.
What is a watercolor block? A watercolor block is a pad of watercolor paper that’s bound on all sides with a coating of a rubber like material. You paint on the top sheet of paper and then remove it after it dries flat. To separate the painting from the block, insert a dull palette knife into the gap in the binding and run it around all four edges.
In this post, I provide all of the information you need to determine if a watercolor block is right for you. I explain what a watercolor block is and how to use it. There are also a number of tips that I provide that will help you to get the most out of your watercolor block.
The Advantages of Using a Watercolor Block
Watercolor paper has a tendency to buckle when it gets wet. One way to get watercolor paper to dry flat is to stretch it. This is somewhat of a tedious task, and a watercolor block will allow you to skip this process.
The process of stretching paper is an in depth topic that I may cover in another post. Basically, stretching watercolor paper involves wetting the paper and then you attach it to a board with staples. There’s also a special tape that you can use to tape the paper to the board. The paper shrinks as it dries, so it dries flat. When you paint on it, the paper is less likely to buckle. The paper will dry flat even if the paper buckles when you’re painting on it. A watercolor block provides some of the same benefits without having to go through the trouble of stretching the paper.
An advantage of using the block is that you can begin painting without any preparation–there’s no stretching the paper or waiting for it to dry. This is great for painting outdoors where you don’t have the time for stretching paper. It’s also not practical to carry around the necessary tools when you’re painting outside.
When you stretch watercolor paper by hand, you lose some of the paper along all of the edges. That’s because you have to secure it to a board with staples or tape. When you’re done, your painting will have staple holes along the edges, which you can trim off. If you’re using tape instead of staples, you can sometimes successfully remove the tape without damaging the paper. However, I find that it’s usually easier to just cut it off.
The watercolor block eliminates the need to trim the edges of the painting. You can paint right to the edges of the block. Some artists like to mask off a border around the painting with masking tape. This will leave a white border around the painting when you pull the tape off. You’ll want to use tape that has a low tack adhesive so you don’t rip the paper when you remove it. See the related questions at the bottom of this post for more information.
The paper in the watercolor block is less likely to crease or get dings in it because it’s backed by a rigid board. This is another reason why the blocks are great for painting outside. I throw mine in my backpack and don’t worry about damaging it. If you leave the painting on the block, it can also help protect it on your way home. Otherwise, you’ll need some sort of portfolio to protect your paintings as you travel.
How to Remove a Sheet of Paper From a Watercolor Block
If you look at the watercolor block, there’s a coating of a plastic or rubber like material around all four edges. Arches uses a black material which makes it easy to see. Many of the other brands use a clear material to bind the edges. Somewhere along the edge of watercolor block, you’ll find a gap in the rubber material. Arches places the gap in the center of the front of the block. Fabriano places it in the front left corner.
The gap is there so you can slip a dull palette knife under it and run it along all of the edges. This will separate the paper from the rest of the block.
You’ll want to be careful when you do this so you don’t cut into the painting by accident. I like to use a dull butter knife because it’s less likely to cut into the paper or scratch the sheet below it. These scratches may show up when paint over them in the next painting.
If you don’t have a dull butter knife, then a palette knife or letter opener may work too. One of my favorite instruments for separating a sheet of paper from a watercolor block is a guitar pick. A guitar pick is small and has dull edges and round corners. I like to pack one in my supply bag when I paint outside. It’s lightweight and it doesn’t take up much space.
The Disadvantages of Using a Watercolor Block
A common complaint about watercolor blocks is sometimes the paper separates from the cardboard backing, or the sheets split apart. When this happens, you lose all of the advantages of the watercolor block. To use the rest of the paper, you have to remove each sheet from the block and stretch it.
This Fabriano cold pressed watercolor block is separating from the backing board. It’s 12”x18” and I find the larger boards are more prone to splitting like this. Some artists try to paint a coat of acrylic medium around the edges to seal it, but I find this doesn’t work that well. I never have this problem with 9”x12” blocks, especially the ones from Arches.
Another issue with watercolor blocks is that you can only work on one painting at a time. Since the binding extends around all of the edges, you can’t work on the sheet below the current painting until you remove it. If you like to finish a painting before you move onto the next one, then this may not be a limitation for you.
You can also solve this problem by purchasing multiple blocks of watercolor paper. This is what I do, it also ensures that I won’t run out of paper.
A common criticism that artists have about watercolor block is that the paper isn’t as tight as it is when you stretch it by hand. This may bother a professional watercolor artist, but if you’re just starting out, then it probably won’t be an issue for you.
Advanced painters may like their paper stretched tight, especially if they use a lot of water when they paint. However, as a beginner, a watercolor block is a good choice because it will things easier for you. You can skip stretching your own paper and you can focus on painting instead. You can always learn how to stretch your own watercolor paper when you gain more experience.
How do you open arches watercolor blocks? Arches watercolor blocks are usually shrink wrapped. I remove the shrink wrapping by turning it over so the cardboard backing is facing up. Then you can cut through the plastic wrap without damaging the paper. The cardboard is thick enough that you won’t cut through it. Once you remove the plastic, you can to fold the paper cover back, but I don’t recommend removing it. The cover will offer some protection from any unused sheets of paper that remain on the block. Aside from dust, the cover should protect the paper from scratches, which usually show up when you paint over them.
Can you use masking tape on watercolor paper? Yes, but you want to use masking tape that has an adhesive that isn’t too aggressive. Look for a low tack masking tape for delicate surfaces. Another option is to try and wear out the adhesive before applying it to your paper. I sometimes stick it down to my workbench and remove it a couple of times. If you want to really weaken the adhesive, try applying the tape to an old shirt and then removing it. The tape will pick up some of the fibers, and that weakens the adhesive.
Don’t leave the tape on the paper for too long or you may also have trouble removing it without ripping the paper. It’s best to remove the tape if you know you won’t be working on the painting for some time.
What size is a half sheet of watercolor paper? A full sheet of watercolor paper is 22” x30”, a half sheet is 15”x22”, and a quarter sheet is 11”x15”. These are all based upon the Imperial full sheet, which is in inches.