The best tape for creating straight edges is “Watercolor Washout Tape” which looks like a big roll of cellophane tape but it’s thicker and stronger. It costs more than the blue painter’s tape from the hardware store but gives perfect edges if used correctly. Using correctly means making sure the tape is secure on the paper by smoothing with a burnishing tool or finger over the tape. One way to get a double use from the tape is to only put down half a side. After it’s taken off the paper the tape can be flipped around and the clean edge can be put down.
Sometimes a tube of paint gets hard, maybe after not using it for months, and you are ready to toss it out. Don’t! It can easily be salvaged and used. Take a single edge razor blade or xacto knive and cut off the ends of the tube. Then slice down the length of the tube to open it up. The dried paint will usually pop out. You can also dig out paint from the cap end that was cut off. Then you can use it either dried, like pan paints; or you can put it all in a small jar (like a prescription pill container or baby food jar), fill it with hot water to barely cover the paint, and put a lid on it. Usually the latter takes about a week for the paint to soften. And voila! No wasted paint.
Inexpensive flat bristle brushes from hardware stores can create grasses and lines. Onion, orange, grapefruit bags cut up can give a “pineapple” texture. Sponges, toothbrushes (which are also used for spattering by moving your finger along the bristles), mesh screens, and other kinds of screens can create texture. Even using a broken tree stick dunked in paint can give scratchy uneven strokes. Any item that has holes can create textures on dry paper. Items that have indentations, like paper towel designs, work well on wet paper. Go give it a try. And wear a smock.
Any container can be used for water for cleaning brushes. Make sure your container is filled with water as high as you can fill it without spilling. Why? Often, a painter is in a hurry putting this and that color on the paper. If the brush isn’t totally clean because you’ve not managed to fully dunk it in the water container, some residue paint will still be on it when you go to your next color and then voila! Your color intentions are not what you think they should be – you’ll be putting down 2 colors instead of one!
Also, an extra container of clean water is helpful if you need to do clean washes on the paper. It just saves an extra trip to the sink.
I’ve tried them all. The best is Jack Richeson Shiva. Not expensive. It has a pinkish cast so when dry you can see it. It also dries with enough film so you can easily pull it off instead of scrubbing.
Store the bottle with duct tape around the cap and set it upside down. If the mask gets hard, pull out the hard stuff on top (like latex house paint) and stir before using. You can always add a drop or two of water to thin the mask if it has gotten too thick.
Use an old watercolor brush. Dip it in liquid detergent and put on mask. After using the mask, instantly wash the brush. The brush can then be used again for another mask. Usually after 3 times, the brush has enough dried mask on it and you have to trash it. If you don’t put detergent on the brush, you’ll only get a one time use.