A watercolour is made on paper that is specially made for it. You have study quality, and then you have top quality. There are quite a few manufacturers on the market and every self-respecting manufacturer has study paper and top paper in their range. Watercolour paper is next to the paint a basis for making good watercolours, these two are inseparable. On inferior paper you will never get good results, and that is a waste of the time and money you have put into it. This is usually the reason why people drop out.
You can buy watercolour paper in different sizes and designs. There are loose sheets, blocks with loose leaves, blocks glued on four sides, even rolls. The weight of watercolour paper is expressed in grams per m2. This can vary from say 150gr to over 600gr. (Technically that is cardboard) Usually the advice is given to use paper of minimum 300gr/m². My experience shows that paper of this weight works pleasantly. Inferior paper that is too light and of which the composition is not as good, will wrinkle if you use wet-on-wet techniques on it and the paint will do unexpected things with stains and hard lines as a result.
Water colour paper can be made of 100% cellulose, a mixture of cellulose and cotton, and 100% cotton. The best types of watercolour paper contain no acids and no optical brighteners and are also ageing resistant. Watercolour paper comes in different structures on the market and is referred to as follows. This applies whether the paper is cellulose or cotton based.
GB - Hot Pressed (H.P.)
F - Grain Satin
This indicates that the paper has acquired a smooth surface texture by treatment with heavy, heated rollers or plates. Think of a hot iron smoothing out all the folds. This paper has the characteristic that there is little or no grain in the surface and that you can work in great detail. The paint penetrates more difficult into the paper, making it easier to correct and to dab off the wet paint. Some prefer satin cellulose paper. This paper is also very suitable for refining your watercolour with ink.
GB - Cold Pressed/Not Hot Pressed (C.P./Not)
F - Grain Fin.
This indicates that the paper has a slightly rough surface that is achieved by pressing the sheets between felts, which transfers the felt texture to the paper. This paper has a texture that is visible and with the 100% cotton varieties, it absorbs the paint faster. Elevator technique or dabbing the paint is almost impossible here, because the paper absorbs the water and paint faster, a hint of the colour always remains. When using this paper you can apply several layers on top of each other (of course after the first layer has dried completely) without your colours getting muddy. With this paper, it is more difficult to start using ink because you are left with a slightly grainy texture and the pen falters on these small bumps.
GB - Rough F -
This describes the rough surface texture of paper that has been air dried without processing or by a felt with a coarse structure. This texture causes the paint to penetrate deeper into the paper, and it is sometimes difficult to predict what the paint will do. Lifting vases is almost impossible here precisely because the paint penetrates deep into the structure of the paper. Some skill is certainly required here. This paper is very popular with landscape painters and people who like to make abstract works. Of course, it is virtually impossible to work with fine details and if you want to work with ink pens, it is quite a job to bring this to a successful conclusion. Of course, the structures of the various brands are never the same and are a speciality of the producer.
Often this paper is labelled as inferior or only to be used as study paper. This is not quite right, cellulose is of vegetable origin and is not the same as years ago, formerly cellulose paper tended to discolour due to the presence of the Lignin, this substance causes a brown discolouration. This had to be fought with many chemicals and the paper was also treated with chlorine. This had a huge impact on the environment and now other less environmentally damaging techniques are used. The better cellulose papers nowadays do not contain wood pulp, and they also do not use optical bleaches and acids. So it is always good to look at what kind of paper you are buying. Of course, the selling price is already an indication of the quality. Many manufacturers now use the term vegan to show that their paper has been produced in an environmentally conscious manner. The fact is that an enormous amount of energy and water is used in the development of paper. Most quality brands now use these natural resources much more consciously than they did years ago. Of course, glues are used to hold the paper together, otherwise it would pulverize, but the use of these glues by many paper manufacturers is a well-kept secret.
Cotton Paper : This is, according to many, the ultimate paper. In the past, this type of paper was made from rags, but due to the many synthetic fibres found in the rags, they were forced to abandon this production method. The presence of synthetic particles caused transparent stains in the paper on which the paint did not stick at all. Nowadays, cotton linters (a residual product from the manufacture of yarns) are used, which have the advantage of being strong and able to absorb a lot of water. This paper has the property of discolouring less, and can stand the test of time very well. Of course, binders are also added. Sometimes a gelatin layer is applied to the paper that can vary in thickness. This aid can greatly influence the effect of the paint. Here too there are different qualities and price ranges but, as with cellulose paper, the selling price is an indicator of the quality.
To work well with watercolour paper, it is recommended that you stretch your paper so that it does not bulge while you are working. This is especially true if you like to work wet in wet. A somewhat cumbersome job but once you have mastered it, it is so pleasant to work with. Blocks that are glued on four sides are sometimes sold with the sales pitch that this will get rid of the clamping of the paper. I have already experienced that this is not always the case and that the paper sometimes shows its irregular edges.
Stretching watercolour paper When making a watercolour it is advisable to stretch your paper, especially if you are going to work wet in wet it is a necessity, otherwise your paper will bulge and the end result of your watercolour will not be beautiful. I stretch paper on a waterproof MDF board at least 1 cm thick. This board may not be varnished or painted otherwise the paper tape will not adhere to the board.
To stretch the paper, I place the paper in a bowl of water. Leave the paper there for a while so that it can absorb a lot of water. Then I place the paper between a towel and when most of the moisture is off I stretch it onto the board with brown or white paper tape. The slower the paper dries (always lay it down flat when drying!) the less the paper works during painting. If you do not have a drip tray at your disposal, wet the paper with a sponge and let it soak for a while. Wet it well and do not rub it. You will quickly destroy the structure of the paper. You can also wet it in the shower or bath, hold it at an angle so that the excess water can drip off and then stretch it.