Rough, Medium (Cold Pressed) and Smooth (Hot Pressed) Watercolor Paper
The best quality watercolor paper is acid free and made from 100% cotton fibre. These papers are usually buffered with calcium carbonate to keep the pH level slightly alkaline. They can be hand made or mold made, but generally not machine made.
Lower quality and student grade watercolor papers are usually machine made and derive their cellulose content from wood pulp or a mixture of wood pulp and cotton or linen fibres.
Watercolor Paper Texture
Watercolor paper falls into three basic textures – Rough, Cold Pressed, sometimes called“ Not” (medium Texture) and Hot Pressed (Smooth Texture).
There is no standard for texture so what one manufacturer calls rough may be similar to another manufacturers Cold Pressed.
Rough paper allows for maximum pigment granulation, but the paper appears slightly darker than smoother papers due to the shadows cast by the surface texture. It is more suited to a broad, loose approach and not good for fine detail. Rough paper accepts big wet washes well and doesn’t bloom (create those cauliflower shaped blotches) like Hot Pressed paper tends to.
Hot pressed paper is great for intricate detail and, because of the flat surface, gives more brilliance to colors. Big flat, even washes are more difficult to achieve on Hot Pressed paper as it usually has more surface sizing than the heavier textured papers.
Cold Pressed paper doesn’t have the texture of Rough, so doesn’t granulate as much, but is better for detail while still having a little texture.
Watercolor Paper Weight
As well as the variation in texture there is a variation in watercolor paper weight.
Most manufactures make their papers in a number of different weights from thin, light weight papers suitable for sketching up to heavy cardboard like papers that require no stretching or preparation before painting.
In the USA paper weight is designated in pounds.
140lb paper means a ream (500 sheets) of that paper weighs 140lb.
In Europe paper is classified according to its weight in grams per square meter.
The most popular paper size is the Imperial Full Sheet which measures 22×30 inches or 55x76cms. These dimensions can vary slightly between manufactures due to variations in the rate of shrinkage as the paper dries. Full sheets can be cut into smaller standard sizes – 1/2 sheets (15×22 inches or 38×55 cms) and 1/4 sheets (11×15 inches or 27.5x38cms)
The most common weights for Full Sheets are:
90lb or 185gsm – Good for sketching, too thin for painting
140lb or 300gsm – Good for painting, most popular weight
280lb or 600gsm – Good for painting, needs no stretching, expensive
Larger sheets such as the“ Double Elephant” 29x41inches or 74x104cms are available as are rolls of paper up to 10 meters long and 1.2 meters high. Most manufactures offer their most popular papers in sketch books and blocks of various sizes.
Keeping paper sealed in plastic storage bags helps protect against mould and mildew in humid environments.
There are many brands of watercolor paper available and all offer a similar selection of weight and texture. My favourite paper is the Arches 300gram Cold press. It is robust and forgiving with just the right amount of sizing.
Manufacturers add sizing to the paper pulp mixture to control the final absorbency of the paper. They also externally size the paper after it has been moulded. Watercolor paper with too much external sizing makes it difficult to produce a large, even wash. Too little sizing and the paper can act like blotting paper. Anyone that has mistakenly tried painting on print making paper will have experienced this problem.
Which Watercolor Paper is Best?
Faced with all these options in weight texture and quality, the choice is not easy, but there are a few things that can simplify making a decision.
If you intend to sell your work choose an Acid Free 100% Cotton Paper with a weight of at least 140lb or 300gsm.
Paintings under a 1/4 sheet size can be done on paper lighter than 140lb (300gsm) but from 1/4 sheet up light weight paper is unsuitable.
Full sheet paintings using large, wet washes will need stretching to guarantee smooth washes. If you don’t want to go to the trouble of stretching the paper, choose a heavy 280lb (600gsm) paper.
The choice of manufacturer is a personal one and can only be decided by experimenting. The sizing and texture of watercolor papers vary from one maker to the next. It is a good idea to buy a couple of sheets, cut them into quarters and do a number of small paintings before making a decision. It always takes a few paintings to become accustom to a new paper, so don’t write off a paper on the strength of just one painting.
Watercolor Paper – Sheet, Pad, Block or Roll
Most watercolor paper is sold in standard single sheets which are around 22×30 inches (56×76 cm). These are great in the studio but cumbersome when painting outdoors.
Blocks are good when painting on location as the paper stays flat then, once the painting is finished, can be removed by inserting a credit card or blunt knife in the opening at the top and running it around the page. Pads are also good on location as all your work stays together.
A credit card slipped into the opening at the top of a watercolor block and run around the edge is the safest way to remove your finished painting.
Roll paper allows you to work on larger sheets. The rolls are around 4 feet by 30 feet long and are an economical way of buying watercolor paper.
Stretching Watercolor Paper
Stretching paper makes flat, even washes easier to apply and, after the painting is finished, produces a flat unbuckled art work. The traditional method of stretching watercolor paper is to soak it in a tub of water for twenty minutes then, while wet, stretch and pin it to a light, braced ply backing board. Once dry, the paper shrinks to a tight flat surface.
I stretch Arches paper by spraying the back of the sheet with water, letting it soak in for a few minutes then taping it, face (dry) side up, to a backing board with gummed paper tape.
The paper is allowed to dry and shrink to a tight, flat surface. The sizing on wet Arches paper reacts with the gum paper tape, but spraying just one side overcomes the problem.
After the painting is finished it is cut off with a craft knife and the remaining gummed paper is soaked with a wet brush and peeled away.
Flattening Watercolor Paper
Since using a dry hake brush to even out watercolor washes, I have found stretching unnecessary. I now work on loose, un-stretched paper then flatten the finished work in the following manner.
Spray the back of the painting with water
Lay it on a flat table covered with absorbent cloth
Cover the work with another layer of absorbent cloth (keep the cloth free of wrinkles)
Place a flat sheet of heavy (20mm) ply on top
Put a heavy weight on top of the ply (old car battery or 20litre drum of water)
Leave the work for a couple of days to dry out. The result is a perfectly flat sheet of paper. This procedure takes a couple of days, but the results are always good.
Cold Pressed Watercolor paper is the middle ground paper – not too rough and not completely smooth. It is good for most subjects and techniques.
Hot Pressed Watercolor Paper paper is great for fine detail where big at washes are not required. The surface sizing on most Hot Pressed paper means pigment can be easily lifted off. Colors on Hot Pressed Paper are more vibrant due to the lack of texture.
Rough Watercolor Paper has a heavy texture and is suitable for fractured, textured subjects without too much fine detail.
It is possible to take advantage of the strong, vibrant colors and fine detail available with Hot Pressed Watercolor Paper then, with a vigorous application of watercolor Gesso, build up heavy texture where required.
Author: John Lovett