Mohamed  Hirji

Fine Art

A Curious Pair

Apr 5, 2019

For purposes of paintings, a substrate is the surface on which the paint is applied it is also called painting support. There are unique substrates suitable for different media. For this blog, I am going to confine myself to discussing the substrates used for watercolors.


One of the most important prerequisite for any substrate is that it must be acid free and therefore archival. As we see in newsprints or ordinary papers, acids within the cellulose fibres which make up the papers, degrades the paper (substrate) over time, making it yellow and brittle. We do not want that to happen to our valuable paintings.


Traditionally watercolours are painted on "paper" the cheaper of these papers may be made up of buffered wood pulp, (cellulose). A good clue is that these papers do not indicate the (ingrediants) make up of the paper on the package.


This is an example of a substandard 140 lbs paper: Caution - even though it indicates acid free, it is not archival

This on the other hand is an example of a good quality paper. 100% cotton, 140 lbs paper. This is clearly indicated.

Quality: The highest quality watercolor paper is actually a fabric which is 100% acid free cotton. During the process of painting, the watercolour paint "dyes" the fabric to varying degrees these papers will clearly indicate what they are made of and often have a watermark identifying the make of the paper.

Watermark On A Top Brand Arches Paper

Size: Watercolour papers are either sold in small pads, of several sheets called blocksor pads. These blocks are made of several small sheets of watercolour paper which are  glued bound at the edges to minimize buckling when wet. These carry a premium price.


The watercolour paper may also be purchased as individual sheets measuring 22inX30in (a full sheet) which can be cut to any desired size. Since watercolours are traditionally framed behind archival mat and glass, any framed watercolour painting larger than a full sheet would become too heavy and therefore it is rare to find watercolour paintings larger than 22inX30in

Weight : The "papers" also come in different thickness (weights) common ones being 90lbs, 140lbs (300gm/m2) and 300lbs (640gm/m2). These numbers are derived from how much a ream (500 sheets) of 22inX30in would weigh. The lighter the papers, the more tendency it has to buckle when wet. Therefore The 90lbs paper is almost exclusively used for rough sketches and small studies. The 300lbs paper is thick like a card and is ideal for painting but it is much more expensive so most individuals use 140lbs which can be stretched to prevent buckling during wet washes. The paper weight is usually indicated on the package.

A 90lbs Watercolour Pad. This is  NOT  A 100% Cotton Paper:

A 140lbs watercolour paper, although it contains cotton, beware, unless specified it is unlikely to be 100% cotton paper and may even contain  less than 10% cotton.

Texture: The Arches papers  comes in 3 different textures, namely Hot pressed which is very smooth, mainly used for portraits, Cold pressed which is a bit rough and Rough which is highly textured. The rough texture is ideal for dry brushing techniques. Cold Pressed paper is used most commonly.

The Smooth Texture Of Hot Pressed Paper

The Semi-Smooth Texture Of Cold Pressed Paper

The Coarse Texture Of Rough Paper

Lately, some compounds have been developed which can be applied over other materials like birch boards or canvas to allow watercolours to be painted on these products, also readymade watercolour canvases are now available. Since these would not be framed behind glass, the paintings need to be protected by special varnishes.

If you enjoy this blog/newsletter, please forward it to your friends and contacts. You may also wish to subscribe to my newsletter in which case this will be delivered to your email.

Thank you for following.



Mohamed Hirji