What to use for urban sketching: a sketchbook or loose sheets of paper? What are the advantages of the one or the other?
Using a sketchbook instead of single sheets has advantages and disadvantages. With a sketchbook you do not have to deal with loose sheets on the go and you also create a visual document of a period in your life. A loose sheet you can just throw away. The disadvantage of a sketchbook can be that a sketch will be there forever, whether you are satisfied with it or not. Unless you would like to ruin your sketchbook by tearing out the sketch. However, personally I think that is an advantage of a sketchbook. Later you will be able to look back and learn from improvements that you see in previously made sketches.
I myself work in sketchbooks as well as on separate sheets. If I expect a sketch to be eligible for framing or for others to have, then I choose to work on a separate sheet.
Finding the paper that works for you is perhaps the hardest part when it comes to choosing materials. That becomes a lot easier if you know what to look out for. I like to take you into what I think is important about the paper, that I use, and what I have discovered and learned.
The quality of your paper
The quality of your paper is more important than the quality of your pen or paint. High quality paint will still not look very good on bad paper. When choosing a sketchbook or paper, I always make sure it is real watercolor paper, as I usually use watercolor paint for my colors. I prefer acid-free paper made of 100% cotton and a weight of 300 gsm (grams per m2). I am then assured that the paper can withstand a lot of water and that it will last for decades. Acid-free paper prevents your sketch from fading after a few years. Note that sketch paper is often less suitable for watercolor, as it assumes you are using a pen and / or pencil.
If you work with markers, it is wise to learn more about paper that is specially made for that medium, so that your marker colors do not “bleed”. I do not use markers that often, so I go for watercolor paper.
I hope this will help you looking for the perfect medium for your sketches. Experiment with samples of paper if you can get hold of them. That is the best way to find your favorite paper.