Why You Shouldn’t Use a Basic Pencil Sharpener on Sketching Pencils
When you’re using sketching pencils you want them to have super fine tips to allow for drawing intricate details and fine lines. You’re not going to get a super fine point if you’re using a standard pencil sharpener. In fact, you will likely break the lead in the pencil before even coming close to the fine tip you’re trying to get. This is why a basic pencil sharpener will not work for sharpening sketching pencils.
You either need to purchase a pencil sharpener designed for use with sketching pencils or you can sharpen them by hand using a straight razor blade.
If you go with this latter method, you need to be sure the razor blade is extremely sharp, and you need to wear protective gloves to avoid injuring yourself. Use the razor blade to carve a long, sharp point on the lead of the sketching pencils for the best results.