Different papers are used for different processes. Cheaper papers have acid used in manufacture and this is to be avoided or the work will not last well. Good papers are ‘acid free’. Drawing paper is thin and is either white or available in several colors. Cartridge paper is cheap, but will not be acid free unless marked as such. Ingres paper is usually excellent quality, but is too thin for using with wet media. Watercolor paper is thicker, and often pure cotton, and so expensive. On the other hand it can take getting wet with a minimum of buckling and is usually worth the extra money. All papers made of pure rag or cotton are acid free, as acids are not needed in their manufacture