ISO 5350-1:2006规定了一种通过透射光估算纸浆制备的实验室纸中可见污垢和碎片的方法。原则上，它适用于所有类型的纸浆，尽管它主要用于非片状生产的纸浆。 ISO 5350-1:2006也适用于磨碎的片状纸浆，如果片状纸浆的重量较高或由于其他原因非常不透明，在这种情况下ISO 5350-2:2006不适用。 ISO 5350-1:2006不适用于回收纸浆。

ISO 5350-1:2006 specifies a method for the estimation by transmitted light of the visible dirt and shives in laboratory sheets prepared from pulp. It is, in principle, applicable to all kinds of pulp, although it is mainly intended for pulp that is not manufactured in sheet form. ISO 5350-1:2006 can also be applied to mill sheeted pulp, if the sheets have high grammage or are very opaque for other reasons, in which case ISO 5350-2:2006 is not applicable. ISO 5350-1:2006 is not intended for recycled pulp.