http://www.articlesbase.com/k-12-education-articles/what-is-a-blackline-master-1380248.html A Blackline master is a resource book usually bought by schools for their students to use. It can be about any topic from math to reading; poetry to comprehension. If the school were to purchase a book for each of its students, the cost would be astronomical. Photocopying is the answer. But to buy one book and make many copies of the pages is actually a breach of copyright. The author of the book could sue schools for doing this. But there are books written especially with photocopying in mind and these are called Blackline masters. These books have a certain number of pages that it is legal to photocopy many times. Simply by making photocopies of the relevant page, the teacher can now provide worksheets for students at a reasonable cost. The school only need buy one book per class, bringing their costs down significantly. In fact the book can be used over and over for a number of years and classes, becoming a great resource for very little outlay. A Blackline master will also have certain pages containing notes to help the teachers. This could suggest other activities that will help he children understand their lesson, or it could simply be advice to the teacher about what would be helpful for them to teach the lesson.

If the worksheets were provided simply as sheets instead of in book form the masters could easily get lost. Teachers would have to provide some kind of folder to store them in. Then the order of the sheets could be mixed up and those sheets that were not meant for photocopying would be mixed up with the others. When a book form is used, all the pages can be kept in a readily identified format that is easy for the teacher to use.

And all the students are provided with a page of their own to work on. If they make a mistake, another page can be provided for next to no cost.

The pages for photocopying in a Blackline masters book are often those without very much text on them. This is because there must be room left on the pages for answers to be written. Teachers who have a good understanding of what is needed in the classroom situation are usually the authors of Blackline masters. Thus the school knows it is getting quality material that will enable teachers to teach their students in an appropriate manner.