Students Guide : Calculating the Paper requirement

(Written by : N.R. Jayaraman)

One of the printing students sought my guidance on how to calculate the requirement of paper for printing the books. Therefore with a view to guide the students in general a model illustrative workout has been given below.

Several factors are involved in calculating the requirement of paper for the production of a book. The cover material, and bindery, printing process etc involving the production of a book has been omitted in this article and only the direct requirement of paper has been dealt. The sizes and other technical aspects indicated in this article are purely imaginary and are meant to only explain the concept and to guide the students.

The critical points to be considered while calculating the requirement of paper for the production of a book is:

The size of book to be printed
Main text- Overall size
Margins required on all sides of the main text material
illustrations
Side stitch or saddle stitch (This is important because the overall size of paper required partially depend on it)
Max size of paper printable on the machine in hand.

The books to be printed are normally confined to standard size because of the standardization of the paper, as odd size of finished book results in wastage of paper. The paper in reams are available in different sizes such as A series, B and C series besides Demy, Double demy, Crown, Double crown,

A) Requirement (Model):

Let us assume the specification of the book to be produced has following specification shown below:

Book size A5 : 148 mm x 210 mm which is ‘I’ and ‘II’
Dimensions of matter per page 128 x 190 cm which is ‘III and 'a'
Margin required around the text 10 mm on all sides ‘b’, ‘c’, ‘d’ and ‘e’ per page
No of copies to be printed : 500
Machine capacity : A3 size printable at a time
Total no of pages guesstimated :410**

{** based on the complete typed material or manuscript with a variation of plus /minus 2 %. Read the model calculation given below}

B) Model (Ready reckoner):

Let us assume that the manuscript typed or handwritten has 100 pages, each page having approximately 1000 words in the manuscript and the same has to be printed in the specification stated above. Calculate from the manuscript no of pages which may be required to be printed in 10 pt Times Roman font.

Generally the expert printers keep sample workouts to approximately calculate no of pages instantly. The sample workout kept by them is based on no of words per 5 cm x 10 cm square (50 square cm) which will normally be:

10 pt Times Roman type face with single line space say 100 words
10 pt Times Roman type face with 1½ line space say 75-80 words

Therefore average words per 50 square CM in 10 point font can be say 90 words. Similarly in 12 point font it will be :

12 pt Times Roman type face with single line space say 80 words
12 pt Times Roman type face with 1½ line space say 70 words

Therefore average words per 50 square CM in 12 point font can be say 75 words.

Normally an A5 size paper can accommodate say 30-32 lines in each page. Then the total no of words on A5 (12.8 cm x 19.0 cm = 243.20 sq cm) sheet with 10 point font will be:

243.2 sq cm ÷ 50 sq.cm x 90 words = 288 words rounded to 290 words or rounded to 250 words on an average taking into consideration space for intermediary headings, page no, title etc.

C) Work out from manuscript to printable pages:

Based on above calculate no of pages the manuscript will work out.

Total no of words the manuscript has : approximately 1000 words per page x 100 pages = 100000 words
Per A5 size paper no of words composable : 250 words
No of pages in which the contents of manuscript can be accommodated will work out to :- 100000 ÷ 250 words = say 400 pages + title page +Half title page + illustrations (5 pages) + end papers for binding (10 pages ) = 410 pages approximately.

This is how the printer normally work out the gustimates and the next step is calculating the requirement of paper for above.

D) Work out for requirement of paper from guesstimated pages :

Next you have to decide the machine capacity for printing like the maximum size paper printable and then whether the printing will be done on normal printing machine or by Digital printing. This is important because on normal printing machines, some blank margin may be required for the grippers to keep the paper in position during printing. Therefore while working out the size of paper due allowance for gripper margin- minimum 10 mm is taken in addition to the finished size of the book for feeding on to the machine. In Digital printing however such problems does not arise. Also some small allowance is kept for final trimming of the edges of the book to size. Say 5 mm allowance is added on each side of the paper for final trimming.
If your machine capacity is to print only A4 size paper, then four pages (2 + 2) of A5 size (which is the size of the book required) can be accommodated on both sides. However if your machine can take A3 size paper then 8 pages can be printed on both sides (4 + 4).

Four pages printing of A5 size : -

What will be the layout position for printing 2 or 4 pages in a sheet?
When you print two pages per sheet the layout would be something as shown below. The trimmed size of normal A4 size paper is 210 mm x 297 mm. It can though accommodate two pages of A5 size, unless the surrounding blank margin around the text is sufficient enough to feed on the machines which needs some space to grip the sheets beyond which only the matter can be printed, due allowance may be needed if it is printed on the machine.

Similarly some extra margin may be required to trim the printed sheets after they are compiled into a book and bound. Therefore due allowance for trimming too may be needed. With cutting and gripper margin the size of paper required will work out as below:-

210 mm + 10 mm gripper margin + 10 mm as cutting allowance = 230 mm on one side.
148 mm +148 mm + 10 mm cutting allowance for both sides + 5 mm in centre other than the final margin on finished book = 312 mm on second side.

Thus the final requirement of paper works out to 230 mm X 312 mm for printing two pages at a time.

Four pages printing of A5 size : -

When you print as four pages per sheet the layout for the same will be something like the four pages as shown below. The paper size will be 420 mm x 297 mm without allowance for cutting. With cutting and gripper margin the size of paper required will work out as below:-

297 mm + 10 mm gripper margin + 10 mm as cutting allowance + 5 mm in centre other than the final margin on finished book = 322 mm on one side.
210 mm +210 mm + 10 mm cutting allowance on both edges + 5 mm in centre other than the final margin on finished book = 435 mm on second side.

Thus the final requirement of paper works out to 322 mm X 435 mm for printing four pages at a time.

E) Now the work out of paper requirement to print 260 pages x 500 copies:

Ref 'Para A' in which the no of pages have been guesstimated to be 410 and no of copies required is 500.

Generally 2 % allowance is added as wastage for printing related problems of many nature. So the actual no of sheets required to print 410 pages book of 500 copies will be :

Two pages printing of A5 size : -

410 pages ÷ 2 pages printing per sheet (205) ÷ two sides (102.5) x 500 copies + 2% = 102.5 x 500= 51250 + 1025 = 52275 sheets of 220 x 312 or 230 x 312 mm size paper equivalent to 105 reams (rounded)

Four pages printing of A5 size : -

410 pages ÷ 4 pages printing per sheet (102.5) ÷ two sides (51.25) x 500 copies + 2% = 51.25 x 500 = 25625 + 512.5 = 26137.5 sheets of 322 mm x 435 mm size paper equivalent to 53 reams (rounded).

F) Now the work out of paper required to be procured from the market to print 410 pages x 500 copies :

The sizes in which the paper is available in the market is important for this calculation. As said earlier there are several sizes of paper available in the market as supplied in the sizes ranging from A, B and C series. Paper is also available in the sizes like Demy, Crown, Double Demy, Double crown etc.
Therefore find out the best size of paper available in the market to get sheets cut to the actual requirement as worked out above without causing much wastage. In this model case paper equivalent to A4 and A3 in B series will be required. See circle above.

==================================

NOTE **The above sizes shown are purely imaginary for explaining the calculation. They are not accurate in sizes. Therefore you have to calculate your working on the lines shown above.