3.3. F3 SEQUENCE OF SIGNATURES/SHEETS panel

3.3. F3 SEQUENCE OF SIGNATURES/SHEETS panel

The F3 SEQUENCE OF SIGNATURES/SHEETS panel defines the program behavior when the imposed file has so many pages that one of the signatures will consist of a different number of pages than the declared complete signature (the so-called incomplete signature).

The order of signatures in a sewn binding is regulated by the rule that if a book block contains an uncompleted signature, then this signature is the penultimate signature of the book block. In other words, the book block consists of a certain number of complete signature sets nC (n denotes the number of complete signature sets) + an incomplete signature (U) + a complete signature (C), which is the last one. Each of these phrases may not occur, but at least one of them must occur.

This topic is best discussed using examples.

Example 1

Let's assume that we have a PDF file consisting of 160 pages for imposition (we can simulate this by entering this value in the F1 IMPOSITION FILES panel, without actually loading the file). We set the imposition parameters (number of pages in a complete signature: 32, number of pages per sheet: 8).

A table with 5 columns should appear under the PDF viewer (each column represents a signature, and the number of signatures for 160 pages is 5, which is calculated as 160/32=5), and 4 rows in each column (corresponding to the number of sheets needed to print one signature: 32/8 = 4).

The header of each column (signature) has the form, such as 2C • 32 • 33-64 • W4:S0:T4, which means:

• 2C – second signature Complete (it is also possible to use, for example, 2I to indicate Incomplete);
• 32 – number of pages in the signature;
• 33-64 – lowest and highest page numbers of the document placed in the signature. In the next signature, the lowest page number should be 1 higher than the highest page number in the previous signature;
• W4:S0:T4 – number of Whole sheets in the signature (4), Split sheets in the signature (0), Total sheets in the signature (4).

The description in individual cells of the table, i.e. sheets (e.g. 3 • W1x8 • 37:40 | 57:60 • 6) means:

• 3 – sheet number in the signature;
• W1x8 – sheet type, here Whole 1x8;
• 37:40 | 57:60 – pages of the document per sheet (each signature is a booklet, i.e. the sheets in a signature always have pages that are the same distance from the cover, i.e. the first sheet in the signature);
• 6 – consecutive number of the sheet from the set of all sheets.

For a 160-page book and a 32-page signature, the actual signature sequence is: 4C+0+C, i.e. 5C.

In the F3 SEQUENCE OF SIGNATURES/SHEETS IN SEWN BINDING panel, this status is described above the exception table as (5*32).

Example 2

Let's assume that we have a PDF file with 176 pages for imposition, which is 16 more than in example 1. After entering this value as the simulated number of pages for imposition, the number of columns increases by one. The number of pages in the added signature is the remainder of dividing the number of pages for imposition by the number of pages in the signature, i.e. 176/32 = 5 with a remainder of 16 (the number of pages in the Incomplete signature is 16).

According to the pattern for the sequence of signatures in a block (nC+I+C), the default sequence is: 4C+16+C, i.e. (4*32)+16+(1*32) – and this is shown in the F3 SEQUENCE OF SIGNATURES/SHEETS IN SEWN BINDING panel.

The user can perform operations on components and change their order using the context menu, which is called by right-clicking on the selected table cell. The menu is divided into two submenus: one with commands related to the signature [1], and the other with commands related to the sheet [2].

With these commands, you can plan any combination of signatures and sheets within signatures.

After changing the position of an incomplete signature, e.g. to the first one (commands: Signature > Move to beginning of book block and Signature > Move one signature to the right), the actual order of signatures is: (1*32)+16+(4*32).

If the actual sequence of signatures differs from the default sequence resulting from the general signature sequence formula, this is indicated in the F3 SEQUENCE OF SIGNATURES/SHEETS panel with red text showing the actual sequence of signatures

Example 3

Let's restore the default signature order by temporarily changing the number of pages to 180 and run the simulation again for 176.

When binding books with rounded spines, for example, instead of leaving an incomplete signature that is clearly off-center, it is recommended to divide the signature into two smaller parts and place each of them at an equal distance from the covers. Therefore, divide the signature into two smaller ones using the Signature > Split signature into two signatures command.

Using the menu commands (commands: Signature > Move to beginning of book block and Signature > Move one signature to the right), move signature no. 5 so that it is behind the first signature. As a result of this offset, the actual order of the signatures will be as follows: C+8+nC+8+C, i.e. (1*32)+8+(3*32)+8+(1*32), which was the intended goal.

Example 4

Let's assume that we have a PDF file with 164 pages to be imposed, which is 4 more than in example 1. As expected, the number of pages in the incomplete signature is 4 (which is the remainder after dividing 164 by 32). Therefore, the incomplete signature consists of only one 4-page signature, and the current signature order is now nC+4+C, i.e (4*32)+4+(1*32).

However, sometimes for technical reasons, sewing only one sheet is either difficult or impossible. A situation where a book block contains a signature consisting of only one sheet is undesirable.

Select any sheet in signature no. 4 and use the context menu command Sheet > Move sheet to next signature to move the selected sheet to signature no. 5 (incomplete). As a result, signature no. 4, which was complete until now, has become an incomplete signature (containing 3 sheets, i.e. one less than in a complete signature). The number of sheets in signature no. 5 is now 2. As a result, we now have two incomplete signatures in the book. The actual order of signatures in the block is 3C+24+12+C, i.e. (3*32)+24+12+(1*32).

There is also another method for removing a signature consisting of only one 4-page signature by merging it, for example, with the previous signature. To do this, use the Signature > Merge signature no. 5 with previous signature command, creating a signature with more pages (36) than the number of pages in the complete signature (in this example, the complete signature has 32 pages):

The color of the incomplete signature column header can be changed using the command from the context menu Incomplete signature header color.