How is this being printed? If it's going on press you should be sending it as a 1-up in single pages for the printer to impose to fit his equipment -- that's part of his job. If it's digital, and your sending it out, same thing, really, but I'd go along if they ask you to impose. Many commercial copiers that would be used for this sort of output have the capability to print 2-up or some other multiple built in to the RIP.
Many thanks for the replies.
Unfortunately the reason we're **** this is because we have a client who produces A5 Booklets.... but has no A5 Printer, so everything is printed A4, and cut down the middle. I don't know the full ins and outs to be honest.
We did however, work out a way to do this which I thought I'd post below, should it be of help to others in future.
1. We go File > Print Booklet in InDesign when we have our A5 pamphlet on screen.
2. We create a new print preset to print to Postscript inside this dialogue box.
3. We change booklet type to 2-up Consecutive.
4. In the range of pages to print, we type 1,1,2,2,3,3,4,4 and so on for as many pages as we have in the booklet as unfortunately, printing "All" simply prints it as it is on A4 paper. By typing 1,1,2,2, etc, it prints the same page alongside one another, which we want.
5. We press print, which exports the file a Postscript file (*.ps).
6. We open Adobe Distiller and change Default setting to "PDF A/1-b" (Obviously might differ depending on what you're printing)
6. We go to "Settings > Edit Adobe PDF Settings".
7. We change the Default page size to 297 x 210mm.
8. We drag the *.ps file into the white area and it converts it to how we want.
You could simplify this a heck of a lot doing what Eugene suggested with the addition of Scott Zanelli's marvellous script here.
1. Go File > Print booklet and print to PDF
2. Make a new A4 document in Indesign and run the above script twice.
3. Export that to PDF.
I would have imposed it in InDesign with Print Ready PDFs.
If you can't do the impo in your head then the Print Booklet - print it out and sit down with it in InDesign and lay it out exactly as you see it.
Then make the PDF from that.
The Print to Postscript and Distilling is very old school and problematic in it's own rights given certain circumstances.