When you print a perfect bound book on offset it is folded into 4, 8, ,12, 16 or sometimes 32pp sections, during the folding, the signatures are notched to allow the glue to penetrate, this is called notch binding.
A digitally printed perfect bound book is, as you say, a bunch of sheets glued together.
It is possible to print the job offset, cut down to single leaves, collate and insert the colour pages where required, however, due to the additional finishing cost, it would probably be cheaper to print the whole job offset.
To keep costs down, ask the printer for an imposition, mark the colour pages on the imposition, if the colour pages can be moved, try to minimise the number of colour formes.
Alternatively, you can place the colour pages in between offset sections, this obviously limits where you can place colour pages and will reduce the overall integrity of the binding due to the colour pages not being notched.
In this case, if the colour pages were mid-section (eg. page 9 & 10 in colour) we would print as part of the offset section. if the colour pages fell between sections (eg. pages 17 & 18 in colour) we would consider doing as a loose page insert, especially if it was on a different stock.
@Magnus59, the problem is that dilletantes like me see the book as "a bunch of single
(individual) leaves", which in most cases is not true. Thank you for clearing that up for me.
So the printer who rejected my idea is not incompetent, its just you can't insert whatever you want anywhere you want. At least not in this case. Prepress designers should be aware of this from the very start.
The folding / binding method that this printer uses means folding the sheet in a complex way that will produce
groups of pages.
In order to have a bunch of single leaves, in which you can insert something, the printer will have to ungroup the pages, i.e. to cut the sheets in a certain way, which might be complicated and expensive.
That's how I understand you (to put it simply).
Basically, the folding process is similar to the pic below:
Another printer told me that he can assemble this offset/digital combo for me. But note that he uses smaller sheets, which (I suppose) gives him more freedom.
But his printery is quite modest and his test-prints did not turn out so well (which is another problem), so I decided to go somewhere else.
I think we need more information.
@gordo has the right idea in that you should tell the printer what you want your books to look like and let them decide how to produce it. They made decide to do the whole thing digitally or offset depending on the quantity. There could be many reasons for them telling you no. It could be the signature issue
@Magnus59 mentioned. It could be because the digital full color prints will be on a coated stock, while your b/w offset sheets are on an uncoated. If they are doing EVA glue, it will not hold coated sheets, you would need PUR glue. If they will be printing the b/w pages, but you're getting the color sheets elsewhere and bringing to them, that could cause a big disruption into their workflow to get that sheet collated into the rest of the book. Just send the whole file to one printer and let them produce it as they see fit for their methods. If you don't like their pricing to do that, get other bids.
Thanks for the explanations,
@jwheeler
Judging by what the printer told me, this has to do with the signatures.
I would like the book to be a combination of offset and digital for aesthetic, creative and technical reasons. Is this feasable or not is another problem. I don't want to let the printer decide for me, unless there's no other way.
I would like the color pages to be printed digitally on an uncoated stock. This usually gives me a print that has a shiny surface and vivid colors, but on a paper that looks 'natural'. This would fit well with the rest of the book.
There are different digital printers (laser, ink-jet), different manufacturers and settings, and I'm not an expert on all that, but that's what I generally get when I print test pages.
Another reason for using digital is that I have to deal with printers who cannot get the colors right in offset (which I explained in
another post). Digital would be a better solution for this.
Offset looks "dry" on uncoated stock, cause the ink will be absorbed into the fibres, so if you print colors that way, they might look dull. But this will work fine for the grayscale content, at least for my taste.
That's the reason why I want such "analog / digital" mix.
Other solutions:
I've read online (I don't know how credible this is) that "tipped-in pages are generally glued to a bound page on its inner side". But I'm afraid that the inserted leaf might not be glued well enough and it may fall off (as I mentioned before, some people warned me about this).
I also heard that there are digital printers (I guess ink-jets) that can emulate offset, but to what extent - I don't know. Maybe this could be a solution.
