Prepress production is everything that happens after you send files to a printer and before ink hits paper. It’s part technical, part quality control, part “we’ve seen this mistake 10,000 times and we’d prefer not to print it again.”
A competent prepress tech is looking for anything that could cause production errors: missing bleed, incorrect trim size, low resolution images, font issues, broken transparency, accidental spot colors, bad overprint settings, or that one page that exported sideways for no clear reason.
And yes, software helps. But software does not understand what you meant. Humans are still required.
Step one: File review and preflight (manual + software)
Most serious printers run some combination of:
- Manual review by an experienced technician
- Preflight software checks to flag common problems
Preflight tools can catch objective issues (bleed missing, RGB images, fonts not embedded, image resolution too low). The human catches the practical issues (your fold line is off, that “safe area” is a lie, the dieline is on the wrong layer, or the barcode is sitting in the trim).
If your PDFs pass inspection, you typically get an electronic proof.
Proofs: your last cheap chance to fix things
In prepress production, proofing is where the printer asks: “Is this what you want us to make?”
Electronic proofs (soft proofs)
An electronic proof is usually a PDF proof that shows:
- Your final layout
- Page order (when applicable)
- Printer’s marks added by the printer
- Sometimes notes from prepress about recommended changes
This is often free and often mandatory, because it prevents disasters that are wildly avoidable.
Hard copy proofs (when color really matters)
For color-sensitive projects like books, board games, packaging, or anything where “close enough” is not acceptable, a hard copy proof may be offered. It’s typically requested when:
- Color matching is critical
- You have large solid areas (especially darks)
- You need to validate a specific stock/coating look
Soft proofs are great for layout and content. They’re not reality. Paper and ink are reality.
What to check before you approve a proof
Proof approval is the moment where responsibility quietly transfers from “printer can save me” to “printer will print exactly what i approved.”
Here’s what to actually check:
- Trim + bleed: Do you have bleed, and is the important stuff inside the safe area?
- Text: Typos, missing lines, weird spacing, wrong phone number, outdated QR code. The classics.
- Images: Resolution looks acceptable, no pixelation, no accidental compression, no missing links.
- Color intent: If your blacks look muddy or your brand color looks off, flag it now.
- Pages: Correct page count, correct order, no missing pages, no duplicate pages.
- Special layers: Spot UV, foil, white ink, varnish masks, dielines: present, labeled correctly, and not accidentally visible.
If the prepress tech suggests a fix, read it. They are not trying to win an argument. They are trying to keep your job from becoming a cautionary tale.
Printer’s marks: the weird lines you didn’t design
When you get a proof back, you’ll usually notice extra marks around your artwork. These are printer’s marks, and they help the press operator and finishing team produce and cut the job correctly.
Common printer’s marks include:
- Crop marks: show where the piece trims
- Bleed indicators: show where bleed extends
- Center marks: help with alignment
- Registration marks: help align CMYK plates on press
- Color bars: help measure color consistency
- Fold marks: for folded pieces
- Slug area notes: job info, versioning, internal tracking
Important: these marks are usually outside the final trim and get cut off. They’re not “mistakes.” They’re the printer doing their job.
Imposition and pagination: why your pages get rearranged
Imposition is the process of arranging pages on a larger sheet so that, after printing, folding, trimming, and binding, everything ends up in the correct order.
This is where printing stops being “pages” and becomes “signatures,” “forms,” and “press sheets.”
Why it matters
If you’re printing anything multi-page (booklets, books, game rulebooks, catalogs), the printer may:
- Split pages into signatures
- Adjust for creep (page push-out in saddle-stitched booklets)
- Align gutters for binding
- Ensure pagination survives folding and trimming
Even for non-book jobs, imposition matters. Think sticker sheets, card sheets, or anything “step-and-repeat.” Your art may be duplicated, nested, and spaced to optimize production and finishing.
So yes, the printer might send you a proof where pages look “out of order.” That can be normal. What matters is that the final folded/bound piece reads correctly.
After approval: RIP output and (sometimes) printing plates
Once you approve the proof and the job goes to press, the next big step in prepress production is typically the RIP.
What RIP does (in plain English)
RIP stands for Raster Image Processing. It converts your vector/text/image PDF into the exact pixel-by-pixel instructions the press needs.
In this stage:
- Your images are separated into CMYK (cyan, magenta, yellow, black)
- Output is generated for the printing process
Offset printing: plates are part of the deal
In traditional offset printing, RIP output is used to create four metal plates, one for each CMYK color. Those plates get mounted on cylinders on press. The press then combines the four inks to create the full-color image.
Plates are thin metal sheets, durable enough for long runs, and flexible enough to wrap onto press cylinders. If you’ve ever wondered why offset is so good at consistency on big runs, plates are part of the answer.
Digital printing: still RIP, usually no plates
Digital presses still use RIP processing to interpret your files, but typically do not require physical plates. The concept is the same: the printer needs precise instructions for how to place color, how to handle transparency, and how to reproduce the file reliably.
Either way, the RIP is where “looks fine on screen” meets “this is what we can actually print.”
The four prepress production chapters (the version you can remember)
If you want the short mental model, prepress production usually boils down to these buckets:
Proofs
The checkpoint. Confirm layout, content, page count, and anything special (foil, UV, dielines). Fix problems while it’s still cheap.
Printer’s marks
The map. Helps production cut, register, align, and finish the job accurately.
Imposition and pagination
The puzzle. Pages and pieces get rearranged to print efficiently and assemble correctly later.
Manufacturing printing plates
The “commit” step for offset. RIP creates separations and plates, and now the press is ready to make your job very real, very fast.
What to ask a printer before you order (if you want fewer surprises)
If you’re comparing print vendors, these questions tell you a lot:
- Do you run manual + automated preflight?
- Do you provide electronic proofs, and are they required?
- Will your proof include printer’s marks?
- For books/games, can you provide a hard copy proof for color?
- Who reviews flagged issues: a person, or a ticketing system?
A printer that treats prepress seriously is usually a printer that treats your outcome seriously.
Final thought: prepress is boring until it saves your job
Nobody wakes up excited to talk about printer’s marks. But prepress is where most print disasters are prevented, quietly, by someone who has seen your exact mistake a hundred times.
Treat proof approval like a real approval. Because it is.