If a printer has emailed you asking for “the file with bleed”, they are not being difficult. They are telling you that the file you sent will come back with a white hairline down one edge, and they would rather say so now than after they have cut two hundred cards.
Print-ready is not a quality judgement about your design. It is a short list of technical conditions, and every one of them exists because of something physical that happens in a print shop. Once you know what the machine is doing, the vocabulary stops being intimidating.
Bleed exists because cutting is imprecise
Cards are not printed one at a time at their final size. They are printed several to a large sheet and then cut down with a guillotine or a die. That cut has a tolerance. It can drift by a fraction of a millimetre, and on a stack of card it drifts more at the bottom of the stack than at the top.
So if your background colour stops exactly at the edge of the card, any drift outward puts unprinted paper on the edge. That is the white hairline. The fix is to extend the background past the finished edge, so that when the blade wanders it is still cutting through colour.
The standard extension in the US is an eighth of an inch on every side, which is 3mm in metric shops. A 5 by 7 inch invitation therefore gets built at 5.25 by 7.25, with the outer eighth of an inch understood as sacrificial. It will be sliced off. That is the point of it.
Three terms describe the same card at three sizes:
- Bleed is the outer edge of the artboard, an eighth of an inch beyond the finished card.
- Trim is where the blade is aimed. It is the finished size, and on a proof it is marked with crop marks.
- Safe area is an inset from trim, usually another eighth of an inch, sometimes a quarter. Nothing you care about goes outside it.
Safe area is the one people skip, and it is the one that ruins otherwise good files. Drift can go inward as well as outward. Type set 2mm from the trim line will, on some cards in the stack, end up 0.5mm from the edge and look like a mistake.
Resolution is measured at the size it prints, not the size it was
An image is a fixed grid of pixels. Enlarging it does not add any. The number that matters is how many pixels land inside each printed inch, and for print the working figure is 300 pixels per inch at final size.
That gives you an easy piece of arithmetic. A photograph that will fill a 5 by 7 card with bleed needs to be at least 5.25 times 300 by 7.25 times 300, so roughly 1575 by 2175 pixels. Anything smaller gets soft, and the softness shows up first in fine detail like hair, foliage and small type inside the image.
Screen images are the usual trap here. A photo pulled from a website or a social app is often around 1000 pixels on its long edge, which is plenty for a phone and not enough for a card the size of your hand. It will look perfect while you are working and disappointing when it arrives.
Vector artwork is the exception. Type, line illustration and logos drawn as vectors have no pixel grid at all, so they print sharp at any size. That is why a good invitation file keeps type as live type rather than flattening it into an image.
CMYK and RGB are two different ways of making colour
Your screen makes colour by emitting light. It starts black and adds red, green and blue. Paper makes colour by absorbing light. It starts white and adds cyan, magenta, yellow and black ink, each of which subtracts part of the spectrum.
The two methods cannot reach the same set of colours. Screens win on anything luminous: electric blues, hot pinks, bright oranges, acid greens. Those sit outside what four inks can mix, so when the file is converted for press, the printer’s software substitutes the nearest achievable colour. Usually it looks slightly duller and slightly greyer than what you approved on screen.
This is not a failure. It is the physical limit of ink on paper, and it is why a printer asks for a CMYK file. Converting deliberately, at design time, means you get to see the substitution and adjust for it. Converting accidentally, at the press, means the machine chooses for you.
Two practical consequences worth knowing. First, deep blacks in print need more than 100% black ink; a rich black mixes in some cyan, magenta and yellow, and a large black panel built from black alone looks washed out and slightly brown. Second, if a colour has to match something physical, a swatch of fabric or a paint chip, tell your printer that at the quoting stage rather than after the proof.
Fonts, layers and the file you actually send
The safest thing to hand a print shop is a PDF, exported with the print preset, with fonts embedded and bleed included. Embedding means the letterforms travel inside the file, so it does not matter whether the printer owns your typeface. Without embedding, the shop’s software silently substitutes something else and your careful spacing collapses.
A PDF also flattens the argument about software versions. You do not want a print shop opening your working file, on a different machine, with a different version of the same program, and discovering that a drop shadow renders differently.
If you are sending files somewhere yourself, name them so a stranger can tell them apart at a glance. Something like surname-invitation-5x7-print.pdf is dull and completely unambiguous, which is what you want at eight in the morning in a shop handling forty jobs.
What to check before you send anything
Open the PDF at full size and look for four things. Does the background run past the crop marks on all four sides. Is every piece of type comfortably inside the safe area. Is any photograph sharp when you zoom to 100%. Are the colours the ones you meant, in the mode the printer asked for.
That is the whole checklist. Everything else a print shop asks about, weight, finish, folding, envelopes, belongs in the print brief rather than the file itself.
Every file that leaves this studio is built this way by default, with bleed, crop marks, safe margins and embedded fonts, alongside flat versions sized for texting and stories. If you are commissioning a custom invitation, you should never have to think about any of the above. If you are working from something you built yourself, now you know what the printer is asking for and why they keep asking.