One file per frame ratio: 2:3, 3:4, 4:5, 11×14, and ISO

I used to upload one poster and write "print at any size" in the description. Then a buyer put a tall vocabulary poster into a frame that was much closer to a square. The title disappeared. The poster was not wrong. The frame shape was different, and one rectangle cannot fill every frame without a cut or a border.

A ratio is just the relationship of the two sides. If you double both sides, the ratio stays the same. That is why 8×12, 16×24, and 24×36 can share one file. They are all 2:3. A frame that is not 2:3 needs its own file if you want the whole design to show.

The shapes I actually prepare

2:3. Divide the short side by the long side and you get 2 divided by 3, about 0.67. Common inch sizes in this family are 4×6, 8×12, 12×18, 16×24, and 24×36. At 300 dots in each inch, 24×36 is 7200 × 10800 pixels. If I design the poster for this shape, the same artwork can be scaled to the smaller 2:3 sizes without a new crop. The title stays in the same place relative to the edge.

3:4. The short side divided by the long side is 0.75. Sizes I see a lot are 6×8, 9×12, 12×16, and 18×24. At 300 dots per inch, 18×24 is 5400 × 7200 pixels. This is wider than 2:3. A 24×36 design dropped onto an 18×24 sheet will lose a strip at the top and bottom, or it will have empty bars on the sides if you refuse to crop.

4:5. This one is 0.8. The familiar sizes are 4×5, 8×10, and 16×20. At 300 dots per inch, 8×10 is 2400 × 3000, and 16×20 is 4800 × 6000. People sometimes treat 8×10 and 11×14 as twins. They are not.

11×14. Eleven divided by fourteen is about 0.786. Four divided by five is 0.8. Those numbers are close, which is why a buyer hopes one file will do both. Close is not the same. An 8×10 design placed in an 11×14 frame must be cropped a little or surrounded by a margin. On a poster with a border of Spanish phrases, "a little" can remove the last word on a line.

ISO A. A4, A3, A2, and the rest share one ratio: the long side is the short side times the square root of two, about 1.414. Fold an A4 in half the long way and you get A5. Two A4 sheets side by side make A3. Because the ratio stays put, one A-series file can scale between those papers without a new crop. The pixel targets are not round inch numbers. An A4 sheet is 210 by 297 millimetres. Divide by 25.4 to get inches, about 8.27 by 11.69, then multiply by 300. Rounded to the nearest pixel, A4 at 300 dots per inch is 2480 × 3508. A3 is 3508 × 4961. I do not call an A4 file an 8.5×11 file. Letter paper in the United States is a different shape.

How I build the set

I design the most important size first, usually the one I expect people to print. I put the title and any must-keep words inside a safe area, not kissing the edge. Then I make a new artboard for each ratio I plan to sell. I move the pieces so the title still has room. I do not only scale. Scaling a 2:3 poster to be wider is a crop or a redesign. Calling it a scale hides the cut.

For each artboard I export pixels with the 300 rule. I name the file with the size and the ratio, using only letters, numbers, periods, underscores, or hyphens, because that is the kind of name a buyer can live with. "vocabulario-18x24-3x4.png" tells the truth. "final-FINAL-v7.png" does not.

If I am short on time, I would rather ship three correct ratios than six files that are the same crop with a new name. A buyer who owns an 11×14 frame and an 8×10 frame will notice if I handed them one picture twice.

Borders versus cuts

Sometimes I do want one master design and several frames. Then I choose a border on purpose. The artwork stays complete, and the paper color fills the gap. That is a real product choice. It is different from a surprise crop. In the listing I say "the design sits inside the sheet with a margin" when that is what the file does. I say "the design fills the sheet" only when I checked that nothing important was cut.

Classroom posters are harsh tests. Children stand close. Parents photograph the print and zoom in. A title sliced in half looks like a mistake even if the illustration is lovely. I would rather add a quiet margin than lose "Los animales del bosque" off the bottom.

What I check before upload

I open every file, not only the first. I confirm the pixel size matches the name. I look at all four edges for clipped words. I print one letter page at home when the design has small type, so I see ink on paper and not only a glowing screen.

The print-crop part of this site is built for this exact job: one picture, several ratios, and the largest size each ratio can be from the pixels you have. It does not silently enlarge a short file and still call it the biggest sharp print. If your poster has a title, look at the frame before you export, and keep a separate file for each shape you promise.