October 6, 2026
Printing an AI image large: how many pixels, which upscale, what price
The exact pixels to aim for on A4, A3, A2, 50 × 70 cm, 18 × 24 in or A0, at 300, 200 or 150 dpi. What image models output, when generating in 4K is cheaper than upscaling and when it is the other way round, and the full chain that takes an AI image to a 50 × 70 cm poster for 39 credits.
Frank HoubreFounder of Imaginode
An AI image is 1 to 16 megapixels, a poster needs 50
A 1024 × 1024 image printed at 300 dpi measures 8.7 centimeters, about 3.4 inches, on each side: for a poster, pixels are almost always missing, and the question is how many.
The misunderstanding starts on screen. An image generated at 1024 pixels looks superb on a monitor, because a monitor shows about a hundred pixels per inch. A printer puts down around three hundred in the same inch. The same image, printed properly, fits in the palm of your hand: 8.7 centimeters, or 3.4 inches, on a side.
For a crisp A4 or US Letter sheet held in the hand, you need about 8.5 megapixels. For a 50 × 70 cm poster at the same standard, close to 49. Image models output between 1 and 16 megapixels depending on the model and the tier you pick. The gap is closed in two ways: generate at the highest tier, then upscale what is missing.
This guide gives the exact numbers for common formats, what each option costs on Imaginode, and the printing pitfalls that have nothing to do with pixels but ruin just as many posters.
300 dpi, 200 or 150: it all depends on distance
300 dpi for anything looked at in the hand, a flyer, a photo, a book; 150 to 200 dpi for a poster seen from more than a meter away; 100 dpi and below for a banner or a mural seen from afar.
Dpi, dots per inch, tells you how many image pixels land in 2.54 centimeters of paper. Printers use 300 as the standard for a simple reason: at reading distance, about thirty centimeters, the eye can no longer tell pixels apart beyond that. For a business card, an invitation, a photo print, a book, aim for 300.
But nobody reads a poster from thirty centimeters. At one meter, 150 dpi is enough for the image to look perfectly sharp; at three meters, 100 dpi. That is why advertising banners and twelve-foot billboards are printed at definitions that would make a photographer wince, without anyone on the street noticing.
One precaution all the same: ask your print shop what it expects. Many require 300 dpi at final size on principle, whatever the medium. A file that follows their instruction saves you a round trip, and that is often what tips the balance toward an upscale rather than a 150 dpi file.
The pixels to aim for, format by format
A4: 2480 × 3508 at 300 dpi. A3: 3508 × 4961. A2: 4961 × 7016. 50 × 70 cm: 5906 × 8268 at 300 dpi or 2953 × 4134 at 150. 18 × 24 in: 5400 × 7200 at 300 dpi. A0: 4967 × 7022 at 150 dpi.
The math fits on one line: inches times the target dpi, or millimeters divided by 25.4 times the dpi. Here are the results for the formats people print most. At 300 dpi: an A5 needs 1748 × 2480 pixels, an A4 2480 × 3508, an A3 3508 × 4961, an A2 4961 × 7016. In US sizes, a Letter sheet needs 2550 × 3300, an 8 × 10 print 2400 × 3000, an 11 × 17 tabloid 3300 × 5100. A 4 × 6 photo print, 1200 × 1800.
For poster formats, look at the two definitions that matter. An 18 × 24 inch poster needs 5400 × 7200 pixels at 300 dpi, 2700 × 3600 at 150. A 50 × 70 cm poster needs 5906 × 8268 at 300 dpi, or 48.8 megapixels, and 2953 × 4134 at 150 dpi. A 24 × 36 inch poster, 7200 × 10800 at 300 dpi, 3600 × 5400 at 150. An A0, 9933 × 14043 at 300 dpi, or 139.5 megapixels, and 4967 × 7022 at 150.
Add bleed if the image runs to the edge of the paper: usually three millimeters, an eighth of an inch, on each side, or about 35 pixels per side at 300 dpi. That is the margin the printer trims, and an image that stops exactly at the format ends up with a white sliver.
What image models output
At the 1K tier an image is about one megapixel, 2048 pixels wide at the 2K tier, and Seedream 5 Lite's 4K comes out at 4096 × 4096 square and 3072 × 4096 in 3:4, measured in real generations.
Tier names are misleading, so let's start from measurements. At the base tier, a square comes out at 1024 × 1024: enough for 3.4 inches at 300 dpi. At the 2K tier, 2048 × 2048: a 6.8-inch square. At the 4K tier of Seedream 5 Lite, 4096 × 4096 square and 3072 × 4096 in 3:4 portrait: an A4 or Letter page at 300 dpi with room to spare, or an A3 at about 250 dpi.
OpenAI models only know three sizes, 1024 × 1024, 1536 × 1024 and 1024 × 1536: excellent for text in the image, they will almost always go through an upscale before printing. Each model's details are in which format and resolution to generate.
One thing to remember: no image model outputs a 50 × 70 cm or 18 × 24 inch poster at 300 dpi directly. For anything larger than A3 or tabloid, upscaling is part of the chain, not a patch.
Generate in 4K or upscale: the price model by model
Seedream 5 Lite costs 5 credits in 4K as in 2K, so always generate in 4K; Flux 3 costs 115 credits in 4K against 19 in 1K upscaled 4x; Nano Banana Pro costs 34 in 4K against 31 in 2K upscaled, almost the same price.
The simplest case first: Seedream 5 Lite charges the same for 4K as for 2K, 5 credits. There is no reason to generate below it. It is the best starting point for a print when a photorealistic style fits.
At the other end, Flux 3 charges a lot for resolution: 7 credits in 1K, 34 in 2K, 115 in 4K. Generating in 1K then upscaling four times with Topaz Precision gives a 4096 × 4096 image for 7 plus 12, or 19 credits, six times less than native 4K. Native will have more fine detail, the upscale will cost far less: for a poster seen from a meter away, the upscale is very often enough.
In between, Nano Banana Pro costs 19 credits in 2K and 34 in 4K; 2K upscaled twice comes to 31. With three credits between them, take native 4K: the model decides the details itself instead of leaving an upscaler to guess them. Nano Banana 2 points the same way, 22 credits in 4K against 15 plus 12 for 2K upscaled. The general rule: look at the price of the higher tier before upscaling, it is sometimes cheaper than the upscale.
BalanceChoosing the upscale factor
A 3072 × 4096 image in 3:4 upscaled 2x becomes 6144 × 8192, or 50 megapixels: enough to print an A2 or an 18 × 24 inch poster at 300 dpi or more, a 50 × 70 cm at 297 dpi, an A1 at about 250 dpi and an A0 at about 175.
Start from the most common good starting point, a 3:4 image of 3072 × 4096 pixels. Upscaled twice, it becomes 6144 × 8192, just over 50 megapixels. That covers an A2 at 300 dpi, an 18 × 24 inch poster at 341 dpi since it is exactly the same 3:4 ratio, a 50 × 70 cm at 297 dpi, an A1 at about 250 dpi and an A0 at about 175 dpi. In other words, every poster you hang in a room.
A 4x of the same image would give 201 megapixels, beyond the 100-megapixel output ceiling of the Enhance node. That is not a limitation that gets in the way: no common format needs more, and a 200-megapixel file is a nightmare to send to a print shop. For an A0 at 300 dpi, 139.5 megapixels, the printer will tell you themselves that 150 to 200 dpi is enough at that size.
On a 1024-pixel image, the reasoning flips: 4x is needed to reach 4096 pixels, and in faithful mode it costs nothing more than 2x, 12 credits either way. Factors and billing blocks are detailed in AI upscaling: faithful or creative.
Faithful or creative for a print
For a generated image seen up close, creative mode adds texture that shows on paper, but it costs 292 credits for 50 megapixels against 34 in faithful mode; for a real photo, only faithful is acceptable.
Print is the one place where the difference between the two modes is obvious to everyone. On screen, you look at an image as a whole. On a poster, people step closer, and fifty centimeters from a 50 × 70 they see the texture. Faithful mode can leave surfaces a little smooth, creative mode puts grain, stone and fabric into them.
The price, however, is another story. For our 6144 × 8192 image, Topaz Precision costs 34 credits and Topaz Bloom 2 292 credits, since it is billed per 2-megapixel block instead of 24. On an illustration, a landscape, an invented movie poster, creative can be worth that price. On a photo of your family or your product, never: it changes faces and details, as we measured on a family photo.
A compromise that works well: generate at the highest tier with the model that produces the most detail, then upscale in faithful mode. The detail comes from the generation, the size comes from the upscale, and the bill stays reasonable.
The paper's ratio is not the image's ratio
A sizes have a 1.414 ratio, 3:4 is 1.333 and 50 × 70 cm is 1.4: a 3:4 image placed on an A2 loses about 6% of its width when cropped, or needs to be extended.
A sizes are built so that an A3 folded in half gives two A4s: their height-to-width ratio is the square root of two, 1.414. No image model offers that ratio. The closest is 3:4, 1.333, while the 2:3 of photo prints and 24 × 36 inch posters, 1.5, falls on the other side. The good news for US formats: 18 × 24 inches is exactly 3:4.
In practice, a 3:4 image printed on an A2 using the full height overflows by 6% in width: you trim three percent on each side. If nothing important sits near the edges, that is the simplest fix. If the framing is tight, it is better to add scenery: extend an image lengthens the scene consistently, and the upscale comes after. The 50 × 70 cm, at 1.4, is almost an A size: the same 3:4 image loses only 5% of its width.
Decide on the paper format before generating, exactly as you decide on a social format before the prompt. A composition designed to be cropped at the top and bottom is not designed to be cropped at the sides.
The pitfalls that have nothing to do with pixels
Neon colors outside the printer's gamut, an image that prints too dark, invented text, no bleed: those are what ruin the most posters, not the definition.
Colors first. A screen displays in RGB, a printer lays down ink in CMYK, and some saturated screen colors simply do not exist in ink: electric blues, fluorescent greens, neon magentas, all very common in AI images. They will come out duller. If your visual relies on a vivid color, ask for a proof or generate a less saturated version.
Brightness next. A screen is lit from inside, paper is lit by the room. A dark, contrasty image, gorgeous on screen, often prints with blocked-up shadows. Lifting the shadows slightly before sending the file avoids the bad surprise. And proofread every word in the image at 100%: an upscaler does not fix a typo, and creative mode can even create one, a problem covered in AI hands and text problems.
Finally the bleed, mentioned earlier: three millimeters on each side, which the printer will trim. Plan for it in the framing and keep anything important at least a centimeter from the edge. The same rule applies to a business card, an invitation or a poster.
The full chain: a 50 × 70 cm poster for 39 credits
An Image node with Seedream 5 Lite in 4K at 3:4, for 5 credits, then an Enhance node with Topaz Precision 2x, for 34 credits: 6144 × 8192 pixels, a 50 × 70 cm poster at 297 dpi or an 18 × 24 inch one at 341.
On the canvas, the chain fits in two nodes. An Image node set to Seedream 5 Lite, 4K tier, 3:4 format, which outputs 3072 × 4096 for 5 credits. You generate, you choose, you retouch if needed. Then an Enhance node wired to its output, in Image mode, Topaz Precision, 2x factor: 6144 × 8192 pixels for 34 credits. The file goes to the print shop.
If your poster needs exact text, a title, a date, a venue, generate it with a model that is strong on text and upscale afterwards; the poster maker starts with the right settings. For a painting to hang, photo to painting turns a photo into a painting, and for a whole wall, wall mural and wallpaper, where 100 dpi is plenty seen from across the room.
And for the everyday A4 or Letter page, coloring sheets, handouts, invitations, a 4K tier is enough without any upscale. The pages from printable coloring pages come out ready for A4 that way, in pure black line art that does not waste ink.
The summary
Choose the dpi by viewing distance, work out the pixels for the format, generate at the highest tier when it is cheap, upscale what is missing in faithful mode, and check colors, text and bleed before sending.
Numbers to keep: 300 dpi in the hand, 150 to 200 dpi for a poster, 100 for a wall. A4 at 300 dpi, 8.7 megapixels. Letter, 8.4. A3, 17.4. 18 × 24 inches, 38.9. 50 × 70 cm, 48.8. A 2x upscale of a 3:4 image 4096 pixels tall covers every indoor poster.
Prices to keep: Seedream 5 Lite in 4K at 5 credits, Topaz Precision at 12 credits up to 24 megapixels and 34 up to 72, Topaz Bloom 2 reserved for invented images that will be seen up close. Always check the price of a model's 4K tier before upscaling.
And for a video rather than an image, the same reasoning with its own numbers is in AI video in 4K. The calculator prices the whole thing before you run anything.