Nano Banana 2.1 3:2 print size at 300 dpi: 4.2 to 16.9 inches wide

At 300 dpi a 3:2 Nano Banana 2.1 image prints at 4.2x2.8 inches from the 1K frame, 8.4x5.7 inches from 2K and 16.9x11.3 inches from 4K. A 6x4 inch print needs 1800x1200 pixels, which the 1K frame does not cover, so 2K is the safe tier.

Sume forwards your ratio and tier to the provider and does not document the exact pixels it returns, so this post uses Google's table. Check width and height on the first file you get back before you build a crop on them.

What are the 3:2 sizes and print dimensions?

Pixels are from Google's table. Inches are pixels divided by 300.

Which tier should I pay for?

For a 6x4 inch print at 300 dpi you need 1800x1200 pixels, so the 1K frame at 1264 wide is about 30 percent short and would be upscaled 1.42 times. The 2K frame clears it with room to trim. For anything over 8 inches wide, use 4K or accept a lower dpi: at 150 dpi the 2K frame prints 16.9 inches wide.

• Proof and layout: 1K.
• 4x6 and 5x7 prints: 2K.
• Posters and framed prints: 4K, and check the result at 100 percent before you print.

What does the extra tier cost on Sume?

Billed price on Sume rises from $0.10 at 1K to $0.15 at 2K and $0.20 at 4K, so the jump from a 4.2-inch to a 16.9-inch print is $0.10 per image. Failed generations are not billed. See the image models docs.

{
  "model": "google/nano-banana-2.1",
  "prompt": "Studio photo of a leather camera bag on a wooden table",
  "aspect_ratio": "3:2",
  "resolution": "4K"
}

Does the model embed a dpi?

Do not rely on it. Dpi is a label you set at print time; the pixel dimensions are what the model decides. Set 300 in your editor or print dialog and read the resulting inches.

Print shops often accept a lower dpi for large formats viewed from a distance, so the 150 dpi figure is a fair planning number for a poster, while a handheld 6x4 photo wants the full 300. Ask your printer for the dpi they need and divide the pixel width by it; the 2K frame at 1696 pixels tall gives 5.65 inches at 300 and 11.3 inches at 150.