Krea 2 Wins the Background

Krea 2 won the background task 2 to 1. Z-Image was sharper, brighter, and faster, but it ignored the instruction that mattered most for a website hero: leave the left third soft and open. The result is a choice between composition and throughput, not a universal model ranking.

The empty third decided the comparison

The test used one nursery prompt and three seeds, rendered through ComfyUI at 1024 square for the direct side by side. The prompt asked for young Artemisia plants in a polytunnel, warm morning light, and an out-of-focus left third with room for text.

Krea followed that layout on seeds 1001 and 2002. Z-Image filled the frame with an aisle and benches on both. Seed 3003 went to Z-Image: it kept the plant detail clean, while Krea's lower edge became milky and its crop tightened on the right.

The saved comparison is six images, not a claim derived from model names. The image sheet and individual outputs are in the ComfyUI A/B receipt set. A second Krea background run at 2048 by 1152 recorded 40 to 44 seconds per eight-step image. The earlier warm Z-Image run recorded 7.5 seconds at its smaller working size. Those timings are useful for planning, but they are not a fair speed contest because the resolutions differ.

The models fail in different directions

Z-Image's failure was compositional. It made the scene legible, crisp, and nearly the same across seeds, but it treated the negative space as optional. That is a bad default for a hero image with copy over it.

Krea's failure was object detail. It introduced black plastic nursery trays beneath the pots and made the Artemisia identity less certain. Its lighting and depth looked more photographic, but the scene needed a prompt correction to remove the trays.

That distinction matters. A model can be better at atmosphere and still be worse for a product claim. The next Krea prompt adds that the terracotta pots stand directly on the wooden bench.

Pick the model after naming the constraint

Choose the model for the failure you can fix in the layout, not the model with the nicest single frame.

What counts as a Krea win:

• the requested empty region survives across seeds;
• the hero can carry text without a crop rescue;
• the lighting and depth support the page's visual hierarchy.

What does not count:

• one attractive seed picked after the fact;
• a quality claim made from different prompts;
• a speed comparison where resolution and warmup differ.

The cost was detail and time

Krea cost sharper plant detail and a longer final render. Its standard eight-step 2048 by 1152 run took 40 to 44 seconds in the saved background batch. Z-Image remained the fast batch tool and the better choice for crisp detail shots.

That trade is acceptable for a hero image. It is not acceptable for exploring dozens of prompt variants. The pipeline now uses Krea for final backgrounds and Z-Image for quick fills and detail passes.

How to prove this wrong

Use the saved nursery prompt, seeds 1001, 2002, and 3003, and the same ComfyUI model files. Hide model names from the reviewer. Count only whether the left third remains useful negative space, then count plant fidelity separately. If Krea wins fewer than two layout comparisons, or if the plant-fidelity result reverses under the same rubric, this post's claim needs correction.

Provenance

One RX 7900 XTX, ComfyUI, Krea 2 Turbo fp8, Qwen3-VL text encoder, Qwen image VAE, eight steps, Euler, simple scheduler, CFG 1.0. Receipts: the saved A/B image set, the shared comparison workflow, and the background render log. The direct comparison was an instrument receipt at 1024 square, while the background batch was 2048 by 1152.

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