Upscale Only

Use the Upscale Only workflow when you only need to enlarge images in bulk (for example, before manual cleanup, printing, or archiving) and do not need detection, OCR, translation, inpainting, or layout rendering. It sends each input image through the upscaler and writes the main output image directly, without producing translated text or entering the mask, inpainting, and rendering stages.

Upscale Only belongs to the same bypass family as Colorize Only and Inpaint Only: all of them skip the second half of the translation pipeline and differ only in which pre-stage they keep. The overall boundaries of the nine workflows are in Output Directory and Workflow, with a summary table in Workflow Matrix; the upscaling model, ratio, and tiling parameters are described in Upscaling and Colorization.

When to use it

• Inputs: the main input images (the same file-discovery rules as normal translation: Add Files, Add Folder, or drag-and-drop; folders are searched recursively in natural sort order and directories named manga_translator_work are skipped).
• Stages executed: colorize (conditional) → upscale (conditional). Colorization runs first when colorizer.colorizer is not none; upscaling runs when upscale.upscale_ratio has a value.
• Stages skipped: detection, OCR, text-line merge, translation, mask refinement, inpainting, and layout rendering. The upscale_only branch clears text_regions so the translation and rendering branches are never entered.
• Output files: the main output image (its path is computed by the output-path rules, see Related Files and Formats); when either colorization or upscaling is active, the editor base image manga_translator_work/editor_base/<original-filename> is written as well.
• Workflow field: combo index 6 writes cli.upscale_only=true at runtime; GUI switching keeps the eight workflow booleans mutually exclusive.

Upscale Only does not force a ratio: upscale_only=true only decides which stages are skipped, while whether the image is actually enlarged is decided by upscale_ratio. When the ratio is empty, the output is the colorized result (if the colorizer is on) or the original image. The source code also does not turn colorization off in this mode, so the UI hint "only upscale images" is not fully consistent with the actual pre-colorization when a colorizer is enabled.

Run this workflow

Select the Upscale Only workflow

1. Open the translation page and choose “Upscale Only” in the “Translation Workflow Mode:” combo box.
2. The page title becomes “Upscale Only” and the subtitle shows the hint: only upscale images, no detection, OCR, translation or rendering.
3. The start button becomes “Start Upscaling”; clicking it starts the backend task in this mode.

Selecting a mode only writes configuration and updates the UI texts; it does not start a task. Before starting, add the main input images (“Add Files...”, “Add Folder...”, or drag-and-drop) and, if needed, choose the upscaling model and ratio under “Settings → Mode Specific → Upscaling”; when the ratio stays at “Not Use”, this mode does not change the image.

Processing order

Processing branches and outputs

The desktop task enters the standard or high-quality batch loop through translate_batch(), and each image goes through _translate_until_translation() for conditional colorization and conditional upscaling. The upscale_only branch returns directly with ctx.result = ctx.upscaled after upscaling, so the subsequent detection, OCR, translation, and rendering stages are skipped as a whole.

flowchart TD
    A["Input image"] --> B{"colorizer != none?"}
    B -->|no| C["Skip colorization"]
    B -->|yes| D["Run colorization"]
    C --> E{"upscale_ratio set?"}
    D --> E
    E -->|no| F["Skip upscaling"]
    E -->|yes| G["Run upscaling"]
    F --> H["upscale_only branch"]
    G --> H
    H --> I["result = upscaled / colorized / original"]
    I --> J["Main output image"]
    I --> K["editor_base image<br/>(when colorize or upscale active)"]
    I --> L["Project JSON<br/>(save_text default on, empty regions)"]

The diagram shows the branches of Upscale Only: an empty ratio still outputs the colorized image or the original; the editor base image is written only when colorizer != none or upscale_ratio is set; and the project-JSON write depends on cli.save_text/text_output_file (see Dependencies and Conflicts) and is subject to the actual output. This mode does not become a concurrent pipeline just because the UI still stores the concurrent setting.

Inputs, outputs, and limitations

• upscale_only=true does not force a ratio: when upscale_ratio is “Not Use” (null), the output is the colorized result or the original image; the UI hint and the actual code behavior are not fully consistent (the code does not turn colorization off).
• Pre-colorization: when colorizer.colorizer is not none, Upscale Only still runs colorization first, incurring model, VRAM, and API costs; with an empty ratio the output keeps that colorized result.
• revert_upscaling only restores the output size; it does not cancel upscaling. The image is enlarged and then downscaled, so upscaling computation still happens.
• tile_size=0 only disables tiling; it does not disable upscaling. An empty value uses the runtime default 400.
• cli.overwrite=false: the GUI skips images whose main output image already exists before starting (the “normal mode” branch checks the output image).
• cli.save_text: the default is true. The batch loop calls _save_text_to_file even when text_regions is empty, as long as save_text or text_output_file is enabled, so with default settings Upscale Only also writes a project JSON with empty regions (recording upscale_ratio, upscaler, and last_export_dir). The research matrix lists only the main image and the editor base image as outputs; actual file retention needs the actual output.
• batch_concurrent is incompatible: both the desktop controller and translate_batch() treat Upscale Only as an incompatible mode and force non-concurrent processing.
• Manually combining multiple workflow fields is not a supported combination; GUI switching keeps the eight fields mutually exclusive, and core dispatch does not rely on stacked fields.
• The main output directory, save_to_source_dir, and cli.format determine the main output image location and extension; the JSON and editor base image always follow the per-image work-directory rules and are not affected by the output directory.
• This mode does not render, so it does not write skip_text_replacements; paint/stamp overlay layers in an existing JSON are preserved.

Read next

• Other workflows: Normal Translation · Export Original Text · Export Translation · Translate JSON Only · Import Translation and Render · Colorize Only · Inpaint Only · Replace Translation
• Selecting a workflow, output directory, and mutually exclusive writes: Output Directory and Workflow
• Inputs, skipped stages, and outputs of all nine workflows: Workflow Matrix
• Mutually exclusive workflow fields, parameter overrides, and template alignment: Mode-Specific Workflows and Template Alignment

See the reference index: Workflow Matrix.