Bulk Threshold to Black and White Free
Runs 100% in your browser — your files never leave your device.
Turn a folder of sketches into line art, make a batch of stencils, or create high-contrast masks for many images in a single pass. One threshold cutoff is applied to every file, and all the processing happens locally in your browser.
How it works
- 1
Add your images
Drop one or more JPG, PNG, or WebP files into the box. Nothing is uploaded.
- 2
Threshold the batch
Set the control once — it is applied to every file in the batch.
- 3
Download the results
Process the batch, then download each edited image individually.
About this tool
Batch threshold workflows
Turn a folder of pencil sketches into print-ready line art, build a full sheet of stencils, or prepare many scans for a laser cutter in one pass. Craft and fabrication workflows run on consistent thresholds across whole sets. For one image at a time, the single-image threshold tool does the same job.
One setting, every file
One threshold cutoff drives the whole batch: set it once and every image receives the identical threshold treatment — the same pipeline the single-image version runs, applied to each file in turn. Nothing is uploaded: the batch is processed on your device, originals are never modified, and you download each finished image individually in its original format.
Frequently asked questions
How many images can the batch handle?
As many as your browser can hold in memory — dozens of typical photos are routine. Very large batches simply take proportionally longer, and every file is processed on your own device.
Is the batch result identical to the single-image threshold tool?
Yes — every file runs through the same threshold pipeline as the single-image version. One setting drives all of them; nothing is averaged or compromised across the batch.
My scans have different brightness levels — will one cutoff work?
Maybe not. Scans of similar paper and lighting share a cutoff happily; mixed sources need it. Test the cutoff on the darkest and lightest scans first, and split the batch if the extremes disagree.