QiLing Tools

🎦Film Negative to Positive Converter - Remove Orange Mask

Simply inverting a scanned or camera-scanned colour negative gives a flat, cyan-blue picture, because colour film carries an orange mask and its three dye layers have different contrast. This converter follows how film actually works. It finds the film base colour — automatically, from the clearest unexposed part of the strip, or with an eyedropper on the gap between frames — divides each channel by it and takes the logarithm to get density, then sets black and white points for red, green and blue separately, a lite version of Negative Lab Pro’s auto balance that removes the mask and the cast in one go, and finally maps density back to natural tones using the chosen density range. After that, click something neutral with the white balance eyedropper and fine-tune temperature, tint, exposure, contrast, shadows, highlights and saturation. Dust removal finds the small bright specks left by dust, hairs and fine scratches and fills them from the surrounding pixels. Crop off the rebate, rotate in 90° steps and flip if the strip was scanned the wrong way round. B&W negatives are inverted with tone controls only, and slides skip inversion entirely. A whole roll can be processed in one batch with the preview frame’s levels, at full resolution in a Web Worker, exported as JPG or PNG — all locally, nothing is uploaded.

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How to use Film Negative Converter

  1. 1Drop your scanned or camera-scanned negatives (several at once is fine) and choose colour negative, B&W negative or slide
  2. 2Let the film base be detected or sample it on the rebate, then refine with the white balance eyedropper, exposure and tone; add dust removal, crop and rotation
  3. 3Pick JPG or PNG and convert; download a batch as a ZIP

FAQ

Why do my inverted negatives look blue and flat?
Colour negative film has an orange mask in its base that compensates for impure dyes, and its cyan, magenta and yellow layers have different contrast (gamma). A plain inversion turns the orange into a strong cyan-blue cast and leaves each channel’s tones misaligned. Dividing by the film base colour removes the mask, and setting separate black and white points per channel in the density domain gives a correctly coloured positive.
How do I sample the film base?
Auto-detect is usually enough: it looks for the clearest (brightest in the scan) part of the strip and ignores sprocket holes and bare backlight. If the scan is cropped tight with no rebate, or the result has a cast, click “Sample the film border” and then click an unexposed orange area between two frames or along the film edge in the preview.
How do I keep a whole roll consistent?
In a batch, tick “reuse the preview image’s levels”: every frame then uses the film base and black/white points of the frame you are previewing, so shots from the same roll and light match. Untick it to auto-balance each frame on its own, which suits a mixed batch from different films or lighting. A sampled film base is always shared across the batch.
Will dust removal erase real detail?
It only touches small spots that are clearly brighter (negatives) or darker (slides) than their surroundings, found with a morphological opening and filled with a weighted average of nearby pixels; higher strength finds more. At very high strength genuine small highlights such as stars or specular glints can be treated as dust, so start around 30 and compare the preview. Heavy scratches still need dedicated software or infrared dust removal.