BYTETOOLS

Film Negative to Positive Converter

Turn a scanned colour negative into a positive. Samples the orange film base, cancels the mask and stretches each channel's histogram.

Drop a scanned colour negative — include the unexposed frame edge if you canProcessed locally in your browser — never uploaded

What is the Film Negative to Positive Converter?

Scanning a colour negative gives you more than an inverted picture — the film has an orange mask baked into its base, so a straight invert comes out heavily blue and flat.

  • One-step inversion and orange-mask removal by mapping each channel against the film base
  • Automatic base sampling from the frame border, plus click-to-sample and a hex input
  • Optional per-channel histogram stretch with adjustable black and white clip percentages
  • Shows the sampled base R, G and B values and the clip points it landed on
  • Works on colour negatives, black-and-white negatives and scanned slides
  • Processed locally in your browser — your scans are never uploaded

How to use the Film Negative to Positive Converter

  1. 1

    Drop in a scan of your colour negative, ideally including the unexposed strip along the frame edge.

  2. 2

    Click that orange unexposed strip on the original to set the film base colour, or press “Sample from frame border”.

  3. 3

    Leave the per-channel histogram stretch on for normal colour negatives.

  4. 4

    Adjust the black and white clip percentages if the result looks flat or if highlights are blowing out.

  5. 5

    Check the positive and click Download PNG.

About the Film Negative to Positive Converter

Scanning a colour negative gives you more than an inverted picture — the film has an orange mask baked into its base, so a straight invert comes out heavily blue and flat. The fix is to measure the colour of the unexposed film base and map every channel against it, which inverts the frame and cancels the mask in one step.

The tool samples that base colour from the frame border automatically the moment you drop a scan in, and you can click the unexposed orange strip yourself to set it exactly, or type a hex value. Each channel is then mapped so the film base lands on pure black and clear film on pure white.

An optional per-channel histogram stretch pushes the darkest and brightest few percent of each channel out to the ends of the range, which is what recovers contrast and neutral colour. Everything happens on a canvas in your browser, and your scans are never uploaded.

Frequently asked questions

Why is my inverted negative so blue?

Colour negative film has an orange mask in its base that corrects for dye imperfections during printing. Simply inverting the scan turns that orange into a strong blue cast across the whole frame; you have to divide by the base colour to cancel it.

Where do I find the film base colour?

It is the unexposed area of the strip — the rebate along the edge of the frame, or a completely clear section between shots. Scan it along with the image if you can, then click it in the preview so the tool measures the real base rather than guessing.

What if my scan has no frame border?

Sample the brightest, most orange area you can find — in a negative that corresponds to the deepest shadow of the scene, which is closest to bare film base. Then rely on the histogram stretch to finish the job, and adjust the hex value by eye.

Does this work for black-and-white negatives?

Yes. There is no orange mask to cancel, so set the base colour to a neutral grey matching the film base density and let the per-channel stretch handle the contrast. The result is usually cleaner than converting a colour negative.

What do the black and white clip percentages do?

They set how much of each channel is allowed to be crushed to pure black or blown to pure white when the histogram is stretched. Half a percent each is a safe default; raising them adds punch at the cost of losing detail in the extremes.

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