Tone a photo sepia

A sepia “filter” here is a tone mapped onto lightness. Each pixel keeps the lightness it has and takes the colour the ramp holds at that lightness, so a dark doorway gets the darkest stop's brown and a bright sky the lightest stop's cream. That is what chemical toning did to a silver print, and why it looks right where a flat brown wash does not.

1. Strong chroma at the extremes is reduced to fit sRGB along constant hue, so the deepest shadows and brightest highlights carry less tone than the mid-tones.
2. A tone does not restore faded detail; it only colours the lightness that is there.

Does a colour photo need converting to black and white first?

No. The toning keeps each pixel's lightness and replaces its colour with the tone's colour at that lightness, which discards the original colour in the same pass. Converting first only matters if you want a channel filter to decide the lightness, which the black-and-white page does.

What is split toning?

Two hues instead of one: one laid on the shadows and another on the highlights, meeting in the mid-tones. The balance control moves where one gives way to the other. Choose the Split preset, or add a third stop to any preset for a gradient through the mid-tones.

Which hue is sepia, exactly?

The preset's mid-tone stop sits at an OKLCH hue angle of about 68 degrees, with browner shadows and creamier highlights; the angle is printed in the rail. Sepia is a family rather than one value, so the stops are editable.

• Colourise a monochrome imageMap every visible pixel to one hue while preserving the original luminance structure.
• Make a photo black and whitePerceptual conversion, red to blue filter looks, a three-point curve and a true greyscale PNG.
• Colour splashKeep the colour you tap; everything else turns black and white along the same soft band.

Image data is never posted anywhere: decode, mask, remap and encode all happen inside this tab's memory, and that memory is released when you leave.