{"course":{"slug":"image-editing","title":"Editing an Image","url":"https://addaly.com/learn/image-editing","level":"beginner","track":"create"},"lesson":{"slug":"select-by-colour-properly","title":"Tolerance is a wall, fuzziness is a slope","url":"https://addaly.com/learn/image-editing/select-by-colour-properly","position":24,"of":78,"minutes":8,"answer":"The Magic Wand's tolerance produces an in-or-out selection while Colour Range's fuzziness produces partial values, which is why one is for flat graphics and the other for anything that shades.","keyIdea":"The Magic Wand's tolerance produces an in-or-out selection while Colour Range's fuzziness produces partial values, which is why one is for flat graphics and the other for anything that shades, and neither can separate a subject from a background that shares its values."},"body":{"format":"markdown","text":"## Two colour-based tools that are not the same tool\n\nThe Magic Wand and Colour Range both select by colour, and people use them interchangeably. They compute different things.\n\n**Magic Wand with Tolerance 32** asks, of each pixel: is this within 32 units of the sampled colour? Yes or no. The answer is binary. Every pixel is either fully selected or not selected, and the boundary between them is a step. The only softening you get is the anti-aliasing checkbox and whatever feather you apply afterwards.\n\n**Colour Range with Fuzziness 32** asks: how close is this pixel to the sampled colour? It returns a **partial** selection: a pixel slightly outside the core range is selected at 60 per cent, one further out at 20 per cent. The result has a gradient built in, which is why it produces far better masks on anything that shades.\n\nThat is the practical difference, and it is why Colour Range is the better tool for almost everything except a flat screenshot.\n\n> Figure: Tolerance is a wall, fuzziness is a slope. Line chart of How selected it is, per cent against How far the pixel is from the colour you sampled: Colour Range, fuzziness 32 (0, 100) (16, 78) (32, 50) (48, 22) (64, 4) (80, 0); Magic Wand, tolerance 32 (0, 100) (16, 100) (31, 100) (32, 0) (48, 0) (80, 0). One answers yes or no, so the boundary is a step and the only softness available is the feather you apply afterwards. The other returns partial values, which is what a sky seen through tree branches needs. Neither separates a brown dog from a brown sofa: the numbers genuinely overlap, and no setting invents a difference.\n\nGIMP's equivalents: *Fuzzy Select* (the wand) has a Threshold and a **Draw mask** preview; *Select by Colour* does the same thing non-contiguously. GIMP's threshold is also essentially binary, and its soft equivalent is to build the mask from a decomposed channel instead.\n\n## The controls in Colour Range that matter\n\n*Select > Colour Range* in Photoshop and Photopea.\n\n**Shift-click to add more samples.** One click on a sky selects one blue. A sky runs from pale at the horizon to deep overhead; three or four shift-clicks across it produce a selection that covers all of them. This single habit doubles the tool's usefulness.\n\n**Localized Colour Clusters**, with its Range slider, restricts the selection to pixels *near* where you sampled. Without it, sampling a red dress also selects a red sign on the far side of the frame. With it, you can pick one of two identical red objects.\n\n**The preview dropdown.** Set it to Greyscale and the dialogue shows the mask you are about to make, in black and white, live. Judge it there, not by the marching ants afterwards.\n\n**The preset list** includes Reds, Yellows, Highlights, Midtones, Shadows, Out of Gamut and **Skin Tones**. Skin Tones with *Detect Faces* on is a surprisingly good starting mask for portrait work, not because it is accurate, but because it is 80 per cent right in two seconds and paintable from there.\n\n## Where colour selection is exactly right\n\n- **A sky through tree branches.** No selection tool traces a thousand twigs. Colour Range on the blue does it instantly, and the partial values along each branch are approximately correct.\n- **Changing one colour across a whole frame**: every red item in a catalogue shot, a brand colour on signage.\n- **Selecting out-of-gamut pixels** before a print conversion, to see what is going to clip.\n- **Building a starting mask for a luminosity or colour-specific adjustment**, where you will paint the rest.\n\n## Where it fails, and the mechanism\n\nColour selection fails when subject and background **share colour values**, and no setting fixes that, because the tool has no other information. A brown dog on a brown sofa, a grey car against a grey wall, a white shirt against a white wall: the numbers overlap.\n\nThe diagnosis is quick: look at the three channels individually. If one of them separates subject from background, build from that channel (the previous block's technique). If none of them does, colour is not the route and you need geometry: a path, a painted mask, or a model that understands objects rather than values.\n\nThe second failure is **noise and compression**. A JPEG's 8×8 blocks and a high-ISO file's speckle both mean that visually uniform areas are numerically scattered, so a colour selection comes out with holes and a ragged edge. Applying a one-pixel blur to the image on a duplicate layer before sampling, or blurring the resulting mask, both help; neither is free of cost.\n\n## The free path\n\nGIMP's Fuzzy Select has a useful feature Photoshop lacks: dragging after clicking adjusts the threshold live, with the mask previewed. It is a faster way to find the right value than typing numbers.\n\nFor partial, gradient-aware colour selection, GIMP's route is **Colours > Components > Decompose** to HSV, then work on the hue or saturation layer as a mask. More steps, same result, and it teaches you what the tool is doing.\n\nKrita has *Select Similar Colour* and a *Colour Range* selection, both adequate.\n\n## One caution about recolouring\n\nColour Range is often the first step in changing an object's colour. A warning that belongs here rather than later: a colour selection selects pixels that *are* a colour, including the highlights and shadows on the object, which are the same hue at different lightness. Recolour the selection with a Hue shift and the shading usually survives. Recolour it by painting a flat colour and the object goes dead, because you have replaced its shading with a single tone.\n\nThe method that keeps the shading: a Hue/Saturation layer with the selection as its mask, adjusting Hue rather than painting, or a solid colour layer set to **Colour** blend mode, which takes the hue from the fill and the luminosity from the photograph. That second one is the standard trick and it takes ten seconds.\n\nAnd the honest limit on all of it: changing a red car to yellow works; changing a black car to yellow does not, because black has no hue to shift and no shading information in the colour channels to preserve. Dark and desaturated objects have to be repainted with the tone rebuilt by hand, which is a job of a different size."},"check":{"question":"An editor uses Colour Range to select a black leather bag so they can recolour it tan, and finds that neither a Hue shift nor a Colour-mode fill produces a convincing tan bag. Why?","options":[{"text":"Colour Range cannot sample dark values, so the selection itself is empty and nothing is being recoloured.","correct":false,"tempting":"Claims a sampling limit that does not exist: the tool samples any value including near-black, and returns a usable selection there."},{"text":"Black pixels carry almost no hue or saturation to shift, and the shading that would define a tan surface has to be rebuilt by painting rather than remapped.","correct":true},{"text":"Colour blend mode takes luminosity from the layer below, and leather has too much specular highlight for that mode to work on any colour.","correct":false,"tempting":"Describes the mode correctly then blames the wrong property: specular highlights are precisely what Colour mode preserves well on a mid-toned object."},{"text":"The bag needs to be selected with Localized Colour Clusters enabled, because without it the selection includes other dark areas and dilutes the adjustment.","correct":false,"tempting":"Names a real setting that improves which pixels are chosen without touching the reason a hue shift on near-black produces no colour."}]},"prev":{"slug":"quick-mask-and-painting-a-selection","title":"Stop fighting the selection tools and paint it","url":"https://addaly.com/learn/image-editing/quick-mask-and-painting-a-selection"},"next":{"slug":"luminosity-masks","title":"Masks with no edge anywhere","url":"https://addaly.com/learn/image-editing/luminosity-masks"},"authorship":"Founder and series editor: Dr Mustafa Mun. Written by AI models to a written standard. Exam keys checked blind by a second model: 3,665 of 3,666 agreed. Academic review invited.","review":{"status":"Draft, open for academic review"},"cite":"Addaly (2026) 'Tolerance is a wall, fuzziness is a slope', in Editing an Image. Edited by M. Mun. Addaly. Available at: https://addaly.com/learn/image-editing/select-by-colour-properly (Accessed: 13 October 2026).","licence":{"name":"CC BY-NC-SA 4.0","url":"https://creativecommons.org/licenses/by-nc-sa/4.0/"},"reader":{"schema":1,"title":"Tolerance is a wall, fuzziness is a slope","courseTitle":"Editing an Image","module":{"index":3,"slug":"selections-cutouts-and-edges","title":"Selections, cut-outs and edges"},"answer":null,"keyIdea":"The Magic Wand’s tolerance produces an in-or-out selection while Colour Range’s fuzziness produces partial values, which is why one is for flat graphics and the other for anything that shades, and neither can separate a subject from a background that shares its values.","hero":{"kind":"figure","figure":{"t":"figure","label":"Figure","figure":{"type":"line","title":"Tolerance is a wall, fuzziness is a slope","series":[{"label":"Colour Range, fuzziness 32","points":[[0,100],[16,78],[32,50],[48,22],[64,4],[80,0]]},{"label":"Magic Wand, tolerance 32","points":[[0,100],[16,100],[31,100],[32,0],[48,0],[80,0]]}],"xLabel":"How far the pixel is from the colour you sampled","yLabel":"How selected it is, per cent","caption":"One answers yes or no, so the boundary is a step and the only softness available is the feather you apply afterwards. The other returns partial values, which is what a sky seen through tree branches needs. Neither separates a brown dog from a brown sofa: the numbers genuinely overlap, and no setting invents a difference."},"alt":"Figure: Tolerance is a wall, fuzziness is a slope. Line chart of How selected it is, per cent against How far the pixel is from the colour you sampled: Colour Range, fuzziness 32 (0, 100) (16, 78) (32, 50) (48, 22) (64, 4) (80, 0); Magic Wand, tolerance 32 (0, 100) (16, 100) (31, 100) (32, 0) (48, 0) (80, 0). One answers yes or no, so the boundary is a step and the only softness available is the feather you apply afterwards. The other returns partial values, which is what a sky seen through tree branches needs. Neither separates a brown dog from a brown sofa: the numbers genuinely overlap, and no setting invents a difference."}},"blocks":[{"t":"h2","id":"two-colour-based-tools-that-are-not-the-same-tool","runs":[{"text":"Two colour-based tools that are not the same tool"}]},{"t":"p","runs":[{"text":"The Magic Wand and Colour Range both select by colour, and people use them interchangeably. They compute different things."}]},{"t":"p","runs":[{"text":"Magic Wand with Tolerance 32","b":true},{"text":" asks, of each pixel: is this within 32 units of the sampled colour? Yes or no. The answer is binary. Every pixel is either fully selected or not selected, and the boundary between them is a step. The only softening you get is the anti-aliasing checkbox and whatever feather you apply afterwards."}]},{"t":"p","runs":[{"text":"Colour Range with Fuzziness 32","b":true},{"text":" asks: how close is this pixel to the sampled colour? It returns a "},{"text":"partial","b":true},{"text":" selection: a pixel slightly outside the core range is selected at 60 per cent, one further out at 20 per cent. The result has a gradient built in, which is why it produces far better masks on anything that shades."}]},{"t":"p","runs":[{"text":"That is the practical difference, and it is why Colour Range is the better tool for almost everything except a flat screenshot."}]},{"t":"p","runs":[{"text":"GIMP’s equivalents: "},{"text":"Fuzzy Select","i":true},{"text":" (the wand) has a Threshold and a "},{"text":"Draw mask","b":true},{"text":" preview; "},{"text":"Select by Colour","i":true},{"text":" does the same thing non-contiguously. GIMP’s threshold is also essentially binary, and its soft equivalent is to build the mask from a decomposed channel instead."}]},{"t":"h2","id":"the-controls-in-colour-range-that-matter","runs":[{"text":"The controls in Colour Range that matter"}]},{"t":"p","runs":[{"text":"Select > Colour Range","i":true},{"text":" in Photoshop and Photopea."}]},{"t":"p","runs":[{"text":"Shift-click to add more samples.","b":true},{"text":" One click on a sky selects one blue. A sky runs from pale at the horizon to deep overhead; three or four shift-clicks across it produce a selection that covers all of them. This single habit doubles the tool’s usefulness."}]},{"t":"p","runs":[{"text":"Localized Colour Clusters","b":true},{"text":", with its Range slider, restricts the selection to pixels "},{"text":"near","i":true},{"text":" where you sampled. Without it, sampling a red dress also selects a red sign on the far side of the frame. With it, you can pick one of two identical red objects."}]},{"t":"p","runs":[{"text":"The preview dropdown.","b":true},{"text":" Set it to Greyscale and the dialogue shows the mask you are about to make, in black and white, live. Judge it there, not by the marching ants afterwards."}]},{"t":"p","runs":[{"text":"The preset list","b":true},{"text":" includes Reds, Yellows, Highlights, Midtones, Shadows, Out of Gamut and "},{"text":"Skin Tones","b":true},{"text":". Skin Tones with "},{"text":"Detect Faces","i":true},{"text":" on is a surprisingly good starting mask for portrait work, not because it is accurate, but because it is 80 per cent right in two seconds and paintable from there."}]},{"t":"h2","id":"where-colour-selection-is-exactly-right","runs":[{"text":"Where colour selection is exactly right"}]},{"t":"ul","items":[[{"text":"A sky through tree branches.","b":true},{"text":" No selection tool traces a thousand twigs. Colour Range on the blue does it instantly, and the partial values along each branch are approximately correct."}],[{"text":"Changing one colour across a whole frame","b":true},{"text":": every red item in a catalogue shot, a brand colour on signage."}],[{"text":"Selecting out-of-gamut pixels","b":true},{"text":" before a print conversion, to see what is going to clip."}],[{"text":"Building a starting mask for a luminosity or colour-specific adjustment","b":true},{"text":", where you will paint the rest."}]]},{"t":"h2","id":"where-it-fails-and-the-mechanism","runs":[{"text":"Where it fails, and the mechanism"}]},{"t":"p","runs":[{"text":"Colour selection fails when subject and background "},{"text":"share colour values","b":true},{"text":", and no setting fixes that, because the tool has no other information. A brown dog on a brown sofa, a grey car against a grey wall, a white shirt against a white wall: the numbers overlap."}]},{"t":"p","runs":[{"text":"The diagnosis is quick: look at the three channels individually. If one of them separates subject from background, build from that channel (the previous block’s technique). If none of them does, colour is not the route and you need geometry: a path, a painted mask, or a model that understands objects rather than values."}]},{"t":"p","runs":[{"text":"The second failure is "},{"text":"noise and compression","b":true},{"text":". A JPEG’s 8×8 blocks and a high-ISO file’s speckle both mean that visually uniform areas are numerically scattered, so a colour selection comes out with holes and a ragged edge. Applying a one-pixel blur to the image on a duplicate layer before sampling, or blurring the resulting mask, both help; neither is free of cost."}]},{"t":"h2","id":"the-free-path","runs":[{"text":"The free path"}],"role":"free"},{"t":"p","runs":[{"text":"GIMP’s Fuzzy Select has a useful feature Photoshop lacks: dragging after clicking adjusts the threshold live, with the mask previewed. It is a faster way to find the right value than typing numbers."}]},{"t":"p","runs":[{"text":"For partial, gradient-aware colour selection, GIMP’s route is "},{"text":"Colours > Components > Decompose","b":true},{"text":" to HSV, then work on the hue or saturation layer as a mask. More steps, same result, and it teaches you what the tool is doing."}]},{"t":"p","runs":[{"text":"Krita has "},{"text":"Select Similar Colour","i":true},{"text":" and a "},{"text":"Colour Range","i":true},{"text":" selection, both adequate."}]},{"t":"h2","id":"one-caution-about-recolouring","runs":[{"text":"One caution about recolouring"}]},{"t":"p","runs":[{"text":"Colour Range is often the first step in changing an object’s colour. A warning that belongs here rather than later: a colour selection selects pixels that "},{"text":"are","i":true},{"text":" a colour, including the highlights and shadows on the object, which are the same hue at different lightness. Recolour the selection with a Hue shift and the shading usually survives. Recolour it by painting a flat colour and the object goes dead, because you have replaced its shading with a single tone."}]},{"t":"p","runs":[{"text":"The method that keeps the shading: a Hue/Saturation layer with the selection as its mask, adjusting Hue rather than painting, or a solid colour layer set to "},{"text":"Colour","b":true},{"text":" blend mode, which takes the hue from the fill and the luminosity from the photograph. That second one is the standard trick and it takes ten seconds."}]},{"t":"p","runs":[{"text":"And the honest limit on all of it: changing a red car to yellow works; changing a black car to yellow does not, because black has no hue to shift and no shading information in the colour channels to preserve. Dark and desaturated objects have to be repainted with the tone rebuilt by hand, which is a job of a different size."}]}],"check":{"question":[{"text":"An editor uses Colour Range to select a black leather bag so they can recolour it tan, and finds that neither a Hue shift nor a Colour-mode fill produces a convincing tan bag. Why?"}],"options":[{"text":[{"text":"Colour Range cannot sample dark values, so the selection itself is empty and nothing is being recoloured."}],"correct":false,"tempting":[{"text":"Claims a sampling limit that does not exist: the tool samples any value including near-black, and returns a usable selection there."}]},{"text":[{"text":"Black pixels carry almost no hue or saturation to shift, and the shading that would define a tan surface has to be rebuilt by painting rather than remapped."}],"correct":true,"tempting":null},{"text":[{"text":"Colour blend mode takes luminosity from the layer below, and leather has too much specular highlight for that mode to work on any colour."}],"correct":false,"tempting":[{"text":"Describes the mode correctly then blames the wrong property: specular highlights are precisely what Colour mode preserves well on a mid-toned object."}]},{"text":[{"text":"The bag needs to be selected with Localized Colour Clusters enabled, because without it the selection includes other dark areas and dilutes the adjustment."}],"correct":false,"tempting":[{"text":"Names a real setting that improves which pixels are chosen without touching the reason a hue shift on near-black produces no colour."}]}],"order":[0,3,2,1],"why":null},"prev":{"slug":"quick-mask-and-painting-a-selection","title":"Stop fighting the selection tools and paint it","minutes":8},"next":{"slug":"luminosity-masks","title":"Masks with no edge anywhere","minutes":9}}}