{"course":{"slug":"image-editing","title":"Editing an Image","url":"https://addaly.com/learn/image-editing","level":"beginner","track":"create"},"lesson":{"slug":"reflections-glare-and-glass","title":"A reflection is a photograph of the light source","url":"https://addaly.com/learn/image-editing/reflections-glare-and-glass","position":44,"of":78,"minutes":9,"answer":"A specular reflection is an image of the light source added on top of the surface, so it can be reduced by subtractive adjustments or replaced from a second frame shot with the reflection moved.","keyIdea":"A specular reflection is an image of the light source added on top of the surface, so it can be reduced by subtractive adjustments or replaced from a second frame shot with the reflection moved, but removing a dense one means inventing what the recorded pixels no longer contain."},"body":{"format":"markdown","text":"## What you are looking at\n\nA specular reflection is not a property of the object. It is an image of whatever is in front of it: the window, the softbox, the room, you and your camera.\n\nThat single fact changes the approach. A reflection cannot be \"cleaned off\" a surface, because underneath it there is no clean version; the recorded pixel is a sum of the surface and the reflection. Removing it means deciding what should have been there and putting that in.\n\nThree things follow:\n\n- The easiest fix is always at capture, by changing what is being reflected.\n- Reducing a reflection is far more achievable than removing it.\n- Removing a large reflection is reconstruction work, with all the honesty questions that carries.\n\n## Fixing it at capture\n\n**Move the light, not the object.** A reflection appears where the angle of incidence equals the angle of reflection. Move the light source thirty degrees and the hot spot moves off the product entirely. This is the whole of product lighting in one sentence.\n\n**Make the source larger and further away.** A big soft source produces a broad, gentle gradient across a glossy surface (which reads as shape) instead of a small hard blob, which reads as a blemish. A window with a net curtain is a large soft source and costs nothing.\n\n**A polarising filter.** Rotating a circular polariser on the lens cuts reflections from non-metallic surfaces (glass, water, plastic, painted wood, foliage) by a substantial amount, and does nothing to reflections from bare metal, because the physics differ. It costs one to two stops of light. For photographing a framed picture, a shop window or water, it is the correct tool and no editing matches it.\n\n**For spectacles**, the professional answer is two frames: one normal, one with the lenses removed from the frames or with the arms lifted so the frames sit higher and the lens reflections move. Composite the eye region from the second frame. Attempting to paint out a reflection across an eye by hand is an hour and looks it.\n\n**For a screen** (a phone or monitor in the shot) shoot the screen off and composite the screen content in afterwards from the actual artwork. Every clean device photograph you have seen was made this way.\n\n## Reducing a reflection in the editor\n\nWhen you have one frame and a reflection that is not too dense.\n\n**The blend-mode approach.** A specular reflection adds light. So work on it with tools that subtract: a Curves layer pulling down, masked precisely to the reflection, is often enough. If the reflection has colour (a blue window reflected on a red bag) a Hue/Saturation layer masked to it, reducing saturation and shifting hue, restores the surface colour underneath.\n\n**Frequency separation.** A soft reflection is almost entirely low frequency. Even it out on the low layer and the surface texture above survives intact. This is the best tool for reflected sheen on leather, fabric and painted metal.\n\n**Clone from a matching area.** On a surface with a consistent finish, another part of the same surface at the same angle gives you correct pixels. Sample carefully; a surface curving away has different shading, and cloning from it produces a visible patch.\n\n**Rebuilding the pattern.** Where the reflection sits over a printed pattern, take the pattern from elsewhere, warp it to fit, and reapply the shading with a burn layer.\n\n## Where removal becomes reconstruction\n\nA dense reflection (a white window across half a black television screen, a whole room reflected in a kettle) has obliterated the information underneath. Every channel in that area is near maximum. There is nothing to recover.\n\nAt that point you are not retouching; you are drawing what you believe was there. That is legitimate for a product's own glossy surface, where you know what it looks like. It is not legitimate when the reflection covers something whose content matters: a document under glass, a face behind a window, the contents of a display case.\n\nThe test from earlier in the course applies: would the viewer be surprised to learn what you did? Rebuilding a kettle's steel finish, no. Inventing what was inside a shop window, yes.\n\n## The two-frame method, generalised\n\nThe most useful technique in this lesson, and it costs nothing.\n\nPut the camera on a tripod or a stack of books. Take one frame. Change what is being reflected: move the lamp, hold a black card between the light and the object, drape a dark cloth behind the camera. Take a second frame.\n\nNow the reflection is in a different place in each frame, and the correct pixels for one are in the other. Load both as layers, align them (the Difference blend mode makes misalignment visible), and mask between them.\n\nThe extreme version of this is **black cloth flagging**: photographing a glossy product with a large piece of black fabric behind the camera, so the object reflects darkness rather than the room. Two metres of black cotton is a few pounds and solves more product photography problems than any filter.\n\n## Free tools, and the limit\n\nNothing here needs paid software. GIMP, Krita and Photopea all have the clone, heal, curves, masks and blend modes required. The polariser and the black cloth are hardware and cheap.\n\nThe honest limit: there is research into single-image reflection removal using neural networks, and there are apps that claim it. On a photograph through a window it sometimes produces a plausible result, and plausible is the operative word: the network is inferring what was behind the glass, not measuring it. For a holiday snapshot through an aeroplane window, fine. For anything where the content behind the glass is the point, what you get back is a guess presented as a photograph, and the earlier lessons on upscaling and denoising apply in exactly the same way."},"check":{"question":"A photographer uses a circular polariser to cut reflections when photographing a display of jewellery in a glass case. The reflections on the glass reduce substantially, but the hot spots on the polished silver do not change at all. Why?","options":[{"text":"The polariser was rotated to the optimal angle for the glass, and metal requires the opposite rotation.","correct":false,"tempting":"Assumes a second optimum exists: rotating further changes which polarisation is blocked, and no angle suppresses a reflection that was never polarised."},{"text":"Reflections from metal surfaces are not polarised in the way reflections from dielectrics are, so a polariser has no reflection to remove there.","correct":true},{"text":"The silver is inside the case, so the polariser only acts on the outermost reflecting surface in the optical path.","correct":false,"tempting":"Invents a depth restriction: the filter acts on all light reaching the lens regardless of how many surfaces it passed through."},{"text":"Specular highlights on metal are brighter than the filter's one to two stops of loss can suppress, so they survive the exposure reduction.","correct":false,"tempting":"Treats the filter as a neutral density reduction rather than a polarisation selector, and the exposure is compensated so relative brightness is unchanged."}]},"prev":{"slug":"product-retouching","title":"The product has to be the product","url":"https://addaly.com/learn/image-editing/product-retouching"},"next":{"slug":"removing-something-large","title":"Rebuild the structure first, then the texture","url":"https://addaly.com/learn/image-editing/removing-something-large"},"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) 'A reflection is a photograph of the light source', in Editing an Image. Edited by M. Mun. Addaly. Available at: https://addaly.com/learn/image-editing/reflections-glare-and-glass (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":"A reflection is a photograph of the light source","courseTitle":"Editing an Image","module":{"index":5,"slug":"repair-and-retouching","title":"Repair and retouching"},"answer":null,"keyIdea":"A specular reflection is an image of the light source added on top of the surface, so it can be reduced by subtractive adjustments or replaced from a second frame shot with the reflection moved, but removing a dense one means inventing what the recorded pixels no longer contain.","hero":{"kind":"plate","image":null,"alt":null,"caption":null},"blocks":[{"t":"h2","id":"what-you-are-looking-at","runs":[{"text":"What you are looking at"}]},{"t":"p","runs":[{"text":"A specular reflection is not a property of the object. It is an image of whatever is in front of it: the window, the softbox, the room, you and your camera."}]},{"t":"p","runs":[{"text":"That single fact changes the approach. A reflection cannot be “cleaned off” a surface, because underneath it there is no clean version; the recorded pixel is a sum of the surface and the reflection. Removing it means deciding what should have been there and putting that in."}]},{"t":"p","runs":[{"text":"Three things follow:"}]},{"t":"ul","items":[[{"text":"The easiest fix is always at capture, by changing what is being reflected."}],[{"text":"Reducing a reflection is far more achievable than removing it."}],[{"text":"Removing a large reflection is reconstruction work, with all the honesty questions that carries."}]]},{"t":"h2","id":"fixing-it-at-capture","runs":[{"text":"Fixing it at capture"}]},{"t":"p","runs":[{"text":"Move the light, not the object.","b":true},{"text":" A reflection appears where the angle of incidence equals the angle of reflection. Move the light source thirty degrees and the hot spot moves off the product entirely. This is the whole of product lighting in one sentence."}]},{"t":"p","runs":[{"text":"Make the source larger and further away.","b":true},{"text":" A big soft source produces a broad, gentle gradient across a glossy surface (which reads as shape) instead of a small hard blob, which reads as a blemish. A window with a net curtain is a large soft source and costs nothing."}]},{"t":"p","runs":[{"text":"A polarising filter.","b":true},{"text":" Rotating a circular polariser on the lens cuts reflections from non-metallic surfaces (glass, water, plastic, painted wood, foliage) by a substantial amount, and does nothing to reflections from bare metal, because the physics differ. It costs one to two stops of light. For photographing a framed picture, a shop window or water, it is the correct tool and no editing matches it."}]},{"t":"p","runs":[{"text":"For spectacles","b":true},{"text":", the professional answer is two frames: one normal, one with the lenses removed from the frames or with the arms lifted so the frames sit higher and the lens reflections move. Composite the eye region from the second frame. Attempting to paint out a reflection across an eye by hand is an hour and looks it."}]},{"t":"p","runs":[{"text":"For a screen","b":true},{"text":" (a phone or monitor in the shot) shoot the screen off and composite the screen content in afterwards from the actual artwork. Every clean device photograph you have seen was made this way."}]},{"t":"h2","id":"reducing-a-reflection-in-the-editor","runs":[{"text":"Reducing a reflection in the editor"}]},{"t":"p","runs":[{"text":"When you have one frame and a reflection that is not too dense."}]},{"t":"p","runs":[{"text":"The blend-mode approach.","b":true},{"text":" A specular reflection adds light. So work on it with tools that subtract: a Curves layer pulling down, masked precisely to the reflection, is often enough. If the reflection has colour (a blue window reflected on a red bag) a Hue/Saturation layer masked to it, reducing saturation and shifting hue, restores the surface colour underneath."}]},{"t":"p","runs":[{"text":"Frequency separation.","b":true},{"text":" A soft reflection is almost entirely low frequency. Even it out on the low layer and the surface texture above survives intact. This is the best tool for reflected sheen on leather, fabric and painted metal."}]},{"t":"p","runs":[{"text":"Clone from a matching area.","b":true},{"text":" On a surface with a consistent finish, another part of the same surface at the same angle gives you correct pixels. Sample carefully; a surface curving away has different shading, and cloning from it produces a visible patch."}]},{"t":"p","runs":[{"text":"Rebuilding the pattern.","b":true},{"text":" Where the reflection sits over a printed pattern, take the pattern from elsewhere, warp it to fit, and reapply the shading with a burn layer."}]},{"t":"h2","id":"where-removal-becomes-reconstruction","runs":[{"text":"Where removal becomes reconstruction"}]},{"t":"p","runs":[{"text":"A dense reflection (a white window across half a black television screen, a whole room reflected in a kettle) has obliterated the information underneath. Every channel in that area is near maximum. There is nothing to recover."}]},{"t":"p","runs":[{"text":"At that point you are not retouching; you are drawing what you believe was there. That is legitimate for a product’s own glossy surface, where you know what it looks like. It is not legitimate when the reflection covers something whose content matters: a document under glass, a face behind a window, the contents of a display case."}]},{"t":"p","runs":[{"text":"The test from earlier in the course applies: would the viewer be surprised to learn what you did? Rebuilding a kettle’s steel finish, no. Inventing what was inside a shop window, yes."}]},{"t":"h2","id":"the-two-frame-method-generalised","runs":[{"text":"The two-frame method, generalised"}]},{"t":"p","runs":[{"text":"The most useful technique in this lesson, and it costs nothing."}]},{"t":"p","runs":[{"text":"Put the camera on a tripod or a stack of books. Take one frame. Change what is being reflected: move the lamp, hold a black card between the light and the object, drape a dark cloth behind the camera. Take a second frame."}]},{"t":"p","runs":[{"text":"Now the reflection is in a different place in each frame, and the correct pixels for one are in the other. Load both as layers, align them (the Difference blend mode makes misalignment visible), and mask between them."}]},{"t":"p","runs":[{"text":"The extreme version of this is "},{"text":"black cloth flagging","b":true},{"text":": photographing a glossy product with a large piece of black fabric behind the camera, so the object reflects darkness rather than the room. Two metres of black cotton is a few pounds and solves more product photography problems than any filter."}]},{"t":"h2","id":"free-tools-and-the-limit","runs":[{"text":"Free tools, and the limit"}]},{"t":"p","runs":[{"text":"Nothing here needs paid software. GIMP, Krita and Photopea all have the clone, heal, curves, masks and blend modes required. The polariser and the black cloth are hardware and cheap."}]},{"t":"p","runs":[{"text":"The honest limit: there is research into single-image reflection removal using neural networks, and there are apps that claim it. On a photograph through a window it sometimes produces a plausible result, and plausible is the operative word: the network is inferring what was behind the glass, not measuring it. For a holiday snapshot through an aeroplane window, fine. For anything where the content behind the glass is the point, what you get back is a guess presented as a photograph, and the earlier lessons on upscaling and denoising apply in exactly the same way."}]}],"check":{"question":[{"text":"A photographer uses a circular polariser to cut reflections when photographing a display of jewellery in a glass case. The reflections on the glass reduce substantially, but the hot spots on the polished silver do not change at all. Why?"}],"options":[{"text":[{"text":"The polariser was rotated to the optimal angle for the glass, and metal requires the opposite rotation."}],"correct":false,"tempting":[{"text":"Assumes a second optimum exists: rotating further changes which polarisation is blocked, and no angle suppresses a reflection that was never polarised."}]},{"text":[{"text":"Reflections from metal surfaces are not polarised in the way reflections from dielectrics are, so a polariser has no reflection to remove there."}],"correct":true,"tempting":null},{"text":[{"text":"The silver is inside the case, so the polariser only acts on the outermost reflecting surface in the optical path."}],"correct":false,"tempting":[{"text":"Invents a depth restriction: the filter acts on all light reaching the lens regardless of how many surfaces it passed through."}]},{"text":[{"text":"Specular highlights on metal are brighter than the filter’s one to two stops of loss can suppress, so they survive the exposure reduction."}],"correct":false,"tempting":[{"text":"Treats the filter as a neutral density reduction rather than a polarisation selector, and the exposure is compensated so relative brightness is unchanged."}]}],"order":[0,1,3,2],"why":null},"prev":{"slug":"product-retouching","title":"The product has to be the product","minutes":9},"next":{"slug":"removing-something-large","title":"Rebuild the structure first, then the texture","minutes":9}}}