Image colour is changed without applying any operations

[Juneezee]

Possible bug

Is this a possible bug in a feature of sharp, unrelated to installation?

• Running npm install sharp completes without error.
• Running node -e "require('sharp')" completes without error.

If you cannot confirm both of these, please open an installation issue instead.

Are you using the latest version of sharp?

• I am using the latest version of sharp as reported by npm view sharp dist-tags.latest.

If you cannot confirm this, please upgrade to the latest version and try again before opening an issue.

If you are using another package which depends on a version of sharp that is not the latest, please open an issue against that package instead.

What is the output of running npx envinfo --binaries --system --npmPackages=sharp --npmGlobalPackages=sharp?

  System:
    OS: Linux 6.17 Arch Linux
    CPU: (16) x64 AMD Ryzen 7 PRO 4750U with Radeon Graphics
    Memory: 15.66 GB / 22.84 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 24.10.0 - /home/jun/.nvm/versions/node/v24.10.0/bin/node
    npm: 11.6.1 - /home/jun/.nvm/versions/node/v24.10.0/bin/npm

Does this problem relate to file caching?

The default behaviour of libvips is to cache input files, which can lead to EBUSY or EPERM errors on Windows.
Use sharp.cache(false) to switch this feature off.

• Adding sharp.cache(false) does not fix this problem.

Does this problem relate to images appearing to have been rotated by 90 degrees?

Images that contain EXIF Orientation metadata are not auto-oriented. By default, EXIF metadata is removed.

• To auto-orient pixel values use the parameter-less rotate() operation.

• To retain EXIF Orientation use keepExif().

• Using rotate() or keepExif() does not fix this problem.

What are the steps to reproduce?

1. Download the provided original.jpg
2. Copy the provided minimal reproducible code below into main.mjs file. This file should be in the same directory as original.jpg.
3. Run node main.mjs.

What is the expected behaviour?

The colour of the image should not change.

Please provide a minimal, standalone code sample, without other dependencies, that demonstrates this problem

import { readFileSync, writeFileSync } from "node:fs";
import sharp from "sharp";

const buf = readFileSync("original.jpg");
const s = sharp(buf);
const newBuf = await s.toBuffer();
writeFileSync("processed.jpg", newBuf);

Please provide sample image(s) that help explain this problem

Original image:

Processed image:

[lovell]

The sample input image provided is in the CMYK colourspace with an ICC profile. If you wish to retain this same profile and colourspace in the output, rather than the default behaviour of converting to profile-less sRGB, please see https://sharp.pixelplumbing.com/api-output/#keepiccprofile

[Juneezee]

The sample input image provided is in the CMYK colourspace with an ICC profile. If you wish to retain this same profile and colourspace in the output, rather than the default behaviour of converting to profile-less sRGB, please see https://sharp.pixelplumbing.com/api-output/#keepiccprofile

@lovell I just tried. Even with keepIccprofile(), the colour is still different.

[lovell]

Ah, sorry, you'll need to explicitly add toColourspace('cmyk') to maintain CMYK colourspace in the output image.

https://sharp.pixelplumbing.com/api-colour/#tocolourspace

(I might need to update the keepIccProfile docs as there have been some recent upstream changes in libvips around how colourspaces and profiles are handled when saving.)

[Juneezee]

Ah, sorry, you'll need to explicitly add toColourspace('cmyk') to maintain CMYK colourspace in the output image.

@lovell With toColourspace('cmyk').keepIccProfile(), the colour is still different.

I also noticed that WebStorm reports the original image as having 32-bit colour, while the processed image only has 24-bit colour.

Below are the outputs of magick inspect --verbose from ImageMagick for both the original and processed images.

Original image:

Image:
  Filename: original.jpg
  Permissions: rw-r--r--
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 1654x1169+0+0
  Resolution: 100x100
  Print size: 16.54x11.69
  Units: PixelsPerInch
  Colorspace: CMYK
  Type: ColorSeparation
  Base type: Undefined
  Endianness: Undefined
  Depth: 8-bit
  Channels: 4.0
  Channel depth:
    Cyan: 8-bit
    Magenta: 8-bit
    Yellow: 8-bit
    Black: 8-bit
  Channel statistics:
    Pixels: 1933526
    Cyan:
      min: 210  (0.823529)
      max: 255 (1)
      mean: 252.624 (0.990681)
      median: 254 (0.996078)
      standard deviation: 3.12871 (0.0122694)
      kurtosis: 4.25942
      skewness: -1.83013
      entropy: 0.542567
    Magenta:
      min: 36  (0.141176)
      max: 200 (0.784314)
      mean: 141.508 (0.554935)
      median: 136 (0.533333)
      standard deviation: 23.5531 (0.092365)
      kurtosis: -0.702555
      skewness: 0.453851
      entropy: 0.896817
    Yellow:
      min: 0  (0)
      max: 51 (0.2)
      mean: 5.75338 (0.0225623)
      median: 5 (0.0196078)
      standard deviation: 4.62731 (0.0181463)
      kurtosis: 0.0165718
      skewness: 0.648222
      entropy: 0.739265
    Black:
      min: 0  (0)
      max: 167 (0.654902)
      mean: 25.3131 (0.0992672)
      median: 20 (0.0784314)
      standard deviation: 21.0454 (0.0825309)
      kurtosis: 0.892005
      skewness: 1.08159
      entropy: 0.836792
  Image statistics:
    Overall:
      min: 0  (0)
      max: 255 (1)
      mean: 106.3 (0.416861)
      median: 103.75 (0.406863)
      standard deviation: 13.0886 (0.0513279)
      kurtosis: 1.11636
      skewness: 0.0883836
      entropy: 0.75386
  Total ink density: 253.725%
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33,0.03)
    green primary: (0.3,0.6,0.1)
    blue primary: (0.15,0.06,0.79)
    white point: (0.3127,0.329,0.3583)
  Matte color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: black
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1654x1169+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 96
  Orientation: TopLeft
  Profiles:
    Profile-8bim: 3538 bytes
    Profile-exif: 1507 bytes
    Profile-iptc: 25 bytes
      City[1,90]: 0x00000000: 254700                                        -%G
      unknown[2,0]:
      Image Name[2,5]: Print
    Profile-xmp: 4708 bytes
  Properties:
    date:create: 2025-10-31T09:36:22+00:00
    date:modify: 2025-10-31T09:36:06+00:00
    date:timestamp: 2025-11-02T17:27:09+00:00
    exif:BitsPerSample: 8, 8, 8, 8
    exif:ColorSpace: 65535
    exif:DateTime: 2023:04:12 11:10:36
    exif:ExifOffset: 236
    exif:ExifVersion: 0231
    exif:ImageLength: 3508
    exif:ImageWidth: 4961
    exif:PhotometricInterpretation: 5
    exif:PixelXDimension: 1654
    exif:PixelYDimension: 1169
    exif:SamplesPerPixel: 4
    exif:Software: Adobe Photoshop 24.3 (Windows)
    exif:thumbnail:Compression: 6
    exif:thumbnail:JPEGInterchangeFormat: 386
    exif:thumbnail:JPEGInterchangeFormatLength: 1115
    exif:thumbnail:ResolutionUnit: 2
    exif:thumbnail:XResolution: 72/1
    exif:thumbnail:YResolution: 72/1
    jpeg:colorspace: 4
    jpeg:sampling-factor: 1x1,1x1,1x1,1x1
    signature: 2890372682892ea595a79948cfeb89a9ba3266475f3c9ea51c287a6164abcb10
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 1.97452MiB
  Number pixels: 1.93353M
  Pixel cache type: Memory
  Pixels per second: 23.0365MP
  User time: 0.080u
  Elapsed time: 0:01.083
  Version: ImageMagick 7.1.2-8 Q16-HDRI x86_64 2300ae543:20251025 https://imagemagick.org

Processed image:

Note

I have no idea why the Colorspace field is still sRGB even when toColourspace('cmyk') is set.

Image:
  Filename: processed.jpg
  Permissions: rw-r--r--
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 1654x1169+0+0
  Units: Undefined
  Colorspace: sRGB
  Type: TrueColor
  Base type: Undefined
  Endianness: Undefined
  Depth: 8-bit
  Channels: 3.0
  Channel depth:
    Red: 8-bit
    Green: 8-bit
    Blue: 8-bit
  Channel statistics:
    Pixels: 1933526
    Red:
      min: 0  (0)
      max: 32 (0.12549)
      mean: 2.51997 (0.00988225)
      median: 2 (0.00784314)
      standard deviation: 2.93445 (0.0115076)
      kurtosis: 1.71212
      skewness: 1.31988
      entropy: 0.606245
    Green:
      min: 22  (0.0862745)
      max: 126 (0.494118)
      mean: 77.5976 (0.304304)
      median: 82 (0.321569)
      standard deviation: 16.2868 (0.06387)
      kurtosis: -0.710247
      skewness: -0.641201
      entropy: 0.875237
    Blue:
      min: 91  (0.356863)
      max: 188 (0.737255)
      mean: 144.056 (0.564926)
      median: 148 (0.580392)
      standard deviation: 14.2468 (0.05587)
      kurtosis: -0.437819
      skewness: -0.745231
      entropy: 0.861213
  Image statistics:
    Overall:
      min: 0  (0)
      max: 188 (0.737255)
      mean: 74.7246 (0.293038)
      median: 77.3333 (0.303268)
      standard deviation: 11.156 (0.0437492)
      kurtosis: 0.188019
      skewness: -0.0221852
      entropy: 0.780899
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33,0.03)
    green primary: (0.3,0.6,0.1)
    blue primary: (0.15,0.06,0.79)
    white point: (0.3127,0.329,0.3583)
  Matte color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: black
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1654x1169+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 80
  Orientation: Undefined
  Profiles:
    Profile-icc: 480 bytes
  Properties:
    date:create: 2025-11-02T17:27:01+00:00
    date:modify: 2025-11-02T17:27:01+00:00
    date:timestamp: 2025-11-02T17:28:03+00:00
    icc:copyright: CC0
    icc:description: sRGB
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: db19ccdd85fc06b5d6f73bce8563da39e8510a96c6478c926648f9186a408f02
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 197048B
  Number pixels: 1.93353M
  Pixel cache type: Memory
  Pixels per second: 78.8921MP
  User time: 0.020u
  Elapsed time: 0:01.024
  Version: ImageMagick 7.1.2-8 Q16-HDRI x86_64 2300ae543:20251025 https://imagemagick.org

[lovell]

Thanks, I've been able to reproduce locally and can see that the expected output is CMYK but the actual output is RGB. Commit e1628d8 simplifies some of the logic around this and adds the scenario from this issue as a test cases to help prevent regression.

[lovell]

There's a release candidate available if you'd like to test.

npm i sharp@v0.34.5-rc.0

[Juneezee]

There's a release candidate available if you'd like to test.

npm i sharp@v0.34.5-rc.0

@lovell I install the release candidate and followed the updated comments of commit e1628d8. In my case toColourspace("cmyk") isn't enough, pipelineColourspace("cmyk") must also be used.

import { readFileSync, writeFileSync } from "node:fs";
import sharp from "sharp";

const buf = readFileSync("original.jpg");
const s = sharp(buf)
	.pipelineColourspace("cmyk")
	.toColourspace("cmyk")
	.keepIccProfile();
const newBuf = await s.toBuffer();
writeFileSync("processed.jpg", newBuf);

Image:
  Filename: processed.jpg
  Permissions: rw-r--r--
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 1654x1169+0+0
  Units: Undefined
  Colorspace: CMYK
  Type: ColorSeparation
  Base type: Undefined
  Endianness: Undefined
  Depth: 8-bit
  Channels: 4.0
  Channel depth:
    Cyan: 8-bit
    Magenta: 8-bit
    Yellow: 8-bit
    Black: 8-bit
  Channel statistics:
    Pixels: 1933526
    Cyan:
      min: 221  (0.866667)
      max: 255 (1)
      mean: 252.54 (0.990353)
      median: 253 (0.992157)
      standard deviation: 2.38092 (0.00933693)
      kurtosis: 4.27696
      skewness: -1.73582
      entropy: 0.581343
    Magenta:
      min: 40  (0.156863)
      max: 202 (0.792157)
      mean: 141.51 (0.554941)
      median: 136 (0.533333)
      standard deviation: 23.5807 (0.0924733)
      kurtosis: -0.714126
      skewness: 0.446926
      entropy: 0.898469
    Yellow:
      min: 0  (0)
      max: 53 (0.207843)
      mean: 5.79022 (0.0227068)
      median: 5 (0.0196078)
      standard deviation: 4.15623 (0.0162989)
      kurtosis: 1.11321
      skewness: 0.969187
      entropy: 0.732562
    Black:
      min: 0  (0)
      max: 166 (0.65098)
      mean: 25.4264 (0.0997113)
      median: 20 (0.0784314)
      standard deviation: 21.1147 (0.0828029)
      kurtosis: 1.03726
      skewness: 1.12899
      entropy: 0.833843
  Image statistics:
    Overall:
      min: 0  (0)
      max: 255 (1)
      mean: 106.317 (0.416928)
      median: 103.5 (0.405882)
      standard deviation: 12.8081 (0.050228)
      kurtosis: 1.42833
      skewness: 0.202321
      entropy: 0.761554
  Total ink density: 257.647%
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33,0.03)
    green primary: (0.3,0.6,0.1)
    blue primary: (0.15,0.06,0.79)
    white point: (0.3127,0.329,0.3583)
  Matte color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: black
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 1654x1169+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 80
  Orientation: Undefined
  Properties:
    date:create: 2025-11-06T01:27:15+00:00
    date:modify: 2025-11-06T01:27:15+00:00
    date:timestamp: 2025-11-06T01:28:09+00:00
    jpeg:colorspace: 4
    jpeg:sampling-factor: 1x1,1x1,1x1,1x1
    signature: b2d2d7bdd4cabad2da8f478c0712330f1bb014a2671718b6291cee9640681916
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 998098B
  Number pixels: 1.93353M
  Pixel cache type: Memory
  Pixels per second: 35.831MP
  User time: 0.050u
  Elapsed time: 0:01.053
  Version: ImageMagick 7.1.2-8 Q16-HDRI x86_64 2300ae543:20251025 https://imagemagick.org

Thanks for fixing the issue 😊