Editing GIMP (section)

== Features ==
{{Further|Comparison of raster graphics editors}}
[[File:Cycle of gradients brushes pratterns in gimp-2.8.gif|thumb|Animation Showing Brushes, Patterns, Gradients Created in GIMP]]Tools used to perform image editing can be accessed via the toolbox, through menus and dialogue windows. They include filters and brushes, as well as transformation, selection, [[Layers (digital image editing)|layer]] and masking tools. GIMP's developers have asserted that it has, or at least aspire to it having, similar functionality to Photoshop, but has a different user interface.<ref>{{cite web |title=GIMP Developers Conference 2006 |url=http://developer.gimp.org/gimpcon/2006/index.html#vision |date=2006 |publisher=The GIMP Project |website=Developer.Gimp.org |access-date=2 July 2009 |archive-date=3 March 2012 |archive-url=https://web.archive.org/web/20120303082402/http://developer.gimp.org/gimpcon/2006/index.html#vision }}</ref>

=== Color ===
There are several ways of selecting colors, including palettes, color choosers and using an eyedropper tool to select a color on the canvas. The built-in color choosers include [[RGB color model|RGB]]/[[HSL and HSV|HSV]]/[[CIELAB color space|LAB]]/[[HCL color space|LCH]] selector or scales, water-color selector, [[CMYK color model|CMYK]] selector and a color-wheel selector. Colors can also be selected using hexadecimal color codes, as used in HTML color selection. GIMP has native support for indexed color and [[RGB color model|RGB]] color spaces; other color spaces are supported using decomposition, where each channel of the new color space becomes a black-and-white image. CMYK, [[Lab color space|LAB]] and [[HSL and HSV|HSV]] ([[hue]], [[Colorfulness|saturation]], [[Lightness|value]]) are supported this way.<ref>{{cite web |title=Separate+ |url=http://cue.yellowmagic.info/softwares/separate.html |last=Yamakawa |first=Yoshinori |date=6 January 2007 |website=Cue.YellowMagic.info |archive-url=https://web.archive.org/web/20070107080439/http://cue.yellowmagic.info/softwares/separate.html |archive-date=7 January 2007 |access-date=2 July 2009 }}</ref><ref>{{cite web |title=Decompose |url=http://docs.gimp.org/2.6/en/plug-in-decompose-registered.html |website=Docs.Gimp.org |access-date=2 July 2009 |archive-date=24 December 2013 |archive-url=https://web.archive.org/web/20131224115305/http://docs.gimp.org/2.6/en/plug-in-decompose-registered.html |url-status=live }}</ref> Color blending can be achieved using the Blend tool, by applying a [[Image gradient|gradient]] to the surface of an image and using GIMP's color modes. Gradients are also integrated into tools such as the brush tool, when the user paints this way the output color slowly changes. There are a number of default gradients included with GIMP; a user can also create custom gradients with tools provided. Gradient plug-ins are also available.

=== Selections and paths ===
GIMP [[selection (user interface)|selection]] tools include a rectangular and circular selection tool, free select tool, and fuzzy select tool (also known as magic wand). More advanced selection tools include the select by color tool for selecting contiguous regions of color—and the scissors select tool, which creates selections semi-automatically between areas of highly contrasting colors. GIMP also supports a quick mask mode where a user can use a brush to paint the area of a selection. Visibly this looks like a red colored overlay being added or removed. The foreground select tool is an implementation of [[Simple interactive object extraction]] (SIOX), a method used to perform the extraction of foreground elements, such as a person or a tree in focus. The Paths Tool allows a user to create vectors (also known as [[Bézier curve]]s). Users can use paths to create complex selections, including around natural curves. They can paint (or "stroke") the paths with brushes, patterns, or various line styles. Users can name and save paths for reuse.

=== Image editing ===
There are many tools that can be used for editing images in GIMP. The more common tools include a paint brush, pencil, airbrush, eraser and ink tools used to create new or blended pixels. The Bucket Fill tool can be used to fill a selection with a color or pattern. The Blend tool can be used to fill a selection with a color gradient. These color transitions can be applied to large regions or smaller custom path selections.

GIMP also provides "smart" tools that use a more complex algorithm to do things that otherwise would be time-consuming or impossible. These include:
* Clone tool, which copies pixels using a brush
* Healing brush, which copies pixels from an area and corrects tone and color
* Perspective clone tool, which works like the clone tool but corrects for distance changes
* Blur and sharpen tools
* The Smudge tool can be used to subtly smear a selection where it stands
* Dodge and burn tool is a brush that makes target pixels lighter (dodges) or darker (burns)

[[File:Cycle of layers channels paths in gimp-2.8.gif|thumb|Animation showing three docked and tabbed dialogs: layers, channels, and paths]]

=== Layers, layer masks and channels ===
An image being edited in GIMP can consist of many [[Layers (digital image editing)|layers]] in a stack. The user manual suggests that "A good way to visualize a GIMP image is as a stack of transparencies," where in GIMP terminology, each level (analogous to a transparency) is called a layer.<ref>{{cite web |title=Introduction to layers |url=http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-concepts-layers |website=Docs.Gimp.org |access-date=2 July 2009 |archive-date=7 October 2013 |archive-url=https://web.archive.org/web/20131007071617/http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-concepts-layers |url-status=live }}</ref> Each layer in an image is made up of several channels. In an [[RGB color model|RGB]] image, there are normally 3 or 4 channels, each consisting of a red, green and blue channel. Color sublayers look like slightly different gray images, but when put together they make a complete image. The fourth channel that may be part of a layer is the [[Alpha compositing|alpha channel]] (or layer mask). This channel measures opacity where a whole or part of an image can be completely visible, partially visible or invisible. Each layer has a layer mode that can be set to change the colors in the image.<ref>{{cite web |title=Layer Modes |url=http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-concepts-layers |website=Docs.Gimp.org |access-date=2 July 2009 |archive-date=7 October 2013 |archive-url=https://web.archive.org/web/20131007071617/http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-concepts-layers |url-status=live }}</ref>

Text layers can be created using the text tool, allowing a user to write on an image. Text layers can be transformed in several ways, such as converting them to a path or selection.<ref>{{cite web |title=Paths and Text |url=http://docs.gimp.org/ca/gimp-concepts-layer-modes.html |website=Docs.Gimp.org |access-date=16 February 2014 |archive-date=22 February 2014 |archive-url=https://web.archive.org/web/20140222133214/http://docs.gimp.org/ca/gimp-concepts-layer-modes.html |url-status=live }}</ref><ref>{{cite web |title=Text and Fonts |url=http://docs.gimp.org/2.6/en/gimp-concepts-text.html |website=Docs.Gimp.org |access-date=5 July 2009 |archive-date=7 October 2013 |archive-url=https://web.archive.org/web/20131007202529/http://docs.gimp.org/2.6/en/gimp-concepts-text.html |url-status=live }}</ref>

[[File:Droste Daisy.jpg|thumb|[[Droste effect]] using Mathmap plug-in]]

=== Automation, scripts and plug-ins ===
GIMP has approximately 150 standard effects and filters, including Drop Shadow, Blur, Motion Blur and Noise.

GIMP operations can be automated with [[scripting language]]s. The Script-Fu is a [[Scheme (programming language)|Scheme]]-based language implemented using a [[TinyScheme]] interpreter built into GIMP.<ref>{{cite web |title=Using Script-Fu Scripts |url=http://docs.gimp.org/2.8/en/gimp-concepts-script-fu.html |website=Docs.Gimp.org |access-date=26 May 2014 |archive-date=7 June 2014 |archive-url=https://web.archive.org/web/20140607075758/http://docs.gimp.org/2.8/en/gimp-concepts-script-fu.html |url-status=live }}</ref> GIMP can also be scripted in [[Perl]],<ref>{{cite web |title=Basic Perl |url=http://www.gimp.org/tutorials/Basic_Perl/ |website=Gimp.org |access-date=26 May 2014 |archive-date=27 May 2014 |archive-url=https://web.archive.org/web/20140527220212/http://www.gimp.org/tutorials/Basic_Perl/ |url-status=live }}</ref><ref>{{cite web |title=GIMP Perl source |url=https://git.gnome.org/browse/gimp-perl |website=GNOME git repository |access-date=26 May 2014 |archive-date=23 December 2014 |archive-url=https://web.archive.org/web/20141223004855/https://git.gnome.org/browse/gimp-perl/ |url-status=live }}</ref> [[Python (programming language)|Python]] (Python-Fu),<ref>{{cite web |title=GIMP Python Documentation |url=http://www.gimp.org/docs/python/ |website=Gimp.org |archive-url=https://web.archive.org/web/20140615063302/http://www.gimp.org/docs/python/ |archive-date=15 June 2014 |access-date=26 May 2014}}</ref><ref>{{cite web |title=GIMP Python source |url=https://git.gnome.org/browse/gimp/tree/plug-ins/pygimp/plug-ins |website=GNOME git repository |access-date=26 May 2014 |archive-date=7 August 2011 |archive-url=https://web.archive.org/web/20110807023959/http://git.gnome.org/browse/gimp/tree/plug-ins/pygimp/plug-ins |url-status=live }}</ref> or [[Tcl]], using interpreters external to GIMP.<ref>{{cite web |title=Gimp Client |url=http://wiki.tcl.tk/11232 |website=wiki.tcl.tk website |access-date=26 May 2014 |archive-date=27 May 2014 |archive-url=https://web.archive.org/web/20140527212750/http://wiki.tcl.tk/11232 |url-status=live }}</ref> New features can be added to GIMP not only by changing program code (GIMP core), but also by creating plug-ins. These are external programs that are executed and controlled by the main GIMP program.<ref>{{cite web |title=Plug-In Development |url=http://developer.gimp.org/plug-ins.html |website=Developer.Gimp.org |access-date=26 May 2014 |archive-date=15 June 2014 |archive-url=https://web.archive.org/web/20140615033820/http://developer.gimp.org/plug-ins.html }}</ref><ref>{{Cite CiteSeerX |date=4 December 2006 |first1=Earl |last1=Oliver |first2=Jaime |last2=Ruiz |first3=Steven |last3=She |first4=Jun |last4=Wang |title=The Software Architecture of the GIMP |citeseerx=10.1.1.84.7715 }}</ref> MathMap is an example of a plug-in written in [[C (programming language)|C]]. <ref>{{cite web |title=MathMap |url=https://github.com/schani/mathmap |website=Github |publisher=Github |access-date=30 May 2025}}</ref>

There is support for several methods of sharpening and blurring images, including the blur and sharpen tool. The [[Unsharp masking#Digital unsharp masking|unsharp mask]] tool is used to sharpen an image selectively&nbsp;– it sharpens only those areas of an image that are sufficiently detailed. The Unsharp Mask tool is considered to give more targeted results for photographs than a normal sharpening filter.<ref>{{cite web |title=Sharpening – Unsharp Mask |url=http://www.scantips.com/simple6.html |website=ScanTips.com |access-date=8 August 2009 |archive-date=5 October 2013 |archive-url=https://web.archive.org/web/20131005054153/http://www.scantips.com/simple6.html |url-status=live }}</ref><ref>{{cite web |title=Unsharp Mask |url=http://manual.gimp.org/en/plug-in-unsharp-mask.html |website=GIMP manual |archive-url=https://archive.today/20060502225017/http://manual.gimp.org/en/plug-in-unsharp-mask.html |archive-date=2 May 2006 |access-date=8 August 2009 }}</ref> The Selective Gaussian Blur tool works in a similar way, except it blurs areas of an image with little detail.

GIMP-ML is an extension for machine learning with 15 filters.<ref>{{cite web |url=https://github.com/kritiksoman/GIMP-ML |title=kritiksoman/GIMP-ML |date=14 May 2021 |access-date=16 May 2021 |via=GitHub |archive-date=8 May 2021 |archive-url=https://web.archive.org/web/20210508164721/https://github.com/kritiksoman/gimp-ml |url-status=live }}</ref>

=== GEGL ===
The ''[[GEGL|Generic Graphics Library]]'' (''GEGL'') was first introduced in GIMP 2.6 to improve how the software processes images.  Initially GIMP used GEGL for high bit-depth colour operations, helping reduce data loss when adjusting colours.<ref>{{cite web |title=GIMP 2.6 Release Notes |url=http://gimp.org/release-notes/gimp-2.6.html |website=Gimp.org |access-date=2 July 2009 |archive-date=7 October 2013 |archive-url=https://web.archive.org/web/20131007191623/http://www.gimp.org/release-notes/gimp-2.6.html |url-status=live }}</ref>

GIMP 2.8 was limited to 8-bit color, which is much lower than the 12-bit or higher depth that most digital cameras produce. GIMP 2.10 introduced full support for high bit-depth color, and hardware acceleration was enabled through OpenCL for some tasks.<ref>{{cite web |title=Hacking:Porting Filters to GEGL |publisher=The GIMP Project |url=http://wiki.gimp.org/wiki/Hacking:Porting_filters_to_GEGL |website=Wiki.Gimp.org |archive-url=https://web.archive.org/web/20220205071048/http://wiki.gimp.org/wiki/Hacking:Porting_filters_to_GEGL |archive-date=5 February 2022 |access-date=12 April 2023 }}</ref>

GIMP 3.0 introduces non-destructive filters, allowing users to apply effects without permanently changing the original image. This means they can be edited, toggled on or off, or removed after being applied. Third-party filters are also supported, though they will not be retained if the necessary plugins are missing.<ref>{{cite web |title=GIMP 3.0 Release Notes |url=https://www.gimp.org/release-notes/gimp-3.0.html#non-destructive-layer-effects |website=GIMP |publisher=GIMP Development Team |date=16 March 2025 |access-date=18 March 2025}}</ref>

=== CTX ===
CTX is a [[Rasterisation|rasterizer]] for vector graphics introduced in GIMP 3.0.  It allows certain simple shapes, such as lines and circles, to be converted into vector objects.<ref>{{cite web |title=2021 Annual Report |url=https://www.gimp.org/news/2021/12/31/gimp-2021-annual-report/ |date=31 December 2021 |website=Gimp.org |access-date=15 February 2022 |archive-date=24 January 2022 |archive-url=https://web.archive.org/web/20220124161618/https://www.gimp.org/news/2021/12/31/gimp-2021-annual-report/ |url-status=live }}</ref><ref>{{cite web |url=https://ctx.graphics/ |title=ctx – 2d vector graphics stack |website=Ctx.graphics |access-date=15 February 2022 |archive-date=13 February 2022 |archive-url=https://web.archive.org/web/20220213002019/https://ctx.graphics/ |url-status=live }}</ref>

=== File formats ===
GIMP supports importing and exporting with a large number of different [[file format]]s.<ref>{{cite web |title=File formats supported by the GIMP |url=http://www.gimphelp.org/formats.shtml |date=2007 |website=GimpHelp.org |archive-url=https://web.archive.org/web/20090830034326/http://www.gimphelp.org/formats.shtml |archive-date=30 August 2009 |access-date=2 July 2009 }}</ref> GIMP's native format [[XCF (file format)|XCF]] is designed to store all information GIMP can contain about an image; XCF is named after the e''X''perimental ''C''omputing ''F''acility where GIMP was authored. Import and export capability can be extended to additional file formats by means of plug-ins. XCF file size is extended to more than 4&nbsp;GB since 2.9.6 and new stable tree 2.10.x.{{Citation needed|date=April 2023}}

{| class="wikitable"
|-
! style="width:12%;" | &nbsp;
! File formats
|-
! Import and export
| GIMP has import and export support for image formats such as [[BMP file format|BMP]], [[JPEG]], [[PNG]], [[GIF]], [[TIFF]]<ref>{{Cite web |title=GIMP - Feature Overview |url=https://www.gimp.org/features/ |website=Gimp.org |access-date=25 April 2024 }}</ref> and [[High Efficiency Image File Format|HEIF]],<ref>{{Cite web |last=Wilber |date=7 October 2020 |title=GIMP - GIMP 2.10.22 Released |url=https://www.gimp.org/news/2020/10/07/gimp-2-10-22-released/ |website=Gimp.org |access-date=25 April 2024 }}</ref> along with the file formats of several other applications such as [[Autodesk]] flic animations, Corel [[PaintShop Pro]] images, and Adobe Photoshop documents. Other formats with read/write support include [[PostScript]] documents, [[X Window System|X]] bitmap image, [[xwd]], and Zsoft [[PCX]]. GIMP can also read and write path information from [[SVG]] files and read/write [[ICO (file format)|ICO]] Windows icon files.
|-
! Import only
| GIMP can import Adobe [[PDF]] documents and the [[raw image format]]s used by many [[digital camera]]s, but cannot save to these formats. An open source plug-in, [[UFRaw]] (or community supported fork nUFRAW), adds full raw compatibility, and has been noted several times for being updated for new camera models more quickly than Adobe's UFRaw support.
|-
! Export only
| GIMP can export to [[Multiple-image Network Graphics|MNG]] layered image files (Linux version only) and [[HTML]] (as a table with colored cells), [[C (programming language)|C]] source code files (as an array) and [[ASCII art]] (using a plug-in to represent images with characters and punctuation making up images), though it cannot read these formats.
|}