Rebelle (software)

Rebelle is a raster graphics editor for digital painting and drawing, designed to simulate oils, acrylics, watercolors, pencils and other traditional paint media on a digital canvas. It is developed and published by the Slovak company Escape Motions. The software is intended to be used by everyone interested in digital painting, from children to professional digital painters, concept artists and illustrators. It was first released in 2015 and has since gained popularity among artists seeking to replicate the natural and organic feel of traditional tools in a digital environment.

Rebelle’s paint engine simulates various types of wet and dry media. The pigment color mixing, oil thickness, watercolor diffusion, and NanoPixel technology work together to realistically emulate how natural media interact with each other and with the canvas.

The first Rebelle version was released in 2015. Escape Motions was accepted to present it at the SIGGRAPH’s 2016 Appy Hour where independent app developers introduce their apps to the attendees.

The current version is Rebelle 7, released in December 2023. Rebelle is currently available in two different editions: Standard and Pro which includes additional features: Pigment color mixing, NanoPixel technology, Metallic materials, Photoshop plugin, Color management, and Fractal image resizing.

Rebelle is compatible with Windows and MacOS and is designed to be used with a tablet PC or graphics tablet, but it can be used with a computer mouse as well.

Tools and Features
Rebelle includes wet media tools: oils, acrylics, watercolors, ink pens, and dry tools: pastels, pencils, charcoals, markers, and airbrushes. Other tools are blend, smudge, liquify, clone, fill, water, dry, blow, color picker, tilt, transform tools, selection tools, and more.

Rebelle includes different types of customizable brushes with various brush textures. It offers multiple paper surfaces, that serve as a background for the painting and dynamically interact with the painting tools. The software has a touch gesture system for touch and multitouch displays which supports simultaneous zooming, rotating, and panning.

Watercolor and wet media simulation, DropEngine
Rebelle’s watercolor simulation is built upon real-world color mixing, blending, moistening, and drying. The fluid simulation is based on Navier-Stokes equations to simulate the realistic fluid flow occurring in nature. Watercolor simulation in Rebelle is an extensive sandbox that consists internally of multiple layers, used to calculate the water and paint simulation, wetting, drying, and re-wetting already dried colors. Users can paint, erase, blend, and smear the painting, tilt the canvas to create water drops, and various watercolor effects, which are calculated in real-time. The simulation offers a realistic granulation effect as the paint dries into the paper.

Thick paint and impasto
Rebelle supports laying down thick layers of paint and lets users control the impasto depth of oils and acrylics. Creating thick or thin layers is possible with the Impasto engine which uses a height map of the painting's structure.

Pigment color mixing
Rebelle 5 released in December 2021 introduced physical color mixing based on traditional pigments. It produces saturated gradients with hue shifts and natural secondary colors during blending. As a result of this colors mixing model, colors mix realistically, e.g. yellow and blue colors make green color. The implementation is based on the Mixbox model developed by Secret Weapons. Their paper Practical Pigment Mixing for Digital Painting developed a mixing approach that rectifies the behavior of colors by leveraging the Kubelka–Munk model and was accepted for Siggraph talk in 2021.

NanoPixel
Rebelle 5 Pro introduced technology for resizing paintings and canvases in real time called NanoPixel. The technology is based on machine-learning algorithms, especially deep learning and it allows exporting 16x larger paintings. NanoPixel depends on GPU power and OpenGL for rendering the painting.

Fractal image processing
Rebelle 6 Pro released in December 2022 brings the image recognition machine learning algorithm for keeping the image quality and sharp details when using the Warp and Liquify tools, transforming and deforming layers or objects on the canvas.

Metallic materials
Rebelle 7 Pro features Metallic materials. They work with the Oil & Acrylics tool, making it possible to mimic the look of real-world metallic paints. Users can control the look of materials with various settings.

Photoshop plugin
Rebelle Pro offers a Photoshop plugin called Escape Motions Connect. It is a JSX file that can be installed into Photoshop as a panel and allows the exporting of layers between Rebelle and Photoshop. The plugin is compatible with Photoshop CC 2015 and newer.

Papers and art surfaces
Rebelle introduced a new approach to how the background in digital painting software reacts to the paint by developing art surfaces based on real-world papers. This includes hot-pressed, cold-pressed, rough papers, canvases, washi, handmade, and watercolor papers of all kinds that can influence how the paint reacts to the surface. Version 7 featured rendering based on ray tracing which made it possible for the paint to react to the actual bumps and irregular heights of the paper textures.

Versions
The current version is Rebelle 7 and is available in two editions: Rebelle standard and Rebelle Pro which includes everything from standard edition plus additional Pro features: Pigments color mixing, NanoPixel technology, Metallic materials, Photoshop plugin, Color management and Fractal image resizing.

Free trial version
You can test a 30-day free trial version which is available on the developer’s website.

Version history
Rebelle has undergone several iterations since its initial release, with each version introducing new features and improvements.

Rebelle Beta 0.5.0 - 0.8.6
Rebelle desktop application was released for pre-purchase as a public beta in April 2015 for Windows and macOS and included notable features: watercolor simulation, painting tools (paint brush, wet brush, dry brush, smear brush, blend brush, tilt canvas), color palettes with custom colors and color picker, various paper textures, 23 layer blending modes, and tablet support.

Rebelle 1.0
The first version was released in May 2015 and expanded on its beta predecessors with image import, transform layer tool, and image tracing.

Rebelle 2.0
The second major release was launched on April 25th, 2017 and introduced a new brush engine, custom brushes, stencils and masking fluid, selection tools, layered PSD support, and support for multi-touch gestures.

Rebelle 3.0
Rebelle 3 was released on May 1st, 2018 and featured realistic papers, redesign of the watercolor simulation code, DropEngine, "Masking Fluid" layer, Straight line, Ruler, Perspective tools, "Reference Image", and "Preview" panel.

Rebelle 4.0
Rebelle 4 version was released on December 16th, 2020 and introduced Oils, revised Watercolors and watercolor simulation, wet & dry media mixing, performance optimizations, color management, layer groups, clone and fill tool, support for pen tilt, brush line stabilization and improved Brush Creator.

Rebelle 5.0
Rebelle 5 was released on December 16th, 2021 and introduced two editions - the standard which brought tools like multicolored & dirty brush, express oils, volume presets & curve editors, color Mixing Palette, time-lapse recording and full-color papers and Pro edition that in addition offered Pigments color mixing, NanoPixel technology and Photoshop plug-in.

Rebelle 6.0
Rebelle 6 was launched on December 15th, 2022 and included a lot of new tools such as liquify and warp tools, clipping and layer masks, grid & guides, reference image guides, favorite brushes, stroke length slider, upgraded brush creator, improved pencils and pastels, new image filters and color range, light and dark interface theme. The Pro edition featured Fractal Image Processing for Transform, Liquify and Canvas Size tools for keeping the best quality for image transformations and deformations using a machine-learning algorithm.

Rebelle 7.0
Rebelle 7 was released on December 14th, 2023. It included new features: Metallic materials, improved paper and art surfaces, structures, paths, gradients, or Filter layers. Rebelle 7 becomes natively compatible with Apple M chips.

System requirements
Rebelle has full 64-bit support on Windows and MacOS.

Minimum system requirements are Intel i5 or equivalent AMD processor, 4 GB RAM, 1,5 GB hard disk space, a graphics card with 1 GB RAM (OpenGL 3.3 required for Rebelle Pro), Windows 10 (64-bit) or Mac OS X 10.15.

Recommended system requirements are Intel i7 (6th gen or newer), equivalent AMD processor, or Apple Silicon (M-series) chip, 16 GB RAM, 1,5 GB hard disk space, a graphics card with 2 GB RAM: NVIDIA gtx760 for FullHD, NVIDIA gtx1060 for 4K screen, or equivalent graphics card, Windows 10 (64-bit) or Mac OS 11 and newer.

Supported file types
The native format is .REB which keeps all information about the layers and settings. Images can be exported to the following formats: PNG, JPEG, BMP, TIFF, WebP and Adobe Photoshop's PSD format.

Reception
Rebelle has garnered praise from artists and critics alike for its realistic simulation of traditional painting techniques. Its ability to mimic the behavior of oil, watercolor and other media has earned it a reputation as one of the leading digital painting software options for artists. Creative Bloq named Rebelle as the best affordable painting software. TechRadar included Rebelle on the list of the best digital art and drawing software of 2024. The software has been used by professional artists and hobbyists alike to create a wide range of artwork, from illustrations and concept art to fine art pieces.

Escape Motions
Escape Motions is a Slovak-based software development company specializing in graphics software for artists of all levels.

Escape Motions developed other graphics software: Flame Painter for painting with particle brushes, Amberlight for creating abstract art and animations, and Inspirit for creating mandalas. The software is compatible with Windows and macOS, Flame Painter and Inspirit were also developed as standalone apps for the iOS platform.