Thursday, October 22, 2015

Digital painting in a nutshell

Revised on July 12, 2017

This is a quick overview of digital painting in six steps: what it is, what makes it different from non-digital painting, and what in my view are the main obstacles and challenges for artists and art lovers.
If you want to zoom in further, follow the link below.



1. Same process
Digital painters use a pen or stylo to paint on the screen of the computer, tablet or mobile phone. Mostly, they paint stroke-by-stroke. Just like a traditional painter, they can change brush tips, their brushes react to the pressure or movements of the hand, they can work in layers, and there is a color palette. The digital painting box is larger, but the act of painting is not different, and the creative process is exactly the same. 

2. New forms
Painting stroke-by-stroke with a digital brush in an ordinary painting program is called 'raster' painting. A digital painter can also use the power of the computer to construct shapes and forms. Think of a perfect circle, or a perfectly straight line. A human hand can't make these. If you order your computer to make a circle, it thinks of the mathematical formula of a circle, and this is what it will put on the virtual canvas. Any form or curve or patch of color can be captured by a formula. It can be changed and manipulated by the artist with the help of special tools, in a program for vector painting. This way, without having to do any mathematics themselves, the artist can create very regular vector shapes.




Pauline van de Ven: 'Ceci est un oeuf' 2015, 
vector and raster painting combined 


Often, raster and vector painting is combined in one painting. In 'Ceci est un oeuf' (above), the two upmost eggs and all the smaller forms in the image are vectors, constructed by formulas. You can easily recognize the hard edges, 'perfect' shadows, 3D illusion and smooth gradients. Only the lower left egg, a raster form, shows the imperfections and insecurities of a human hand.

3. Enlargement
Digital painters paint on the screen of a computer, on tablets, iPads and mobile phones. Their work is small in size. If it is to be brought into the real world, it will have to be enlarged. For vector paintings, this is never a problem. The computer quickly recalculates all the math that constructs the forms and neatly replaces them with larger ones. But raster is another matter! Try to blow up a newspaper photo: the more you enlarge it, the more empty space you will see between the pixels. The image will become blurred to the point where you won't even recognize it. Every raster painter has to solve this problem. Sometimes this is difficult or even impossible. Usually, it's just a lot of work.

4. Color
Color representation is the digital artist's main technical problem. It is very, very difficult to translate colors on the computer screen to the paper, canvas, polyester or whatever is used to bring a virtual painting into the real world. Color on a screen is always different from colors on non virtual carriers, if only because the computer has backlight. There are many more difficulties. It makes calibration of the computer screen a necessity for painters as well as for everybody who wishes to see a painting more or less as it was intended. There are many other things that the artist needs to do in order to obtain a satisfactory color representation. 

5. Uniqueness
To ensure uniqueness, the digital painter can use a certificate. Sometimes, the source file is transferred to the buyer as part of the sale. Or the file can be deleted altogether. Many artists and art lovers think that uniqueness is no longer possible or even desirable in the digital world.

6. Fusion and confusion
The relation between painting and photography is centuries old - but never before has it been so close. Painters and photographers now use the same toolbox. Photographers paint over photo's or automatically convert them to 'paintings'. Many painters do the same. Apps and programs offer a variety of standard filters to distort a photo and make it look like an aquarel, a linocut, an etching, in the style of Seurat, Van Gogh or Bacon - any painting technique in any style you like. The result can be printed or projected on canvas and painted over with real paint. Of course, photo's can be an expression of the heart and mind of an individual spirit, a reflection on life. They then stop to be a registration and become art. Naturally, whether a painting is or isn't a work of art, is not a question of technique, but it is worth noting that at this stage, only a handful of art professionals worldwide have the technical skills to distinguish what comes out of the app from what comes out of the artist.


Read more: A survey of digital painting






Sunday, April 19, 2015

A survey of digital painting


Everything the artist and collector should know about digital painting.

Definition
Visual characteristics
Separate carriers
Place of painting in digital art
Digital painting and photography
Computer generated art
Traditional digital painting
File formats
Size, resolution, enlargement
Correction of raster painting enlargement
About color
Transfer to physical carrier - brush strokes
Quality-quantity convention
Specific problems
Assessment, color and style
Market for digital art 
Registration
Certificates for originals and series
Links


Definition
A 'digital' painting is created on the computer using a graphics program, a virtual paintbox with brushes, colors and other supplies. The box contains instruments that do not exist outside the computer, and which give a digital artwork a different look and feel from an artwork that is made the traditional way. Once the design is finished, the painting is transmitted to paper, canvas, coated polyester, etc. Although this is not usually considered a painting, the design can also be displayed digitally or projected on a surface. 


Visual characteristics
Specific visual characteristics include: transparency, symmetry, distortion and exact repetition, perfect circles, squares and other shapes, embossing and other 3D illusion, and very fine, smooth gradients as well as perfectly monochromatic color planes. While it is not possible for a human hand to create exactly identical shapes, or construct a perfect circle or a perfectly straight line, for a computer it is difficult to do anything but that. Hence the typical occurrence of regular or 'vector' forms. These are usually not handpainted but chosen by form and size and manipulated with a special tool. What makes these forms different is that they are defined by a mathematical formula. The 'inhumanly' technical perfection of a vector based form is easily recognized. Most painting programs feature a number of ready-made vector shapes, like circles, ellipses, stars and squares. Both vector painting and combinations of vector and raster painting, or, to put it differently, both machine-driven mathematical perfection and combinations of mathematical perfection and typically human imperfection, create a language of color and form that is entirely new and cannot be expressed in traditional painting.
A further visual characteristic is the flatness of the physical representation, due to the technical impossibility to translate the brushstroke to surface texture.

Other characteristics
In many programs it is possible to undo many (or all) brush strokes or other actions without a trace, which permits a more spontaneous, intuitive way of working than is possible in traditional painting. The choice of program (or segment within a program) determines the output to look like a watercolor, screen-print, linoleum cut, oil painting, etc., — or combinations. In this respect, digital painting is not so much a new medium as the whole range of existing ones, supplemented with some new features.


Separate carriers
The creative process for digital and traditional painting is more or less the same, but when the digital artist is done, there is nothing to hang on a wall. The painting is on the hard disk of a computer. The usual way to make it presentable and sale-able is to project it on a traditional carrier, such as paper, canvas or polyester-coated photo paper. This is commonly done by a professional industrial printer. What happens to the digital carrier depends on how the artist wants to offer the painting. For an original, the digital carrier is either deleted or transferred to the buyer. For a series, the artist will delete the digital carrier when the prefixed number of copies has been reached. For an open ended series, the digital carrier will be retained on the computer. In all cases, the buyer must be informed about the status of the digital carrier.


Place of painting in digital art
Painting is one of at least five directions that can be distinguished in early digital art: (1) 'Computer generated art' springs directly from artificial intelligence and programming. The image is created in an indirect way, not by painting it but by instructing the computer how it should look. (2) 'Digital photo-art' starts with a photo which is manipulated and transformed into a new image with the help of digital tools; (3) 'Digital animation' is a series of paintings or drawings, not necessarily made on a computer, manipulated and put into motion with the help of a computer program. (4) 'Video art' likewise relies on manipulation of moving images. (5) 'Traditional digital painting' creates an image in a stroke-by-stroke, stylo-in-hand fashion, either with a fixed resolution (raster painting), or with a flexible resolution (vector painting).


Digital painting and photography
Over the centuries, artists have used a variety of tools to project reality on their canvas as raw material to be digested, translated, molded into their subjective interpretation of the outside world - including the camera. Digital painting makes a long standing practice much easier. Often, a photographer uses the same program for editing a photo as the artist for creating a painting. The shared toolbox creates a transition zone between photography and painting. The development is stimulated by programs that automatically convert photos into 'paintings', 'drawings' or 'cartoons', often with a choice of styles and palettes. (See link 'conversion' below).




Early digital art, computer generated
Computer generated art (code-mode): Lambert Meertens and Leo Geurts, Crystalstructuren, 1970



Computer generated art
'Computer generated' refers to the indirect method: the artist doesn't create the artwork by hand, but instructs a computer how to do it, similar to a composer creating music, not by playing it on an instrument, but by writing music notes on a score that are a prescription for how the music should sound.

  • Code-mode. The earliest of such prescriptions were given in code: the artist who wanted to create a black background, for instance, could do so by by writing, in a language that the computer could understand, something like: <body bgcolor="#000000">. Code-mode art offered a lot of freedom in style and idiom, but intricate forms were difficult to program. 
  • Design mode and fractal art. Modern painting programs enable the artists to construct images in the design mode ('what you see is what you get'). Knowledge of programming is no longer needed: images are created visually, on the screen. The codes that are needed for viewing, printing etc. are taken care of by the software without interference of the artist. It is still possible to create generated art. The artist selects a set of parameters and the software calculates and constructs the intended image. Programs for fractal art, for instance, aid the artist in constructing intricate forms based on a repetition of mathematical patterns. 


Traditional digital painting
Traditional digital painting is created in a stroke-by-stroke, stylo-in-hand fashion.

  • Raster painting. A raster, grid, or bitmap painting approximates most closely the traditional painting with brushes and paint. It is created free-hand, stroke by stroke. The colors are registered pixel by pixel on the virtual canvas and the resolution is fixed. As a result, raster files tend to be large and difficult to manage. Depending on the size and resolution of the image and the speed of the computer, the process of painting may become slow or even grind to a halt. Moreover, the artist will not be able to see the whole picture, unless zooming in and out frequently. In order to work swiftly and spontaneously, the digital carrier of a raster painting is therefore generally kept small, both in size and in resolution. Raster images made on mobile devices are usually as small in size as their screens. Some programs can export the images in a somewhat larger resolution to a painting program on a desktop computer (e.g., Eazel and Brushes to Photoshop), but even then, enlargement is necessary if a raster image is to be transferred to a physical carrier. Raster art is characterized by all the imperfections and vulnerabilities of handmade forms and lines.
  • Vector painting. A vector painting is usually created by making and manipulating lines and shapes with a special tool. The method requires some degree of determination and is less suitable for intuitive, spontaneous work. All lines and shapes of vector paintings are defined by geometrical formulas. As a result, their resolution is flexible and they can be enlarged to any size (within the vector program) without any deformation or loss of sharpness. Special tools not only help to create shapes, they can also translate handmade or scanned drawings into straight and curved line segments with coordinates that are captured in formulas. Thus formalized, the image can be subjected to mathematical operations such as enlargement or 3D rendering. Vector art has a characteristic, smooth, well-defined appearance, often with gradient colors, shades and 3-D shapes.

    'Ceci est un oeuf' (image below) illustrates the difference between vector and raster (bitmap) painting: all the shapes are vectors, with the exception of the lower left egg, that shows the characteristic imperfections of raster painting. If this picture is saved in a vector format (such as .svg) and enlarged, only the raster egg will pixelate and loose its shape. 

File formats
Common file formats for raster or bitmap painting: 
  • .jpg (Joint Photographic Group)
  • .gif (Graphics Interchange Format)
  • .tiff (Tagged Image File Format)
  • .bmp (Bitmap)
  • .png (Portable Network Grahpics)
Common file formats for vector paintings are: 
  • .svg (Scalable Vector Graphics); 
  • .eps (Encapsulated Postscript Format)
  • .ai (Adobe Illustrator) 
  • .wmf (Windows Meta File)
  • .emf (Enhanced Meta File)
Hybride file formats:
  • .pdf (Portable Document File) supports raster as well as vector painting. There are certain limitations for vector painting, however. 
  • .psd (Photoshop Document) will save a raster painting as raster and a vector painting as vector. 
Not all formats are compatible with different painting software. For example: while it is possible to make a vector painting in Photoshop and enlarge it within the program without loss of quality, you can't use Photoshop to open and edit a common .svg vector file. For a compatibility overview of vector file formats, painting programs and operating systems, see 'formats' in the links below.


Size, resolution, enlargement
As the artist increases the height and width of an image, its resolution, or information density, decreases and the raster imagine will become unsharp. Resolution is usually expressed in 'dpi' (dots per inch). While the digital carrier already looks sharp at the standard resolution of 72 dpi on the web, a physical carrier needs 150-200 dpi and is usually much larger in height and width as well. For a vector painting, where colors and lines can be controlled by formulas, resolution is flexible and enlargement requires nothing but a push on a button. To enlarge the lines and shapes of a raster painting, that cannot be captured by formulas, is a lot more difficult. Here, information has to be added to fill in the extra space. This is usually done in two steps. The first is a rough automatic interpolation of the image, either by specialized software or by a 'resize' option in the painting program. The second is a manual correction of the interpolation.


(Click to enlarge)

digital art, enlargement
Two enlarged fragments of Pierre Bonnard's Getting out of the bath (1930)

left: sawtooth edges, noise, and 'pixelated' color patches of enlargement by interpolation
right: hard, bold edges and deformed color patches of vector enlargement



Correction of raster painting enlargement
Much progress has been made in enlargement of raster images. Still, it remains difficult for a computer to stretch manual lines and shapes without loosing at least part of their determination and fluency. Lines become unsteady and crumbly, and unintended 'noise' appears along the edges of color patches. The image above shows two different types of automatic enlargement of the same fragment of Pierre Bonnard's 'Getting out of the bath'. We see part of Marthe's head and shoulder. It shows how each method entails its own noise and deformation. Usually, this is corrected manually. As a rule, enlargement of a raster painting needs correction, whether it is enlarged by vectorization or by interpolation. Although this is done in the post-creative phase, when slowness and incidental breakdown while working at large files is less troublesome, correction of raster images is often tedious and time consuming. There is a trade-off between the swiftness and ease of painting on a smaller virtual canvas, and the amount of non-creative energy that has to be devoted to correction afterwards. Other factors that influence the correction load of raster painting are the complexity of the image, the degree of magnification and the quality of the algorithms used for enlargement. Note that larger images that are to be viewed at greater distance may contain an increasing amount of 'noise' without this being disturbing or even visible.


About color
It is important to realize that it is highly unlikely that any color is reliably displayed on a computer screen all by itself. The same is true when the work is printed. In order to see and to show colors reliably, three things are needed: (1) the monitor should be calibrated, (2) the color profile should be embedded in the artwork, and (3) the artist should paint with the color palette that matches the destination of the artwork.
  • To see. For a reliable color representation it is absolutely necessary that the screen is calibrated. Some computers have the calibration software installed. Alternatively, external devices (see link color calibration below) are used to measure a number of colors on a screen and compare those with standard color values that are ​​set by convention. Both methods create an ICC monitor profile: a unique color profile that corrects the individual screen to the standard color values​​. The monitor profile can be seen as a pair of glasses that corrects the eye. It usually bears the name of the calibration software and is set as default profile for the monitor. The monitor profile does not go into the artwork, but into the settings of the computer.
  • To show. In order to ensure that colors of the artwork are faithfully represented by a printer or a browser, the artist needs to embed a color profile in the work. This ICC embedded profile can be seen as a key that artists, printers and browsers exchange in order to obtain a faithful color representation. The profile is chosen in the painting program and depends on how the artwork will be presented:

    - If it is to be printed on paper, canvas, etc., a CMYK profile is embedded. There are many CMYK color profiles, all with the same purpose: to ensure correct treatment of the colors by specific machinery, ink type, paper, coating, etc. that is used by the printing company. The printer should prescribe or supply this profile. If the printer can not specify a profile, FOTOGRA27 can be used, but it is better to work with a printer who works with a profile.

    - For display on the Internet, the artist embeds the standard RGB profile. The sRGB space is much larger than the color space for printing and it is important to know that most of the colors will be interpreted by browsers and apps. Inconsistencies occur. A hard core of 216 colors is fixed between browsers, regardless of the platform. If  color deviation is to be avoided as much as possible, the artist embeds the sRGB profile and paints in the websafe palette (see below).

    Even then, differences occur.  The image below was created in the RGB palette and spectrum, with the standard RGB profile embedded. In both cases, the screenshot includes part of the background color of this blog, color #333333. Since this is a web-safe color, no border should be visible. This is the case in the image left, displayed in Safari, but the image on the right, in Firefox, shows a border. It turns out to be color #2b2b2b, which can only mean that Firefox has changed a web-safe color. The border is also darker to the left and lighter to the right: the screen print reveals irregularity in the backlight of the monitor.
  • Palette, spectrum. The basic profile types, such as CMYK and RGB, have their associated palettes and matching color spectrum in the artist's workspace. It is necessary to work in the palette and the spectrum that matches the application - CYMK for printing in color, RGB for display on the Internet, and grayscale for black and white.

      
About colors

Pauline van de Ven: 'Winds of change' (2015)
Color differences in online display. Left: Safari. Right: Firefox.



Transfer to physical carrier — brush strokes
The transfer is usually executed industrially. Popular physical carriers are paper, perspex, wood, porcelain, canvas, aluminum and polyester. In digital painting, brush strokes are an illusion. The projection of the artwork will be entirely flat. Over many centuries, art lovers have felt the hand and the mood of the painter reflected in brushstrokes on the canvas. Many artists as well, find the look and feel of a texture-free canvas somewhat 'fake'. There are several ways to go about it. Some artists apply layers of a clear acrylic glazing gel to the physical carrier to recreate the brushstroke and add texture to the projection (see 'brushstroke gel' below). Others succeed in creating a convincing illusion of texture, or they use flatness to their advantage and choose the light, elementary carriers that have been developed for photography.

Quality-quantity convention, limited editions
In traditional painting, the numbering of a limited edition by convention follows a quality/quantity notation 'x/N' in front of the artwork. The 'x' indicates a rough ranking of the print according to technical and aesthetic quality (highest for x=1), while 'N' represents the (intended) edition. Since all limited prints of a digital artwork are identical, the meaning of x has primarily become an indication of scarcity. Prices sometimes reflect this, by being low at the opening and higher towards the closing of the edition.
The quantitative information of 'N' is the same as in traditional painting and has economic significance for buyers and dealers. Following standard practice, the digital artist (or his representing gallery) determines a series to be 'open' or 'limited' prior to sale, and keeps register of the number of sold copies of a limited edition. Open series are referred to as 'x/X, and originals sometimes as '1/1'. In the generally outsourced, industrial printing process of digital painting, the unnumbered specimens and misprints of the manual printing process, referred to as 'E.A.' (epreuve artiste) or 'A.P.' (artist's proof), are rare, and mostly about misrepresentation of colors.


Specific problems
Working with two separate carriers — the hard disk where the painting was created and saved as a file, and the paper,  canvas, polyester, etc. on which it is projected, and which becomes its actual physical appearance — raises some specific difficulties:

  • Uniqueness. How to protect the numerical uniqueness of an artwork if the source is stored in singe digits in the computer? (Secure delete, safe transport, professional printer, certification). A 100 pct. vector painting can not be protected. 
  • Color. There is little consistency across desktop, laptop, and mobile devices. Different computer screens present the same image in different colors. Monitors also change over time. Prints often do not match the colors on the computer screen. Browsers, programs and apps interpret the same colors differently. (Calibration, color profiles).
  • Enlargement. A problem for raster images is, how to sufficiently increase the length and width dimensions of the artwork to make it presentable and salable, without distorting lines and forms and without the file becoming unmanageable. 
  • Copyright, self-expression. A problem of a different nature stems from the relative ease to copy-and-paste in the digital working space, which occasionally raises questions about copyright, and about to what extent the artwork is a form of self-expression.
  • Assessment, see below.

Assessment
The technical quality, resolution and technique of a digital artwork can be assessed online in a 1:1 detail. Other aspects of assessment are color and style. A recent development is that a prospective buyer can ask for a sample before buying (depending on the carrier).

  • Color. For a faithful representation of colors, it is absolutely necessary to calibrate the computer screen (see links below). Due to the backlight of the computer screen, which adds clarity to the image, the online presentation will always differ to some degree from the artwork on its physical carrier. It is a good idea to look at the artwork in different browsers.  
  • Style. The array of painting apps makes it an area of sound (but still scarce) expertise to distinguish the style of the artist from the style of the software. Ben Guerette's 'A Blog appArt' (link below) gives insight into a wild variety of styles that are nothing but an attribute of the software. A professional artist will develop a personal style in interaction with the style of the software and the style of the software will always be present in the artwork, but a collector needs to know which is which. Since the introduction of programs that convert photos to paintings, a similar difficulty arises in distinguishing registrative from creative art. Because conversions create regularity, combinations of photo-like representation with regularity in brushstroke and color, this is what the expert will probably want to avoid. A different approach is: if the eye likes it, the technique doesn't matter.



Market for digital art
The market for digital art is slowly maturing. Collectors are beginning to see that digital panting is a new visual language, with characteristics that could never be realized with traditional means. The first online auction, by the UK auction house Phillips in cooperation with Padle8, took place in 2013. There are several large online galleries where both originals and prints of digital paintings are shipped worldwide with good sales conditions, AbsoluteArts and Saatchi being the most popular. Technical problems have largely been solved: screens are calibrated. Artists and printers work with color profiles. Color representation can be fairly reliable, both online and in physical representation. Originals are hand-signed. Certificates are used to distinguish between original artworks and series, and to specify the number of copies of a series. As to the risks of duplication, online display of artworks is carefully kept at low resolution and low size, artists make use of safe online transport to professional printers, and original artworks are securely deleted after sale. The risk of duplication can never be excluded, but with standard precautions can be kept acceptably small. It should be noted that vector paintings are the only exception. Even if displayed in a non-vector file format, such as jpg, and kept small in size, and low in resolution, the inherent regularity of forms and colors in vector paintings make that they can be re-converted without loss of information to a vector format clone.

Concerning the risk of duplication, one may realize that the difference with traditional art is not so much in the risk itself, as in the ease and the cost. Modern techniques for projection and color measurement make it possible to order an accurate hand painted copy of any traditional painting (see 'hand painted copies' in the links below). 'Real' paints, inks, etching grounds, etc. no longer protect an original artwork as well as they used to do.

If we conclude that technical problems have 'largely been solved', this does not mean that the above standard has already been adopted by a majority of digital artists. This will probably take several more years. The current situation is that many highly professional, even pioneering digital painters still have no idea how to get their work out of the computer and up on a wall. Most rely on the online gallery to offer quality prints of their work. These are open or limited editions. Originals, by contrast, require a signature by hand. This means that the artist himself has to make the transfer from digital file to physical representation, so high quality originals are rare. With growing technical skills and knowledge however, more original artwork will probably be offered.

One major problem left to be solved is that traditional galleries are not yet very interested in digital painting. It is very difficult for artists to find representation and to exhibit their work in the 'real', non-virtual, art world. As a result, digital artists have to offer their work directly, through online galleries or places like eBay. They also participate in the - few and costly - juried international exhibitions that take over the selection process traditionally done by galleries. Against this background, prices of digital artwork are low.


Registration
So far (2015), registration is only offered for artwork on Hahnemühle paper (see link 'registration' below). In the mean time, artists and collectors may want to keep trace of respective owners by certificates.


Certificates for originals and series
Certificates stimulate the development of a clear and trustworthy formula for the selling and buying of digital art. They include the statement of the artist that he or she is the only creator, distinguish between an original and a series, specify the edition of closed series, bind the artist to secure deletion of originals and closed series, and condition the use of 'display copies' by the artist after the sale - and much more. A Standard Certificate of Unicity (SCU) for originals, and an SC for series is regularly updated and freely available on this site.



© Pauline van de Ven, March 2013-August 2015


Computer generated art
Computer generated art (code-mode): Peter Struyken, 1970




Computer generated art, fractal
Computer generated art (design-mode), fractal-art: Karin Kuhlmann, In between 11 (2008)



Digital photo art
Digital photo-art: Dolores Kaufman, Inner sanctum  (undated)


Vector art with a raster shape: Pauline van de Ven, Ceci est un oeuf (2015) 



digital video art
Digital video art: Alessandro Bavari, Metachaos (start) (1994-99)



digital animation art
Digital animation art: Dudok de Wit, The arome of Tea (start) (2006)



digital art, traditional
Traditional digital art: Ivan Gontsharov Seven days - Friday (2011)



digital art, mixed techniques
Mixed techniques, digitally manipulated wall painting: Lev Stepanos, untitled (undated ±  2012)


LINKS (abc):

Brushstroke gel: 
Blogs:

Calibration of colors: 
Carriers for digital painting:
  • Polyester coated paper: Xpozer http://xpozer.com (RGB,  color-true to calibrated screen, mounted/stretched by aluminum in the back for unframed display, design award)
  • Paper: local printer for large format prints on German etching paper etc.
  • Canvas: http://www.kunstkopie.nl
  • Manual enlargement from a small to a large physical carrier (tracer): https://www.artograph.com
Conversion:
Enlargement:
Formats, vector:
Fractal art: 
Galleries, digital:
Galleries, physical:
Hand painted copies: 
Museum for computer art MOCA
  • http://moca.virtual.museum The Museum of Computer Art (MOCA) of New York State University offers emerging directions in digital art an online platform since 1993. Annual competition in digital art, catalogues.
Photo art: 
Programs for animation painting:
Programs for painting on iPad and iPhone:
Programs for painting on PC and Mac:
Programs for fractal painting: 
Programs for vector painting:
Registration:
Style:
  • Ben Guerette, A Blog appArt  (Extensive survey of styles and features of painting software) 
Vector art: 
Vectorization, online (raster to vector conversion):


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