The Digital Illustration Edge

When it comes to creating illustrated imagery, one type of element that is important in every illustration, and is often taken for granted is an edge. In the non-digital illustration world edges are created by the physical use of an art material, but in the digital world, edges must be created in a virtual way to simulate a non-digital visual appearance. Image software programs like Adobe Photoshop provide both automated and user defined ways to manipulate an edge. So, as is the case with every aspect of a digital image, the illustrator has the ability to influence the look of edges in their work. It’s helpful to know how digital edges are rendered and displayed.

Anti-Aliasing

A good explanation of anti-aliasing begins with a good description of display aliasing. Basically, aliasing is a jagged or stair-step appearance that is caused by a lack of resolution either by restrictions in a hardware device, such as a display, or file size limitations in a raster-based document. Anti-aliasing is the technique software designers have adapted to reduce or eliminate jagged edges by fooling the eye of the viewer. This is done by creating a diminishing series of shading steps between the edges of adjacent colors. See Below. Anti-aliasing is also referred to as “smoothing”.

Closeup of aliased stair step in red, anti-aliased smoothing in blue.

Aliased mountain rendering. © 2012 Don Arday.

Anti-aliased mountain rendering. © 2012 Don Arday.

Closeup of the anti-aliased edge of a rose petal.

Interpolation

Anti-aliasing occurs through the interpolation of picture elements, “pixels”. Think of interpolation as swapping and sharing. To improve the digital visual appearance of an image on our monitor the technique of interpolation is used. Let’s refer to the data in an image as a sample. To make the image display better, the computer converts the image to a higher sample by using filtering techniques like anti-aliasing. It may be no coincidence that the word interpolation bears a resemblance to interpretation, because that is sort of what occurs within anti-aliasing. The software in the case of a document, or the computer video card in the case of the display, interprets the color relationships when attempting to create a smooth transition between one color and another to render edge pixels. This generally occurs automatically, but illustrators can use manual methods to control the appearance of edges within their illustrations.

Dithering

Dithering is often confused with anti-aliasing, but it is actually something quite different. Dithering most often occurs in color image situations where colors in an image are out of the range of the colors available in an image display or output device. When this occurs the software program creates the unavailable color by mixing other colors that are available. For example, dithering can occurs when a particular web browser does not support a specified color. The browser will then attempt to mix the requested color by “dithering” pixels by using a combination of other colors it can produce.  Although usually invisible to the naked eye, dithering is done in the same manner as “noise” is, (see below) and like noise, it can appear slightly grainy in the extreme.

Some Manual Techniques

Feathering

Feathering is the softening of edges of adjacent shapes and colors within an image beyond the standard level of interpolation. Adobe Photoshop gives you the option to feathering selection edges in an image. A feathered edge results in increased edge blurring and a lowering of edge contrast between colors. With feathering, the artist has the ability to control the number of pixels to be included in a feathered edge. The result of feathering is similar to that of Gaussian blur. (See below.)

Gaussian Blur

Using Gaussian blur, or any of the other blur options in raster programs, means to force adjacent colors to drift into one and other creating a smoother edge transition. Colors in a Gaussian blur drift in a randomly distributed, non-linear manner. A motion blur option of the Gaussian blur limits the random color distribution to a particular direction. Blur can be used to redefine edges, and it can also be used to control the amount of focus in an image.

Gaussian blur applied to complimentary colors.

Gaussian blur closeup.

Noise

Although a controllable option in Photoshop, and a very useful one, noise, and specifically random pixel noise is not necessarily thought of a s a good thing. Pixel noise is an unnatural, or unwanted, variation of value or color information in an image. Noise has a tendency to degrade sharp edges within an image by producing a scattered effect of random colored pixels. So a yellow flower against a blue sky may end up with blue pixels mixed among the yellow ones. And the flower and the blue sky might both have red pixels scattered in as well. See below. Photographers generally find noise to be very disturbing, however for the illustrator it may help to produce a desired, even naturalistic color effect. Noise is best applied as a final stage before publishing an illustration. And once saved an illustration that has had noise added is permanently altered, so it is always best to save your illustration prior to using noise, then save the noise applied version as a separate file.

Noise applied. Note the addition of other color pixels to the original pair
of complimentary colors.

Noise closeup.

Sharpening

The three techniques discussed above can produce a smoothing appearance to an edge, but they also degrade its sharpness. Using a sharpening filter or “Unsharp Mask” in Photoshop can give the appearance of actually sharpening edges. Sharpen filters identify where dark and light edges meet in an image, and add contrast to those edges. The filter does this by creating an even darker line along the edge of a dark shape, and also a lighter line on the edge of an adjacent light shape. Unsharp Mask tends to move edges away from an anti-aliased appearance, and taken to far, sharpening can produce a very unnatural looking halo around shapes. See below. Sharpening like noise is best applied as a final stage before publishing an illustration.

Edge sharpening applied. Note the increased contrast at the edges of
the two colors.

Edge sharpening closeup.

There are also some techniques in Photoshop for working with edges that rely on methods of selection like “Refine Edge” and “Fringe”, but the result of any of those actions uses the above basic methods of rendering.

By understanding how digital image edges are rendered and by using these manual options for refining them, you will have greater control over the appearance of your illustration either in print or on the monitor.

Archival Digital Art

“I’m a digital artist. All the images I have made in recent years are ‘virtual’".

I remember when photographic film manufacturers used the word “archival” when describing color film and prints. In the 1980’s and early 1990’s, after a quarter of a century the images many of us documented our lives with began fading beyond recognition. And the highly prized photographic work of renowned artists and photographers was in danger of becoming worthless. About the time color chemically produced prints began to show signs of degradation, digital printing devices began to hit the market. Although originally developed as proof printing devises for the printing industry, inkjet color laserwriters, and dye sublimation printers showed promise to be the saviors of artistic and photographic image printing. In the early 1990’s, with little concern about the composition of inks and the rag content of paper used by the printer manufacturers, digital printers could only hope for the same shelf life as the emulsion sensitized color prints that preceded them.

Digital Data Lifespan

It is highly advisable to store important images and digital information using multiple sources and to periodically transfer the data from old archive storage to new storage. Top manufacturers like Mitsui, Verbatim, Maxell, Memorex and TDK claim that premium compact discs, with protective coating and special dyes, will last from 50 to 200 years for CD-R’s and somewhat less for CD-RW’s, although I’ve had disks become unreadable after about ten years. Third generation flash memory is estimated to have a lifespan rating that is based on the number of erase/write cycles instead of a time span. The maximum number is approximately from 10,000 for multi-level cell (MLC) memory to 300,000 writes for single level cell (SLC) memory. The type used on the MacBook Air and the iPad is MLC. Magnetic platter hard drives, the drives in most computers, are estimated to last from 3 to 7 years, however treated well many drives that last longer than that. I recently booted up a hard drive that I mothballed in 1995.

It is also highly advisable to periodically open up older files in new updated versions of software and resave them. Regarding that data on that drive from 1995, I copied it and transferred it to my new Mac, which runs current versions of Adobe and Microsoft software. I found there were files that were simply too old to be recognized by current software. Know that the concept of universal upward compatibility was not always around, nor will it necessarily be around in the future.

“Never trust the technology. Always be prepared for the unexpected.”

Digital Prints

There are two factors that determine whether digital prints are archival, the paper and the ink. Through testing projections, manufacturers try to predict the future permanence of their products. As digital image makers we rely on these products and those predictions.

For several years I have used an Epson Stylus Photo R1900 printer, which uses Epson UltraChrome Hi-Gloss pigmented ink with clear “gloss-optimizer”. It’s a 7 color pigmented inkjet system. I print on Epson Watercolor Paper Radiant White Matte coated fine art paper, as well as a number of different kinds of fine art 100% cotton rag papers. Wilhelm Imaging Research, Inc. rates the above combination with the Epson paper to have an archival longevity of 200 to 300 years.  Resource: http://www.wilhelm-research.com/epson/R1900.html

“A digital print gives digital work a physical legacy and form of permanence”.

The Paper

100% rag cotton fiber rag quality paper is estimated to remain stable for between 250 to 300 years. Seizing on an opportunity, paper manufacturers with hundreds of years of experience in making archival papers for the fine arts, decided to renovate their tried and true paper formulas for digital printing. Canson, who makes a variety of digital papers including BFK Rives and Arches, was founded in 1557. Both of those 100% rag papers are available for digital printing. Since 1584, Hahnemühle has been making superbly crafted, unique, beautiful papers. Their papers are available for digital output. Crane & Company, which began in the mid 18th century, the same company that supplies the paper used for US currency, makes the Museo line of papers for digital printing. These papers are acid free with 100% rag content. So some of the finest papers for digital printing are available for our use.

The Inks

Ink color changes over time. The change can appear as a lightened washed out look or a flattening of brightness and contrast. Early producers of inkjet prints were astounded to discover that their prints faded within months. The environmental factors contributing to fading are light, temperature, humidity, etc. Museums and galleries place tremendous importance on carefully controlling light levels and humidity. With a digital print, the ink itself, the type of color dyes or pigments used, can also contribute to a lack of color stability.

Dyes

Printing inks now come in two main forms, as dyes or as pigments. Just a few years ago, all inks for inkjet printers were dye based. Dyes make very rich colored prints but are susceptible to fading. Ink manufacturers have also developed archival dye-based inks that are now available. Archival dye inks are less expensive than pigment inks. Some are very hardwearing and appropriate for the needs of most consumers. If well taken care of, prints may last for several generations.

Pigments

Over the past few years, ink manufacturers have made significant advances in combating fading by introducing pigment-based inks. Pigments are much more resistant to fading than dyes. Pigment is permanently colorfast, stable, and enduring, making it the superior choice for archival material. Archival pigment-based inks are more costly than dye-based inks. Governments print important documents with pigment-based inks to preserve them for the future.

In Conclusion

The future may hold changes such as the addition of new file formatting options and the elimination of old ones. SCSI and PS2 cables have become history. Will USB, Firewire and other computer connectors also become obsolete? Because of this, it is important to establish a system for archiving and preserving your digital work, and to consider transitioning through changes in hardware equipment along with advances in software technology.

Choosing Inkjet Paper: On the Surface

This post is a follow up to a former post titled Inkjet Paper Grain: The Long and the Short of It.

There is a lot of information about inkjet papers with regard to their use for printing photographs, but there is relatively little when it comes to digitally printing illustrations and art. The factors for illustrations vary from photographic subjects when choosing a type of inkjet paper for digital printing. Whether you created your illustration digitally or are reproducing it from traditional media, the following considerations will apply. There are practical concerns, such as: Is the paper affordable? Will it work for the needs of the project? And is it the right type of paper for my printer? There are also aesthetic considerations like: Is it the right paper surface? Is the paper color the right base tone for my illustration? And is it the best texture for my subject?

Aesthetic Considerations

The first thing to consider when it comes to the aesthetics of a digitally printed illustration is the illustration itself. The style it was rendered in, media, and subject matter play the most important roles when determining the choice of paper. Choosing paper stocks can be quite easy when you consider style and subject. Although it wasn’t always this way in the past, there are literally hundreds of quality digital printing paper stocks to choose from. Here are some general suggestions to help in making choices.

Media Factors

Consider the look of the media or technique that was used predominantly in your illustration. If traditionally produced, what materials were used, oils, acrylics, pastels, pencils, etc.? Was there varnishes or fixatives applied to the illustration? What canvas or paper surface was used in the original? If digitally produced what materials were simulated? Each material used displays a different look to the surface finish. One suggestion is to look for a type of paper that will present a similar look to its surface when your illustration is printed. An example would be to choose a less absorbent paper to reproduce a varnished oil painting on canvas, so the ink will set up on the surface and display more sheen to compliment the sheen of the original painting. Although an outright “gloss” surface paper may not be appropriate because of its surface distractions, a less absorbent smoother surface inkjet paper, will also allow the natural surface of the original to be seen if the digital file, scan, or photo contains that information.

Something to watch out for is choosing a paper surface that mimics the paper or canvas surface of an original. For instance, a watercolor painted on a cold press paper, can produce a disquieting textural effect when printed on a digital paper with a pseudo watercolor textured surface. Printing on inkjet canvas stock can enrich digital illustrations that simulate thick pigment oils or acrylics where thickly applied paint has completely covered the original canvas texture. The inkjet canvas stock then replaces the original canvas without conflicting with it texturally.

For pastels and other types of media that produce a matte surface, more absorbent smooth or matte surface inkjet papers may be most appropriate.

Color pallet also comes into play as well. Illustrations that use brighter more primary based color schemes generally work better on inkjet paper surfaces that are classified as “brilliant white”. Illustrations that have more earthy tones or naturally generally look superior when printed on “neutral “ surface papers, also called “naturals”.  Since wood and cotton fiber are off white in their natural state, brilliant white or bright white papers contain a high degree of “brighteners” to reveal their blue-white color. Neutrals generally do not contain brighteners.

Subject Considerations

The subject of an illustration can provide the answer to which inkjet paper to use. For instance natural landscapes with warm tones appear to remain natural when printed on natural finish papers. Human subjects also appear more natural on these off white or natural white paper stocks. Conversely, aquatic subjects, depending on the settings, may look better printed on a brilliant white paper with its blue cast.

Paper surface is also a factor. Subjects with a lot of texture such as mountains, stones, trees, sand, soil, etc., may look better on a granularly textured surface paper such as a satin, pearl, or luster. An excellent example where the subject might overrule the media factor would be a highly realistic digital, or a traditional acrylic painted illustration of an automobile or motorcycle working best when printed on a glossy surface.

Cost Factors

Inkjet papers vary widely in price, specifications, and even sometimes availability. For instance at the time of this post, Aurora Smooth available from Red River Paper Company was available for $1.06 per 13” x 19” sheet, while Canson BFK Rives was available for $4.28 per 13” x 19” sheet, and Crane Museo Silver Rag was available for $5.28 per 13” x 19” sheet.

Usage Factor

The requirement of the project is another consideration that goes into choosing an inkjet paper stock. The weight of the paper and whether the sheet needs to be long grain or short grain will influence the paper choice. For instance, not all inkjet papers are available in the short grain format.

Printer Limitations

The limitations of the printer are also a consideration. Some printers are limited to certain paperweights. Others are hampered by a very limited number of print preparation commands. For example, most printers do not have a paper surface option for printing on a velvet surface paper programmed into the printer media selections.

Paper Finishes

Paper finishes are classified using the following terms, gloss, semi-gloss, luster, satin, silk, pearl, velvet, canvas, watercolor, matte, and smooth, among others. The important thing to remember regarding the classifications is there are no industry set standards. One paper manufacturer's velvet might be much more coarsely textured than another manufacturers. Rather than try to provide a definition of the paper surfaces mentioned above, I recommend reading the descriptions provided by the manufacturers for their paper stocks. Here are a few links to some of the major inkjet paper companies.

http://www.epson.com

http://www.hp.com

http://www.hahnemuehle.com

http://www.innovaart.com

http://www.canson-infinity.com

http://www.crane.com

http://www.moabpaper.com

http://www.redriverpaper.com

http://www.ilford.com

http://www.fredrixprintcanvas.com

http://www.inkpresspaper.com

http://www.legionpaper.com

Conclusion

In the end, as always, the aesthetic choice is a personal one, and common suggestions and guidelines may not be all that useful. I can serve as my own example for going against the trend. Much of my work is based on hard geometric shapes, however by pairing my images with the unlikely choice of a watercolor textured inkjet paper, I achieved very aesthetically pleasing results. If you have the resources and inclination, I encourage you to try different paper stocks to find the ones that most please you. 

Inkjet Paper: The Long and the Short of It

Fiber

Paper is made up of fibers that come from various materials.  Different types of fiber material produce different kinds of grain structures. Wood and cotton are the most common types of fiber used in commercial inkjet papers. Wood when broken down generally produces shorter fibers, while cotton forms longer fibers.

Some paper companies market specialty papers made with other forms of fibrous materials. The Hahnemühle Paper Company makes alternative fiber inkjet printer papers such as rice, bamboo, and sugar cane papers.

Grain

The term “grain’ in reference to paper refers to the direction fibers are oriented that make up a sheet, or “grain direction”. When paper is manufactured, the fibers become oriented in parallel to form the paper grain. Paper sheets are referred to as being either long grain or short grain. This should not to be confused with papers having long or short fibers. Fiber makeup and grain structure are distinctly different. One refers to the direction of the fibers while the other refers to the size of the fibers.

Grain direction is always classified in reference to the long dimension of a piece of paper. In other words, a 9” x 12” piece of paper that is manufactured to be long grain would have paper fibers that run parallel to the 12” direction, i.e., long dimension, long grain. A 9” x 12” piece of paper that is short grain would have paper fibers that run perpendicular to the 12” dimension, i.e., long dimension, short grain.

Books are usually printed on short grain paper. The red arrow indicates
the recommended grain direction.

Pamplets are also printed with the folds parallel to the short grain direction.

Single sheet forms, like posters and letters, are usually printed 

long grain.

Grain direction can easily tested by tearing the paper along the long dimension and then on the short dimension. If the paper tears fairly easily and in a straight line, it was torn “along the grain”. If the tear is ragged and irregular, it means the paper was torn “against the grain”.

The long grain edge in this paper grain test tears relatively straightly,while the
short grain edge tears very unevenly.

The Importance of Knowing Fiber Content

Fiber content directly influences the image quality and aesthetic preferences for a printed image. That’s why papers are made with different fiber contents. Stronger, harder surface papers produce a higher degree of “ink holdout”. Ink holdout refers to the degree in which ink is able to remain on the surface of a piece of paper without being unnecessarily absorbed. A high ink holdout produces a cleaner and sometimes glossier ink jet dot. So, 100% cotton fiber papers, which have a high ink holdout produce a much sharper image than say, newsprint, which has a very low ink holdout and produces a fuzzier image.

Hardwood fiber comes primarily from deciduous trees. The fibers in hardwood are shorter making paper more flexible and smooth.

Softwood fiber comes from almost exclusively conifer trees. The fibers in softwood are longer making paper more strong and rough.

Cotton fiber is made from 100% cotton fibers. Cotton fibers are both stronger and more durable than wood pulp-based paper.

Recycled fiber is made from various sources. Recycled fiber can be very high quality. Non-post consumer recycled fiber from unused repurposed paper is superior post consumer recycled fiber.

The Importance of knowing Grain Direction

Grain direction affects the ability of a piece of paper to fold properly. Paper folds best with the grain, so it is important to have the grain direction parallel to the fold. Paper that is folded along the grain will have a smooth very neat fold, whereas paper that is folded against the grain will tend to crack leaving a rough unappealing edge to the fold. Some digital paper manufacturers will specify the grain direction for the consumer. The Moab Paper Company denotes the paper as “GL” for grain long, or “GS” for grain short. Printed materials that have folds such as books, brochures, greeting cards, etc., are prime candidates for short grain papers, while posters, post cards, flyers, etc. are best printed on long grain papers.

Note: Paper coatings and surfaces will be the subject of a future post.

Digital File Formats

As illustrators we use a few digital file formats in the course of the work we produce, and even though knowing about them is important, we tend to take them for granted. Especially when the software we are using offers up convenient default options for formatting and saving our files.

The Basics of File Extensions

Firstly, it is important to know what a file extension is. A file “name” extension is the suffix that is attached to a filename. For instance, My Illustration.tif, where “My Illustration” is the file name and “.tif” is the extension. The extension identifies the type of file I have saved. The important thing to note is that the file extension is the code that a software program will use to recognize and open the file. And in the case of the .tif extension, there are many software applications that can recognize and open a .tif file.

File extensions can be application specific, cross-program, or cross-platform.  Since each software application usually has its own file extension, there are tens of thousands of file extensions patented. Nowadays, the file extensions suffix is automatically attached to the file name. This is not only essential for a software program to recognize the file, but it is also very helpful for a user. Back in the day suffixes weren’t displayed, so one often had to go to “File Info” to check the format. In the too much information category, the longest file name extension registered at this time is the 25 letter + dot “.bejeweled2deluxesavedgame”. This doesn’t help when the total length a file name including the extension can be is limited to 255 characters.

This post is going to highlight cross program image based file extensions such as .tiff, .eps,, etc.; rather than application native ones such as .AI (Adobe Illustrator) or .PSD (Adobe Photoshop Document) file formats. It is also going to focus on those that are most commonly used by illustrators.

The Reason for File Formats

In a nutshell, the purpose of a file format is to preserve the accuracy and appearance of a digital document for a desired context. That’s why it is very important to know the purpose, uses, and limitations that were designed into the various file formats to avoid usage mismatches or loss of data. For instance, saving a 24-bit RGB Adobe Photoshop document in a .gif format will reduce the number of colors from 16,777,216 down to 256, i.e., 24-bit down to 8-bit, which could have drastic consequences depending on the output requirements for the file.

The Formats

TIFF

TIFF stands for “Tagged Image File Format”.
.tif files can be raster or vector based images. .tif supports black-and-white, grayscale, index color (256 color), RGB, LAB, and CMYK images and offers excellent compression options including  LZW (Lempel-Ziv-Welch) lossless compression. A .tif file embeds an ICC color space profile, which means many applications can access .tif files. .tif files can be reopened and edited. A non-flattened Adobe Photoshop .tif file will save layers, adjustment layers, channels, paths, and transparencies, but programs that can read a .tif may not be able to read all of the these features. Presently, Photoshop supports 16, 24, and 32-bit depth images.

JPEG

JPEG stands for “Joint Photographic Experts Group”. The .jpg format operates strictly in the realm of raster imagery. .jpg produces lossy compression, which can result in a lessening of image quality. Vector graphic documents that are saved as .jpg files will be rasterized, resulting in a loss of their resolution independent scalability. There are two main reasons for using the .jpg format. The first use is to loose data. Now it sounds like this would be a bad thing, but in actuality, loosing data or shrinking a file can be very useful. For instance, you can create a high resolution illustration and retain an original file for many different uses. If one of those uses is to display that image on a website, you can compress the file by saving it in the .jpg format. The ,jpg format allows you to set the image quality, i.e., the image size, when you save your illustration, making it very small if needed. The second reason to use .jpg is that stores 24-bits per pixel, 16,777,216 colors for a realistic true color look. Most significantly, the .jpg format supports RGB, CMYK and grayscale color spaces.

JPEG low resolution color sample.

JPEG maximum resolution color sample.

EPS

EPS means “Encapsulated PostScript”. A format that was once quite popular, .eps encapsulates raster and vector image files in PostScript code. There are two main purposes for using an .eps format. One was to export an image that could be placed into another document, such as an illustration file that would be placed into a page layout program for final output. A placed .eps image retains its integrity; it can be scaled, but not resampled or content edited. .tif files can also be placed inside other documents and offer greater flexibility than .eps files. The other main purpose is to save a file in encapsulated PostScript to be output directly on a PostScript printer. .eps files can produce lossy compression in raster based applications like Photoshop.

PDF

PDF is the acronym for “Portable Document Format”.
Based on PostScript, it was developed by Adobe Systems as a highly compressed, efficient way to format documents for platform independent readability. Another hallmark of a .pdf file is that it will look the same on screen as it does in print. The .pdf format has several quality variations available. For instance, Photoshop offers “Press Quality”, for high quality output on an imagesetter or platesetter, however, the file is CMYK down sampled to 300ppi for efficiency. Another offering is “Smallest File Size” where the file is down sampled to low resolution RGB for use on the web. .pdf is useful for saving page layout files with single or multiple pages with images,  text, fonts, graphics, and multimedia content. .pdf has grown greatly in popularity due to it’s extreme usefulness for viewing documents on all sorts of platforms like the iPad, iPhone, etc.

GIF

GIF is the abbreviation for “Graphics Interchange Format”. It is a raster image format that maxes out at 8-bits per pixel RGB, or 256 colors. At one time the .gif format was the most popular format for saving files for use on web documents. Due to its limitation on colors it is not generally used for full color illustrations or photography, although .gif is an excellent format for certain purposes such as illustrated icons and graphics with limited color schemes.

GIF 256 color sample.

GIF 256 color sample with maximum pixel dithering.

PNG
PNG stands for “Portable Network Graphics”. Preceded by .gif, the .png format has all but replaced .gif for use by illustrators when converting images for the web. .png is known for lossless compression in a raster image format. Another advantage over .gif is that the .png format comes in two sizes; PNG-8 or 8-bit per pixel, and PNG-24 or 24-bit per pixel; 256 colors and 16,777,216 colors. PNG-24 can handle full color illustrations and photographs while PNG-8 is better suited for limited color images. One limitation of .png is that it only supports the RGB color space. For this reason .jpg is the preferred format for full color images, but .png may be a better choice for illustrations that use a limited color pallet or solid colors.

PNG-8 color sample, 256 colors.

PNG-24 color sample, 16,777,216 colors.

SVG
The SVG file type is primarily associated with “Scalable Vector Graphics”. SVG is a language for describing two-dimensional shapes, text, and embedded raster graphics. Although not a natively supported by Adobe, SVG images can be created and exported from Adobe Creative Suite programs, such as Illustrator for use on the web. SVG is ideal for interactive, data-driven, personalized graphics. It is widely supported by modern web browsers.

Best Usage Summary

.tif – For CMYK illustrations for commercial printing

.tif – For RGB/CMYK illustrations for high quality desktop output

.tif – For CMYK illustrations placed in other application files

.jpg – For RGB/CMYK full color raster illustrations for desktop output or web

.eps – For illustrations for output on a PostScript device

.pdf – For illustrations for emailing, digital display or desktop output for proofing

.png – For illustrations with limited color for the web (PNG-8)

.png – For full color illustrations for the web (PNG-24)

.svg – For two-dimensional vector graphics for the web

One Final Word

For archiving I recommend using the native application file format and .tif. As long as applications are updated to be upwardly compatible, the native file format will be best. I use the .tif format for insurance.

How Adobe Photoshop Runs

It’s important to know how the software and hardware we use to create our illustrations works. These days, most of us never even think about how we are able to create the digital images that we do. Except on that rare occasion when we run into a problem. That’s because software developers like Adobe have done an incredible job automating things to make our digital work easier. It wasn’t always that way in the past. Nowadays, the learning curve we experience with software programs focuses on tools and techniques, rather than on how to get the software and hardware to cooperate with each other.

Performing operations in Photoshop takes a great amount of processing power. 

To do this Photoshop accesses the hardware chip RAM or “random access memory” that is available for software processing of operations. This is fairly typical of how all applications work. However, for complex operations, which are most of the processes in Photoshop, the program quickly uses up the hardware RAM. So Photoshop makes its own RAM, which is called a “scratch disk”, by converting unused hard drive memory into “virtual RAM”. So, the more open hard disk space your computer has available, the more fluidly Photoshop will work for memory intensive tasks, and you probably won’t even be aware that Photoshop is doing it. When there isn’t enough free space available Photoshop will produce a “Scratch Disk Full” or “Scratch Disk Error” message. 

Example of a Photoshop scratch disk error.

For those who store their entire music library, photo library, and video library on their computers this can easily happen. The key is to look for a solution that will have the lowest impact for you. Below are some suggestions.

Suggestion 1

Purge your hard drive of non-essential files by archiving them or moving them to a storage device. iTunes also has a habit of creating and storing duplicates of your music files.

Suggestion 2

Close applications and startup items you are no longer working with. Applications including Photoshop create temporary “.tmp” files, like files that are held in the clipboard. If you have several applications or documents open there can be several temporary files hanging around. On a personal note, I have found that streaming a music service to your computer while you are also working on it can slow things down.

Suggestion 3

Add more “virtual RAM” to Photoshop. Select Photoshop's preferences (Photoshop > Preferences > Performance) and use the Memory Usage area of the screen to adjust the memory allocation. Adobe recommends the allocation to be approximately 70% of available space.

Memory options allow a user to control the virtual RAM.

Suggestion 4

Adjust the image cache and/or the number of history states. Essentially, the image cache takes snapshots of the screen that are used to speed up the refresh/redraw process. So when a portion of an image is changed, the computer can quickly redraw the changes without having to reprocess everything in the image that wasn’t changed.

The history keeps a legacy version of the image for each alteration that occurred through a given number of states. In Photoshop the default number of history states is 20. The more history states designated the more memory is used to maintain them. Select Photoshop's preferences (Photoshop > Preferences > Performance) and use the History & Cache area to make adjustments.

History and cache options allow a user to control the number of history 

states and the cache levels.

Suggestion 5

Purge clipboard, undo and history. This is a short-term option, however if you know you won’t need to use your history states, or the clipboard it might be worth your while to take advantage of these house cleaning options. From the edit menu select (Edit > Purge).

Purge offers options to clear undo, clipboard, and history.

Suggestion 6

Designate a different drive as the scratch disk. This is an Adobe recommendation. Even terabyte capacity hard drives are now relatively affordable, and you should have a second drive to store your files on as insurance anyway. I’m always amazed when I talk to illustrators who are working without any form of file backup. I recommend a second drive rather than a drive partition.

The default scratch disk is the same disk that has contains the computers OS. To designate a different scratch disk, select Photoshop's preferences (Photoshop > Preferences > Performance) and select the disk that you want Photoshop to borrow RAM from. In the example below, I can more than double my available scratch disk space by selecting a second disk drive.

Scratch disk options allow a user to customize drive selection.

Suggestion 7

Be efficient with your file size. Don’t short change yourself for possible resolution needs in the future, but don’t think you need to use the maximum file size Photoshop will support of 30,000 x 30,000 pixels and 200” x 200” either. Photoshop offers an option to check the efficiency of your document.

The document status panel offers the option to check the document efficiency.

High Impact Suggestions

Other options remain, but I would classify them as high impact, such as buying a new computer, replacing a CPU, adding RAM chips, etc. There are also some workarounds that involve strategies that will result in data loss that I would avoid, such as changing the bit depth of your file to speed up performance, or reducing image resolution to make operations behave better.