So far we discussed the types of graphical illustrations, i.e. the “What”. Now we will discuss the creation of the graphical illustrations and their integration into your Technical Report, i.e. the“How”. But before you start, you have to make some preliminary decisions.
Preliminary decision 1: paper based or digital?
Printed photos are still used today, e.g. for metallographic micrographs in damage anal- yses, for photos of plants, as press photos etc. However, digital photos, scanned images and images from the internet are used much more frequently.
If you want to use colored images from books and brochures in your Technical Report, scan the image and print the page on a color printer. Later you can reproduce this page of your Technical Report with a color copier. Colored photos can be glued into each copy of the Technical Report. The handling of black-and-white graphics with brightness gradients and black-and-white photos is similar.
Paper based images can be manually created drawings of all types including sketches used as illustration in computations, mind maps, comics, design drafts etc. They are used whenever speed and creativity are important. However, in the meantime the usage of graphics and CAD programs is the standard.
Preliminary descision 2: use of graphics and CAD programs?
Using CAD programs saves a lot of time when you modify an existing part, when there are repeat parts and part families. When using CAD programs, the effectivity is much dependent on the task. CAD programs are often too complicated for casual users. They have so many functions, that you have to train and practice using the program. That is also true for graphics programs. Therefore, the advantages and disadvantages of graphics and CAD programs will be shown in the following overview.
aspect 1 aspect 2 generic term
aspect 1 aspect 2 generic term Fig. 3.24 Examples of
pictorial re-arrangements of text
Advantages and disadvantages of graphics and CAD programs Advantages:
– The graphics look tidy, there is a consistent overall impression.
– By using fill colors andfill patterns, area graphics can be created.
– Changes can be done quick and easy. (You should use a graphics program, which allows drawing on different levels—also called slides or layers.) – The graphics can also be integrated in word processing or desktop pub-
lishing (DTP) programs. This enhances the Technical Report optically.
– If you use CAD programs, a perspective 3D display and the different views can be easily created once the object data has been entered.
– Employers expect that you have learned how to use standard software (graphics as well as CAD programs) during your study course or in an autodidactic approach. Therefore the time you invest in learning to use these programs is not lost.
Disadvantages:
– The time and effort you have to invest in learning complex graphics pro- grams and for drawing PC graphics is quite high (depending on the pro- gram). The user interface is sometimes confusing and the time to get first results is so long, that drawing the figures with a simpler program is the better solution for the moment. Pixel graphics programs as well have dif- ferent concepts for the user interface. If you have to work a lot with pixel graphics (e.g. with images from digital cameras or with GIF and JPGfiles for the internet/intranet), learn the creation and editing of these files early enough.
– Especially scanned figures sometimes can have different scaling factors in x and y direction. In addition, if you do not mention it, circles are no longer round! It is better to assign the scaling factors numerically.
– If after scaling your figure there are Moiré effects (checkered or striped pattern), undo the scaling and test scaling factors which are a multiple or a fraction of the original size by the factor 2 (factors 25, 50, 200% etc.).
– If after scanning afigure with a scanner there are Moiréeffects, check that with the zoom function of your graphics program. Perhaps it is just a screen display problem. Moreover, it helps sometimes, to put a thick glass plate onto the scanner and to put the figure to be scanned on top.
No matter which software you use—sometimes it lasts quite long to create PC graphics, but you will be rewarded with good-looking results. The following overview shows important facts about graphics and CAD programs.
▸ You should decide early, which graphic you want to create with which pro- gram. Probably this decision will be influenced by possible license fees and by which programs are used in your working environment. Then you should learn how to work with these programs well before the end of your project, if that is necessary.
An exact estimation how long you need to create digital drawings is normally harder than it used to be when drawing by hand. Therefore, we recommend the following:
▸ Create graphics files as early as possible. Take into consideration that it lasts longer than you estimated, even if it was a generous estimation! In pixel graphics programs, using image effects can cause unexpected results. Test the functions of your graphics program on a copy of your data. Also, try out the integration of the graphics into your word processor or DTP program and the printed results as early as possible.
The nextfigure is a vector graphicsfile created with a graphics program, which looks attractive due tofill colors andfill patterns, Fig.3.25. In the original work the author had drawn this illustration by hand with drawing ink and added thefill patterns with scratch foil.
▸ If the drawings shall look proper even in detail, you should zoom-in into tricky areas from time to time and check whether your graphic still looks tidy in the enlargement. Often you cannot see areas, which are drawn untidy in 100%
scaling on the screen, but the printer will show everything much more precise.
Also create test printouts of your PC graphic from the word processor program. If possible avoid that in your word processor or in a graphics program several objects are lying on top of each other in one level, e.g. by using a different graphics program which enables working on different levels (layers). If several objects are lying on top of each other, you have to move the objects lying in the front to be able to select and edit the objects in the back. Then you need to reposition the objects in the front as they were arranged before. Grouped objects sometimes have to be ungrouped and grouped again later etc. All this is time consuming but inevitable without level management.
Preliminary descision 3: vector or pixel format? Which file type?
CAD programs internally use objects and create vector graphicsfiles. Graphics programs either create pixel graphicsfiles (the image consists of pixels) or vector graphicsfiles (the image is a collection of objects).
If a line drawing is saved as a pixel graphicsfile, it is quite large, because for every single pixel the brightness and color must be saved. However, pixel graphicsfiles are well
suited for halftone images (with continuous color and brightness gradients) and for scanned photos.
Vector graphics files use a different concept. If on a large area a circle is to be displayed, a pixel graphicsfile would become larger with increasing diameter. The vector graphicsfile does not change its size very much, because the only data stored in the vector graphicsfile are center point coordinates, radius and line thickness, style and color. For a straight line, the only data stored are starting and end point coordinates and line thickness, style and color. These graphicsfiles are much smaller. Therefore, vector graphicsfiles are better suited for line drawings than pixel graphicsfiles.
File formats for pixel graphics files (also called raster graphics) are e.g. BMP, GIF, JPG, PNG, and TIFF. The three formats GIF, JPG, and PNG can be displayed by internet browsers and imported by most word processors. Almost all vector graphicsfile formats are vendor specific. Many vector graphics programs can read and/or write DXF. Stan- dardization efforts derive from the design and manufacturing area (CAD/CAM). They use DXF, VDA-FS, IGES, SAT, IFC, and STEP as system neutralfile formats. In thefield of technical documentation, SVG is quite frequently used, because it can be displayed in internet browsers as well.
In the following important differences between the formats GIF, JPG, PNG, and TIF are described.
welded part
protective gas
weld smoke
Fig. 3.25 Section through a protective gas welding pistol with integrated weld smoke suction (fill patterns and arrows show the direction offlow of protective gas and weld smoke)
GIF files can only display a limited number of colors. They are well suited for pic- tograms andfigures without color and brightness gradients. Another advantage is that you can combine several single GIFfiles to an animated GIFfile which runs like a smallfilm.
JPGfiles are well-suited forfigures with color and brightness gradients. If you want to display large images on the screen, the format JPG offers to save the JPG file with the option interlaced. If you look at the image online, thefigure is built up different. Atfirst the 1st, 3rd, 5th line etc. of the image are displayed so that you can see a rough outline of the figure quickly. Then the 2nd, 4th, 6th line etc. are displayed so that the image is completely displayed. JPG files do not need much disk space, but it occurs quite fre- quently that JPG files are blurred, especially screenshots.
Since both formats GIF and JPG have disadvantages, the format PNG is also used.
A detailed description of thefile format is published on Wikipedia. PNG is an abbrevi- ation of Portable Network Graphics. PNG has an image compression without losses, it supports different color depths and transparency. The image compression rate of the PNG format is normally higher than the compression rate of GIFfiles. However, PNG has the following disadvantages: more complex than GIF; no animation; not as high compression rate as JPG, but without losses; no support of the CMYK color model, which is required for four-colour printing, therefore no substitution of TIFfiles.
Avoiding distortion
No matter which format you use, please make sure that your images are not distorted.
Distortion happens, if you use a different scaling factor in x and y direction. You can best avoid these problems, if you do not rescale your images with the mouse, but via numeric entry of a scaling factor. This factor should result from a multiplication or division by 2 (25, 50, 200% etc.). Please make sure, that the option proportional scaling or maintain proportions is switched on. (The different word processors, slide presentation and graphics programs call this a bit different, but the sense of the function is always the same.) Selection of an adequate image resolution
If you scan images or create digital photos, you should plan early with which resolution you want to work. For a simple screen display GIF or JPG files with 72–75 dpi are sufficient, while for high-quality journals the resolution must be at least 300 dpi and TIFF files are preferred rather than JPGfiles.
▸ In the Technical Report 150 dpi resolution is a good compromise in most cases.
And the higher the resolution, the larger is the resultingfile size. This goes on as follows: If you insert many large image files without reference into your text files or slide presentations, yourfiles will also become much larger.
The image resolution of scannedfigures should not be too high. The image resolution for images, which shall only be displayed on a screen, is 72 or 75 dpi. In the Technical Report an image resolution of 150 dpi is sufficient for proper printouts in most cases. For four-color printing of journals and books, it must be min. 300 dpi.
Always save image files independent of and within text or presentationfile
Image files, which you use in your Technical Report or in a slide presentation, should always be stored on the hard disk drive or a USB stick as separate graphicsfiles, so that you can enter changes and apply all functions of your graphics program later on.
▸ It is best to save the graphics files in the vendor specific standard format of your graphics program and in the format, which you used to import the graphic into your text or presentationfile.
If you stick to this procedure, you can also save additional information like copyright hints, image source, thematic context, entry into the list of references etc. for each graphicsfile. If you use thefigures in a different context, like a different Technical Report or a different presentation, you can reuse this information.
Tips for Taking Photographs
In the following overview, some well-tried rules for creating photos in Technical Reports are introduced.
Rules for the design of impressive photographs Picture detail selection
– “Close”to the object or people (leave out distracting information, emphasize details).
– Select unusual perspectives (worm’s-eye view, bird’s-eye view).
– If the size of the displayed item is not imaginable for all readers without problems, other items should be shown for a size comparison, which are well known to the readers. Examples: Ruler, man, hand,fingertip, banknote, coin etc. If you just specify a measure (e.g. 1:25) most readers cannot correctly estimate the dimensions.
– Try out portrait instead of landscape format and vice versa.
– Emphasis of the front part of the image provides depth (a plastic impression).
This is especially nice, if the sides and the top part of the image are emphasized (view through an“archway”).
– Accentuations with colors make the image more vivid. Use complementary colors red + green, blue + orange, yellow + violet, but: depending on the target group not too colorful.
– Shaking hands, handover of documents, cheques, certificates and similar situations should be photographed from the head to the mid of the thigh (above the knee).
– Take enough time (wait for better light conditions, search other standpoints).
Light and shadow
– Light from the side enhances the contrast.
– Reduce backlight by covering the sun.
– Backlight plus automatic exposure without backlight correction results in black objects or people in front of a colored background (only silhouettes).
– That can be a desired result.
– Backlight and aflashlight for the front part of the image result in a harmonic light distribution.
– In interior rooms, covering light sources with bright cloth or transparent paper and reflecting light with white areas can improve the light distribution.
– Theflashlight shall not be directly reflected back from the object or person
to the camera. Such reflections distract the viewer very much form the intended photo motif and sometimes outshine important details of the image.
– Digital photos are often far too dark. In interior rooms, you should use artificial light.
Creating photoprints yourself
If you develop black-and-white-photographs on your own, you can use rasterizingfilm for the photo process. These rasterizingfilms are exposed together with the negative (a little longer exposure time). The light creates an already rasterized enlargement of the negative on the photo paper, which can be copied in black and white with an excellent quality.
Creating paper images by painting, drawing, cutting them out or by copying From childhood, we learn to paint and draw. Here it is important to use the right pencils, see Sect.3.8.3. The manually painted or drawn images are normally glued onto a carrier page of your Technical Report and copied. Partially it comes still across, that images are copied from books or journals and glued onto a carrier page of your Technical Report, e.g.
if they cannot be borrowed from a library. Also, cutting out paper images from leaflets or journals is sometimes necessary. Try to get two copies in this case—one for your personal archive and one for the paper original of your Technical Report.
When images are glued onto carrier pages and copied, some problems may occur, that need further treatment, e.g. undesired edges of the copied images. To modify photocopies you should use a magnifying glass and a drop action pencil with a soft lead, so that you can erase faults easily. Often i-dots, arrowheads and very thin lines (especially section lining) is too small or too bright in the copy. Emphasize them by redrawing! Your modified copy will be the new original and your readers will be grateful, if you invest time and effort here.
If a copied or scanned image has reference lines and labels naming importantfigure elements, there are often terminology problems. In the text of your Technical Report you are using one consistent term for the same item. In the scanned or copied image, another
term is used. Either the source is written too much in general-language or it is too theoretical and uses too many special-language terms, which you do not want to use. The situation is similar, if you want to cite from a publication, which is written in a foreign language.
Removing an undesired term from thefigure is one possible option. However, if the term shall be completely eliminated from thefigure, removing the appertaining reference line is not always easy (e.g. when the reference line crosses many closely neighbored lines or cross-section linings). In this case, it is better to cover the undesired term with the desired term (manually by gluing or with a graphics program). It is not so easy-to-read, but acceptable, to explain the undesired term with the desired term in a legend.
▸ It must be avoided in any case that afigure contains special terms, which have not been introduced so far, and that there are different names for the same items or procedures in the text and thefigure.
Didactic reduction on paper images, photos and pixel graphics
Sometimesfigures, that you want to copy or scan, are a little overloaded. Cover not so important details (with white tape or labels or photocopyfluid) and accentuate important details (e.g. with arrows or circles).
In digital photos and other pixel graphics, you can cover unimportant details with white rectangles or lines and weaken not so important parts by making them more bright and blurry with your graphics program. This is called “didactic reduction”.
Reserving Space for paper images
If afigure shall be glued in, there must be enough blank lines in vertical direction so that thefigurefits in well. The space left white for thefigure can be easily measured with the vertical position information of your word processor (line, column) or with the vertical ruler.
If you prefer paper based working, create a page with your word processor with your usual paragraph format settings. You should write consecutive numbers beginning with 1, one number per line. If you print thatfile, the numbers 1, 2, 3 etc. appear one below the other on the„line ruler“. Now you can take a ruler, measure the height of yourfigure, read from the line ruler how many empty lines that is, add two lines and enter this number of empty lines into your text file.
You can find more details about gluing paper images onto carrier pages and labeling them in Sect. 3.8.3.
Inserting graphicsfiles
When integrating graphics and scanned images into your textfiles, you sometimes have to change thefigure size. You should always enlarge or reduce the size proportionally. In the graphics program, the relevant option is called “Maintain proportions” or
“Width-to-height-ratio” or “Aspect ratio”. After importing the graphic into your word processor or presentation program, do not pick the graphic with the mouse at a corner and draw it to the desired size, but click the graphic and use the function Format—Object, tab