Document type and fonts

• kind of documents/text
• other kind of scientific materials
• typograph category or family
• contrasts
• remark on (La)TeX's fonts
  
• specify font in LaTeX
• references

Formal or techinical documents
The formal or techinical documents has specifyed and determined target audience. For example, the specialized books and articles are read by students and researchers of these area, and documents like official document, communications, etc are ready by persons that is targeted. In general, the person choice by contents, and sometimes, so chance to chice it. Thus, not necessary to catch atention of target. Since it is hard to read these kind of documents, need to use style that easy read. The contrast is to emphatize important part and not to decoration.
The techinical documents like books and articles use rige typeseting rule imposed by their editors. Moreover, several aditional elements like mathematical equations, chemical diagrams, pictures, etc are necessary. The software developed to elaborate these kind of documents normally receive denomination "scientific" and main characteristic is automation and prcsision of typeseting.The (La)TeX is developed specially totypeset  techinical and scientific documents.See example in  PDF format or LaTeX source code (requere xymtex, geometry, pgf/tikz).

The formal documents are widely used in office andsoftware to elaborate  commonly it receive the denominatio "office" and largely commertialized. The main characteristic is easy to use. See one example in PDF format or LaTeX source code (requer geometry).

Informal documents
Informal documents comprises romantic book, tales, poems, etc that normally not present fixed target audience Since they not have obligation to read, need some skill to catch atention of target, but is text is long, need to keep style simpler to read. In general, creates strong contrast on cover and chapter title, and keep style of rest of book sinpler.
The style of informal document vary much, from formal ones to advertising ones., that depends of objective and target audiences.
Since softwares for formal documents permit to elaborate these kind of documents, has less software specialized to it.
See one example in PDF format or LaTeX source code (require titlesec, fancybox, and geometry). Note that the Computer modern is cool for it, used the Palatino.

Advertising text
The advertising material are elaborated to catch atention of audience, that almost cases, are not interested to their contents yet. Thus, main goal is to catch atention. The pratical example of this vary from journal and magazines to advertising posters. The journals and magazines use more behaved style, but use strong contrast in the title of starting of blocks, but advertising materials use more strong contrast and free style with small bit of information, to catch atention. The software denominated by category "publisher" is good to elaborate these kind of materials that need advertising contents. But, in the first, the artistic talent is required. See one example in PDF format or LaTeX source code (requer fancybox). Since Computer Modern is cool fonts, TeXGyre Schola+Adventor (equivalent to New Century School Book + Avant Garde from PSNFSS) are used. See other with free styled ones in  PDF format or SVG source code elaborated by Inkscape.

Poster
Poster is kind of abstract, displayed to target audience and will use advertising elements to catch atention, but use modelately because is scientific documents. Note that the letter and picture need to be large (font of 24pt or grather) in way to readable from bit far. Use simpler fonts like sans serif or clarendun to provote easy reading. The use of picture catch atention without break rige scientifici styl, thus, hight recommended.The caution to elaborate iti is same as abstract. Thus, do not detail due to space limitations. Note that the font size 24pt (2x width and 2x height) use 4x more spaces than 12pt. since A0 (normal poster size) is 16x the A4 size, the contents of A0 poster is equivalent to 4 pages of A4 with 12pt. Thus, prepare the abstract in 4 pages of A4 to set into poster.
One of econimic form to create poster is to print several piece in A4 papers and grue it. But, it is more dificult to obtain more beautifull appearence because letter is big. Thus, divide text in several blocks and put each block inone page (use as landscape because letter is big). Puting into posters, it becames 2 column and 5 rows of A4 pages (10 pages of A4), equivalent to 2 and half pages. Thus, the qualntity of information need to be reduced much.
See one example in  PDF formato (for A0 paper), or  LaTeX source code (rquire additional pictures -- need to enlarge to A0 after typeset it, using jPDFTweak or like).

screen document (as slide style)
Is less used for scientific are. The screen slide is abstract of works like posters, designed to provide on internet or on compute, for read on thecomputer  screen. The main goal is to give idea of works and is best to avoid long contents. It is to read by one person at time, not necessary to use very large fonts like presenttion slides, but not small to promote easy readings. Set some navegation menu/button to facilitate the users. Note that the screen slides that circulate on the internet in general is informal documents and use more free styles. See one example in PDF format or LaTeX source code (require pdfscreen). See other example using beamer, in PDF format or LaTeX source code.

Presentation slidess
The presentation slides not is exactly the ``document'', and differ from above ones. The contents of these material are not necessay complete, and always are accompanied by presenters that explain over contents. The main goal of these material is to guide the presenter  and  not to be ready solery by audience. Ti prevent tiring, need to use large fonts and pictures. Use equivalent to 24pt (small room) up to 36pt (large room) for A4 papers. Use font easy to read as sans serif or clarendun. Write bit and speak much. If have much information on each slide, hide contents and show progressively as explained. The decorations need to be modelated in way to concentrate in the main contents. Cautinon to keep contrast between background and text to keep easy readings. If made print too (for example, use as abstract of explained contents for future study by student),
use contrast between background and text in dark/light form (for case that print on the black/white printers).
See simpler slide in PDF format or LaTeX source code. Other ones in PDF formats or LaTeX source code (requre beamer and additional pictures). Other ones in PDF or ODP source code elaborated by LibreOffce..

See example in PDF format or LaTeX source code (require geometry, concmath, calligra, oldgerman). For more examples, and explanations for each category, see the cooresponding links below.

Old style

• Characteristic: The lower letter has inclined serif with smooth thickness transition, with diagonal enphasis.
• Examples: Times and Palatino. See in PDF format or  LaTeX source code (require geometry).
• Effcio:  Nice and easy to read.
• Use: Apropriate to use in long text, independent of kind of text. Thus, is best choice for document body. In the scientific document, remember that the equations and pictures are part od document too.
  
• Remark: Times is used as default font for MS Word (C).

Modern style

• Characteristic: The lower case letter has serif horizontal and thin. Strong thickness trqnsition and emphasis in vertical.
• Example: See the Computer Modern Roman (that is quasi Morden) in PDF ou LaTeX (source code).
  
• Effcio: Elegant and cool, with strong visual.
• Use: Advertising.
• CAution: Do not use for long text (except tchinical and scientific documents).
  Remark: (La)TeX use Computer Modern (quasi modern, with more thick serif), as default font for body text (and equations), in wayt to take more serenity visual. See remark on (La)TeX's fonts for detail.

Slab-Serif (Clarendon or egipty)

• Characteristic: Serif of lower letter are strong and horizontal. Small bit ou without thickenss transition and emphasis in vertical.
• Examples: New Century Scool Book. See "Clarendon" and "quase Clarendon" in PDF or LaTeX source code (requer concmath and geometry).
• Effect:s Is very readable, but create the page more darker than old style.
• Use: Is direct and clear, thus used for children's book, school's text books. posters, slides, and advertising materials.

Sans Serif

• Characteristic: No serif, and no thickness transition. Thus, no emphasis (the letter has same weight in all parts).
• Examples: Arial, Helvetica, and Avante Garde. See one example of Sans Serif in  PDF or LaTeX source code.
• Effect: is very readable and has direct information.
• Use: It is easy to distinguish one letter per other, thus are used for slides, posters, and advertising materials. Sometimes use for titles, headers, and covers too.
• Caution: The Sans Serif that present thickness transition need caution to use, because is more difficult to combine with other fonts.
• Reamrk: On the MS Word (C) that use Times as body font, normally use Arial for Sans Serif ones.
  Note: The Sans Serif of Computer Modern used inn the (La)TeX presents thickness transition in way to combine with their roman fonts.

Mono spaced (type writer)

• Characteristic: Imitate the type writer letter. At first loock, seems bit as Sans Serif,but all letterhas same width, independent of letter size. The end point will be rect or rounded. and use constant thickess, including the serif. In general, the font is thin and appear as wireframe.
  
• Example: Courier. See one example in PDF or LaTeX source code.
  
• Effect: Seems like text produced by wripy writer.
• Use: For text that need to be read exactly as is, like source code, file name, address of internet, and stretch of important documents. Note that the quoted text will interpreted the mean, not exactly the letter per letter. The text in type writer fonts are interpreted letter per letter.
• Remark: On MS Word (C), usualy use Courier, although of not totally compatible with times.
  Note: The Typewriter of Computer Modern used in the (La)TeX are designed specially to combine with their roman fonts and are more thick than the usual typewriter fonnts.

Hand written (calligraphic)

• Characteristic: Imitate the hand written letters, with pencil, blush, pen, etc.
• Example: See the TeX Gyre Chorus (based in "Zaft Chancery") in PDF or LaTeX source code (require geometry and texgyre). See calligra in PDF or LaTeX source code (require geometry and calligra).
• Effect: Home maded.
• Use: Invitations, poems, etc that not necessary easy to read, but the climax is important. Will used for advertising too, if used by caution for bit of information.

Decorative

• Characteristic: Decorated letter.
• Example: See "Initial fonts" in  PDF or LaTeX source code (requer geometry).
• Effect: Artistic.
• Use: Advertising.

Remark: There exist large kind of symbol fonts containning the symbols such as matematical, music, horoscope, etc. In way to cover these symbols, the (La)TeX has more than 2.500 symbols and special fonts. See the  Comprehensive Symbols List (CTAN).
Fonts for (La)LaTeX: To see fonts available for (La)TeX, see the  http://www.tug.dk/FontCatalogue/allfonts.html.

If only bit of contrast exists, seems like mistake, denominated "conflict". In way to avoid conflict, sometimes will need to combine more than one element chage for contrast. Note that on the scientífic documents, contrast need to be modeled to keepmore  redablee.

• size: font size, like between title and text body. See font size available for LaTeX in  PDF or LaTeX source code.
  
• weight: font thickness like light, regular (or medium or book - normal), semi bold, and bold. In general, use bold to ephatise important words.  In general, light aand semi bold are not used, because is take only bit of contrast with reagular and bold. See font weight in (La)TeX in  PDF or LaTeX source code.
  
• structure or category: The construction (category or family). Do not use two fonts with same category on same page (like two old style, two Sans Serif, two moderns, two calligraphic, etc), because it raise conflict.Some times, the difference between category are not sufficient to distinguish easily each others. In this case, combine with other lement of contrast. See family on (La)TeX in PDF or  LaTeX source code.
  
• shape: letter shape, such as between upper case and lower case, roman and italic/hand written, etc. Note that the text only with uppercase letter not is much readable and need caution. The straight and slanted romann (not italic) has only bit of contrast nad need to combined with other contrast elements. Note that the italic and hand written fonts are low contrast too. See basic shapes on (La)TeX in PDF or LaTeX source code.
  
• direction: rotation and column that used (title using two column of text, text in vertical, etc). Use by caution. See example in PDF or LaTeX source code (require picinpar).
• color: Include density too. For example, shape, weight, and density creates the "color" too. See color talbe of (La)TeX in PDF or LaTeX source code.
  

(La)TeX use Computer Modern with thicker serif, developed by Kunuth as default font for body text (and equations). The (La)TeX is developed specially for scientific docuemtn and thus, it use quasi-modern fonts that give seriousness view due to their cool appearance. Since this font is hard, not suitable for informal documents. For this, use old style fotns like Times or Palatino.
In the scientif or techinical documents, all fonts need to combine each others. Computer Modern becames with three family of fonts: Roman (quasi modern), Sans Serif, and typewriter. Moreover, almost symbols developed by Kunuth and AMS is conform to these fonts.
See the example in PDF or LaTeX source code (require geometry) that presents coherent font combinations. Compare it by combination of Times, Arial, and Courier usualy adopted by MS Word (C) users in PDF or ODT source code elaborated by Libre Office, that does not present these coherence (for example, compare the thickness of "typewriter" with other fonts).
Due to their hardness of Computer Modern, several people used the Times. Sometimes it decrease typeseting quality due to lack of free fonts. The journals, for example, will use "MathTimes"  with commertial fonts, or use commertial version of (La)TeX that becames with professional quality Times fonts. However, the free alternative that combine Times, Helvetica and Courier of PSNFSS font sets, does not give same coherence of Computer Modern. See an example in PDF or LaTeX source code (require geometry). Attenpt to use Palatino from PSNFSS is the same. See an example in PDF or LaTeX source code (requer geometry). To guarentee quality on PSNSS fonts, need to skip aditional fonts and symbols like from AMS ones. Appear packages to use fonts from Windows, but the combination of Times, Arial, and Courier have same problems.
Motivated by need of free fonts based on old styles like Times, the "Young Ryo" developed set of Post Script font for (La)TeX, named "txfonts" (Times) and "pxfonts" (Palatino). These fonts have almost all aditional fonts and symbols of computer Modern equivalence and AMS equivalent ones. Thus, now will produce documet with very coherent font use based onTimes and Palatino in (La)TeX (using newtxtext,newtxmath for Times and newpxtext,newpxmath for palatino). See one example of "txfonts" in PDF format or LaTeX source code (require geometry and txfonts), and an example of "pxfonts" in PDF or LaTeX source code (require pxfonts and geometry).
In way to typeset scientific document using Clarendun like fonts, will use Concrete Roman,since it not use additional fonts and symbolsoutside or standard (La)TeX ones and from AMS ones. See one example in PDF or LaTeX source code (require concmath).
For persons that does not use equations, more several fonts is available from PSNFSS font set. The TeX Gyre implements fontset  based on these PSNFSS. See the examples: The TeX Gyre Schola (based on New Century School Book) in PDF or LaTeX source code (require geometry and TeXGyre), TeX Gyre Bonum (based on Bookman) in PDF or LaTeX source code (require geometry and TeXGyre), TeX  Gyre Chorus (based on Zaft Chancery) in PDF or LaTeX source code (require geometry and TeXGyre), TeX Gyre Termes (Times type) in PDF or LaTeX source code (require geometry and TeXGyre), TeX  Gyre Pagella (Palatino type) in  PDF or LaTeX source code (require geometry and TeXGyre), TeX  Gyre Heros (Helvetica type) in PDF or LaTeX source code (require geometry and TeXGyre), TeX  Gyre Adventor (Avant Garde type) in PDF or LaTeX source code (require geometry and TeXGyre), TeX  Gyre Cursor (Courier type) in PDF or LaTeX source code (require geometry and TeXGyre). Moreover, the PSNFSS provvides an special package "pifont". See an example of pifont in PDF or LaTeX source code (require geometry).
There exists packages and fonts specially developed to slides and posters. See one example of Iwona font in PDF or LaTeX source code (require geometry and iwona).
The (La)TeX has several other fonts available on CTAN. See an example of caligraphic fonts in PDF or LaTeX source code (require calligra and geometry), Old German in PDF or LaTeX  source code, "initial fonts" in PDF or LaTeX source code (require geometry). To have an idea of diversity of fonts for (La)TeX, see  http://www.tug.dk/FontCatalogue/. If desire to install htese or other additional fonts, see the  CTAN (http://www.ctan.org/tex-archieve/fonts) first, but remember thatsome package from CTAN will reauire commercial fonts. If prefir, some true type fonts from Windows will used to, but to keep typeseting quality, need to learn over correct use of fonts on documents. The use of system fonts  are not so recomended, because of portability of documents.
Note that the Xe(La)TeX and Lua(La)TeX allows to use system fotns easylly.

On (La)TeX, the font are specified bycategory  font family,weight (font series), shape (font shapes, and sizes.

Family: use three basic family: rmfamily (Roman: font with serif such as Modern, Slab-Serif, or old style) used for body of document.and equations. sffamily (Sans Serif: font without seriffaused for slides, posters, titles, e. and ttfamily (Typewriter r mono spaced: wireframe font)
that used for source code, file names,part of important document, etc that need to be interpreted letter by letter (on the quoted text, the importance are mean, not letter per letter).
Note that these family of fonts need to have coherence. If roman family of fonts are changed to Times, other two need to changed to font coherent to Times. Thus, in genral, use suitable font package to do this task.
See  notes on fonts of (La)TeX for more detail.
Remark: The default font family for body text of documents is specified by  \familydefultthat will altered, if desired. For example, for slides or panel, will change to \sfdefault that is more suitable. See example of these three font family (using Computer Modern) in PDF or LaTeX source code.

Weight (series): used to emphatize some important words. There exists two basic weights that is mdseries (is mediun, normal) and bfseries (bold to hightlight). See an example in  PDF or LaTeX source code.

Shape: To emphatize, but not much hightlight as bold, will use change of shape. The \upshape (Upright, normal) and \itshape (italic) are commonly used. To alter between theses, use \emph{}. Other less used shape are \slshape (Slanted or oblique) that require to used in conjunction to other contrast element, and \scshape (Small Caps, all in uppercase form, but with different sizes) that need caution to use.
See example of shape in PDF or LaTeX source code.

Reamrk: In way to create block of text with above settings, use the \textxx{text} where "xx" is two first letter of family, serie or shapeabove. These commands will be combined. To use normal font, use \normalfont or textnormal{}. to empahatize, use \em or \emph{} that alter between upshape and itshape. Note that the change of font of text does not change the font on equation that require to made independent of this. The \textxx{} equivalent for equations is \mathxx{}, where xx are one of rm, bf, sf, tt, it e cal. It works gottheger with text fonts. The \mathcal{} use calligraphic font shape (only uppercase) used for mathematicians. The AMS include \matbb{} that is Blackboard Bold, used to represent set of numbers like integers, real, complex, etc (there exists more Blackboard Bold fonts like \mathds{} from dsfont). In way to return as normal font inside \mathxx{}, use \mathnormal{}.
sometimes, need to keep equations in bold to combine with bold text. In this case, use \mathversion{bold} and \mathversion{normal}, to activate or desactivate bold version of equations. Mote moreover that the text inside equations will inserted by \text{} from AMS.

Size: The size (smaller to bigger) are: \tiny, \scriptsize, \footnotesize, \small, \normalsize (normal), \large, \Large, \LARGE, \huge, \Huge. These commands given the relative size from base size (standard base size are 10pt, 11pt, or 12pt). Not recommended to use size not given by these commands, because will cause conflic orincoherent sizes.See size example in PDF or LaTeX source code.

Remark: Will change the text color too, but if typeseting the scientific document, need caution. See the command and color table of (La)TeX color
 in PDF or LaTeX source code (require geometry and xcolor).

[1] Willians, R., (tradução: Gillon, L. K.) "Design para quem não é designer (noções básicas de planejamento visual)", 1994 - Callis Editora
[2] Goossens, M. et al., The LaTeX Companion, seccond edition, 2004, Adilson Wesley.
[3] several documents distributed toghether LaTeX (http://www.ctan.org)
[4] documents distributed by project LaTeX 3 (http://www.latex-project.org/).