Department of Computer Science and Technology

Technical reports

Instructions for submitting a new technical report

Suitable material

Technical reports are intended primarily for the long-term archival of results and descriptions that are not suitable for submission to a journal or publication as a monograph due to their length or nature. Technical reports should be prepared to a quality standard comparable to that for other scientific publications.

Technical reports are also a way to make a PhD thesis widely available. This has become somewhat less common since the University started in October 2017 to require (in addition to the hardbound PhD thesis) an electronic copy to be submitted, which it now routinely publishes on the Apollo repository in the Theses – Computer Science and Technology collection. However, we still happily accept PhD theses as technical reports, especially as some authors want to publish an edited or updated variant of their thesis that is not exactly the version approved by the examiners.

Technical reports are not intended as a medium to disseminate preprints of papers that are awaiting review and publication. For these, better use your departmental web home page and/or one of the various preprint servers (arXiv CoRR, Computer Science Preprint Archives, Cryptology ePrint Archive, etc.).

The Computer Laboratory Technical Report series is mainly intended for work done at our department, or in collaboration with a member of our department.

Online publication procedure

Since 2002, technical reports published by the department have primarily been released electronically, as PDF files with a common title-page layout. The title page will be generated by the technical-report editor automatically from the report’s database record. Where a print version of the report is produced, it will just be a printout of the PDF file and the title page will also be used for the cover page.

Submission requirements

In order to prepare your document for publication as a Computer Laboratory Technical Report, it may have to be slightly reformatted. This is in particular the case if the original document was formatted according to particular thesis submission or book publisher requirements that consume too much paper for a report. PhD authors who follow our local thesis layout recommendations rarely have to reformat anything. Beyond the standard title page and a few very simple technical and format requirements, there is no strict standard page layout, font scheme, bibliographic reference format, etc. specified. However, feel free to use the available LaTeX examples for short paper-style and long thesis-style reports as a simple starting point.

We generally advise against using the LaTeX style of a commercial publisher (Springer, IEEE, ACM, etc.). This is not only because many of these styles were not designed for A4 paper, but also because publishers hold typographic copyrights on these styles and readers will associate the more well-known styles with the publisher’s brand.

Please read the following guidelines and instructions carefully:

  • Provide a PostScript or PDF file of your submission. DVI is also acceptable if you did not embed any graphics files.
  • Format for double-sided printing on A4 paper. In LaTeX, use the twoside,a4paper options. (In particular, please do not use the popular LaTeX LNCS style, which is designed for a 152 mm × 235 mm book page, not for a 210 mm × 297 mm A4 page. If you really must use the LNCS style for some reason, please magnify the PostScript file with pstops [Javascript required](-2.95cm,-4.5cm)' [some prefer pstops [Javascript required](-2.40cm,-3.7cm)'] to end up with reasonable margins on A4 paper.)
  • Make the page margin on each side between 20 and 30 mm wide. Reports may be printed quite a number of times, so please choose a layout that makes good use of the A4 page and does not produce unnecessarily many pages. Thesis binders have similar requirements. LaTeX users might use something like:
  • The document should use normal line spacing (that is, not the one-and-a-half spaced lines prescribed sometimes for submitted dissertations or manuscripts).
  • Number the pages in the provided file starting from 3. This will leave room for the title page and its back side, which will be added by the technical report series editor. (LaTeX: \setcounter{page}{3})
  • Do not provide your own book-style title page. The standard title page (page 1+2) that we will prefix to your file will already provide all the relevant bibliographic data, including a copyright message. Your first page (page 3) should typically contain an abstract or summary. (In a printed copy, the title page is the first printed page. If you bind a printout of a report with an additional paper cover, you should print the title page content (page 1) in addition also onto the front cover page. The traditional cover colour for bound Computer Laboratory techreports was a light blue, but most people today simply use an unprinted transparent cover page instead.)

    If your report looks more like a compact paper or article (title, abstract and introduction are all on the same page, potentially double-column) rather than like a book or thesis, then it is fine but not necessary to repeat the title and authors on the top of page 3. If you do that, please do not add a date (LaTeX: \date{}). Capitalise in your title only the first word and proper names (that is use English-style and not US-style titles, just like titles are written in the University Library catalogue), because that is how it will appear on our standard title page. For consistency, it may be a good idea to do the same in section headings.

  • Number the pages in your file continuously throughout the document. In other words, do not number front matter (abstract, table of contents) separately in Roman numerals. This ensures that the printed page number and the page number shown by a PDF browser are identical, which simplifies the on-screen use of the table of contents and other page-number references. This practice also conforms to the relevant international standards for technical reports and theses. There is no need for a page number to be visible on each page, but it should increase by one on each page. (LaTeX: do not use the book class; you can use the openright,twoside options to get the same layout with the report class).
  • A technical report that is based on a thesis and the thesis itself are two distinct documents. There is in particular no need for a technical report to fulfill the Board of Graduate Studies format requirements, such as the declaration that you wrote it yourself and that it satisfies the length limit. Authors are free to make changes to a thesis before submitting it as a technical report, because the publication of the technical report is not part of the examination process. Some authors add the names of their thesis examiners to the acknowledgement section of the technical-report version. If the report is based on a thesis, then the back side of the title page will have a note on this, which will also provide the submission date of the thesis and the name of the college.
  • Avoid redundant legalese. You do not need a copyright statement in the submitted text; the back side of the title page will already carry one. There is no need to add a section on acknowledging trademarks. You are free to use any registered trademark to identify goods and services of the trademark owner (see Trade Marks Act 1994, s10(6))).
  • While the online version of a report can be in colour, please keep in mind that any printed versions produced by the department will be in black and white for the foreseeable future (exceptions might be possible where necessary). Therefore, any use of colour in diagrams should preferably not be essential for understanding the presented information. If this is not feasible, you can ask the series editor to add an appropriate warning to the back side of the title sheet.
  • If you use the hyperref LaTeX package:
    • use option pdfpagelabels=false
    • if you submit a PostScript file, use option dvips
    • preferably deactivate the colourful boxes around links with option pdfborder={0 0 0}
    Typical invocation:
    \usepackage[pdfpagelabels=false,pdfborder={0 0 0}]{hyperref}
    If you really want to colour the text to mark hyperlinks, please use only dark blue; the bright default link colours look rather ugly on black-and-white printouts.
  • File size: We aim to keep the size of the published PDF below 5 MB, not least because Google Scholar does not index PDFs larger than 5 MB. Our experience has been that most well-illustrated PhD theses fit in less than 3 MB. If a PDF ends up much larger, this is usually due to an inappropriate choice of resolution or encoding for some included images. Here some suggestions of how to keep the PDF file size reasonable:
    • Resolution of photographs: Modern cameras can output images more than 4 kilopixels wide, which is nice for printing large-format posters, but inappropriate if the image appears on the printed page just 16 cm wide (160 mm / 4000 = 40 µm ~ 635 dpi) or less. Laser printers can't make use of greyscale or colour-image resolutions larger than about 300 dpi, therefore please keep the pixel size in such images above about 85 µm. The tech-report editor can use ghostscript to resample your images in submitted PDF files if needed (and will do so by default if you submit a PostScript file), but you may want to choose the appropriate image resolution yourself.
    • Resolution of line drawings or bi-level scans: For included bi-level images (which consist only of black and white pixels), pixel sizes down to about 40 µm or resolutions up to about 600 dpi are appropriate. Again, we can use ghostscript to resample your images in submitted files.
    • Rasterize vector graphics with too many data points: Plots should normally be included in a vector-graphics file format (PDF or EPS), for maximum display quality at any resolution. However if your vector plots include more than a few thousand data points, this can lead to excessive file sizes. In this case, prepare them as a PNG file, with a pixel size not smaller than about 40 µm (without ant-aliasing) or 85 µm (with anti-aliasing), before including them into your report.

      Try a PDF rendering tool like

      pdftoppm -png -r 300 [-mono | -gray] figure.pdf
      (see Ubuntu package “poppler-utils”) or Ghostscript to rasterize selected individual figures before including them into your report.
    • If you produce a PDF file, you can sometimes significantly reduce its file size by loading and saving it in Adobe Acrobat (available on the departmental Windows server), as this merges embedded fonts that were included multiple times via included figures.
    • Please avoid the use of graphics (e.g., logos) in running headers or footers, as these can increase the file size enormously.
  • When you use (La)TeX with Computer Modern fonts, use the Type1 outline versions in the PDF or PostScript file, not the old Type3 bitmap fonts. The following diagnostic commands should not output anything:
    pdffonts file.pdf | grep 'Type 3'
    grep '%DVIPSBitmapFont:'

    Using the LaTeX textcomp package or T1 font encoding can trigger the use of pixel fonts.

    Matplotlib has become another source of Type 3 fonts: it wraps TrueType fonts (such as its default font DejaVuSans) into Type 3 format to subset the font. While an ugly hack, such use of Type 3 in figure labels is of less concern, as it does not indicate use of a pixel font. Ideally, use in figures some font already used elsewhere in your report.

  • When you have checked all of the above points, contact the technical report series editor (currently Nicholas Cutler or Markus Kuhn) and provide the following information in your email:

    The series editor will then assign a technical report number, generate a database record and put your report together with the standard title page onto the web server. Technical report numbers are normally not assigned before the actual report has been submitted. The date shown on the title page will be the month and year in which the final report was submitted.

    If you really must have a technical report number in advance (usually because you want to submit two reports that reference each other), then please submit all of the above information, a draft version of the report, explain why you really need the number in advance, and give a firm deadline by which you will provide the final report. This information will become visible on the web site as soon as the number is assigned, along with a “to be published by ... ” note.

By submitting a technical report, you provide the University of Cambridge with an unlimited non-exclusive licence to copy and distribute this document forever. In addition, you agree to dedicate the bibliographic metadata related to your report (e.g. publication date, title, names of authors, page count, abstract, notes on the title sheet) to the public domain (CC0 dedication). You also declare that the authors named on the report are the sole copyright holders of this document and that you have obtained any necessary permission from owners of included material. Please take this into consideration if you plan to publish the document later elsewhere. The verso of the title page will carry a copyright notice listing the authors’ names (we can append additional copyright holders to that list, if requested). Also consider, before submitting a report, whether you might want to delay publication because of a patent application.

You may also want to read the usage licence under which we release technical reports at present. This may be updated in future.

Creative Commons licences

[Experimental, work in progress] Funding bodies increasingly require the use of a Creative Commons licence for open-access research outputs, therefore you also have the option to release your report under such a licence. This will be indicated by adding one of these notes (or similar) on the verso of the title page:

Keep in mind that “CC BY 4.0” is a highly permissive licence that allows anyone to remix, transform, and build upon the material for any purpose, even commercially. That's why we have to exclude the University logo found on the cover page. If you have included any third-party copyrighted material in your submission, make sure that you have received permission for their use under your chosen licence. If your report is a long version of a paper submitted to a publisher, please make it clear to the publisher from the initial submission that you intend to release it under a “CC BY 4.0” licence, as suggested by the University's rights retention pilot.


Unless one of the authors is a member of academic staff at the department, you should first seek approval for publishing a technical report from your supervisor (if you are a graduate student) or principal investigator (if you are a research assistant/associate). A PhD thesis approved by the Computer Science Degree Committee is usually automatically eligible to be transformed into a technical report (subject to explicit objections from the Degree Committee). Please wait with submitting your PhD thesis as a technical report until it has shown up in the Computer Science Degree Committee's list of theses recommended for approval.

The technical report editor will normally make no effort to evaluate the quality of the report’s content, but might provide advice if there are obvious stylistic or technical problems with a submitted file. See also the references provided below.

Getting older reports online

Authors of older reports who did not submit an electronic version are still encouraged to do so now, as we want to have as many reports as possible online. For reports that have already been published previously on paper with a Computer Laboratory Technical Report number, the electronic version should preferably be a faithful reproduction of what was published originally and should in particular not introduce changes in the printed page or section numbers.


Technical report numbers do not include a version number. We keep only a single PDF file for each report number. Therefore, in the interest of the archival nature of the collection, any non-trivial change to the content of a technical report, in particular any new scientific contribution, should appear under a new report number.

If the changes are of a rather minor nature, we can replace an old report with a newer version. In this case, the original publication date will remain the same, but the database keeps a list of all update dates and these will appear on the back side of the title page of the updated report. Examples for minor updates include

  • fixed typographical mistakes;
  • fixed technical problems with diagrams or tables;
  • added clarifying footnotes or single sentences;
  • additional or updated references;
  • appending a post scriptum that points out newer work.

Such changes should not substantially alter the content, contribution, or page layout of the original version. Where appropriate, newly added text should be identifiable to the reader as such.

What happens after submission?

Unless we spot a problem with your submission, we aim to make your technical report available online on the Computer Laboratory technical report web page as a PDF file as soon as possible (usually within 1–2 working days of submission), and confirm publication in an email reply.

Check resulting PDF: Once the PDF version is online, check it with multiple PDF viewers (e.g., acroread, okular, evince, firefox, chrome). You may also want to make a test printout. In particular look for:

  • problems with fi or fl ligatures (in the past a common problem with dvips)
  • broken graphics
  • wrong fonts or missing symbols (a sign that not all fonts were embedded in the submitted PDF)

We no longer archive paper copies of new technical reports, as of 2017.

DOI, ISSN, ISBN: We now routinely allocate a Digital Object Identifier for each published report, which links to a web page with the metadata, abstract and download link of the report. The entire Technical Report series has also been allocated an ISSN (actually the print version of it). We do not routinely allocate ISBNs to technical reports, however the department owns a small block of ISBNs, and if requested (usually because of some funding-body requirement), we can allocate an ISBN from that.

Handling of online drafts: If you had an earlier draft of your report on your private web page, you can now remove it and change any links you had to the new URL. When you do this, please do not forget to give the web server an HTTP redirect instruction, such that people who follow links to the removed file will automatically be sent to the current URL. To do this on your departmental home page, put into the file ~/public_html/.htaccess a line of the form

Redirect permanent /~x/y.pdf

Print version: The Library Committee decided that the Technical Report series is, as of January 2002 (report number 527 and higher), primarily an electronic publication. We are no longer routinely producing paper copies. Authors can still ask the librarian to have up to about ten copies of a new report printed and bound (fastback thermal binding in light blue cover pages) by the UIS Printroom. For a larger number of copies, a grant code might be needed. A do-it-yourself plastic-comb binder is available in the department's reprographics room. If you produce a print copy of one of the older reports, you might want to add a new-style titlepage from our file of all title pages.


For any questions on submitting reports, please contact [Javascript required]. If possible, please always mention the relevant report number in the subject line.