American Journal of Physics
Preparing Figures for Publication
The quality of the figures can make or break an AJP article. As you prepare an article
for AJP, consider carefully how best to illustrate it with graphs, line drawings, and/or
photos. Then, after you determine the content of each figure, you can begin working to
prepare it for publication.
Preparing figures for publication demands higher quality and more
attention to detail than, for instance, preparing them for a class handout, a slide
show, or a Web page. To achieve the needed quality, authors must be somewhat familiar
with the technicalities of computer graphics formats and file types.
Bitmap vs. Vector Graphics
Computers can store image data in two fundamentally different ways:
- A bitmap image, also called a
is stored as a rectangular
array of dots or pixels, each with a specific color (or gray level). It therefore
has an inherent width and height, measured in pixels, and if you magnify it enough,
you will see the individual pixels. Nearly all Web images are bitmaps, as
are images made with scanners and digital cameras. For printed materials, however,
it is best to use bitmap images only for photographs and screen captures.
The most familiar file types for bitmap images are Graphics Interchange Format
(.gif), Portable Network Graphics (.png), and Joint Photographic Experts Group
(.jpeg or .jpg); all of these use compression to optimize storage space and
data transmission speeds. For AJP, the preferred bitmap graphics format is
File Format (.tiff or .tif).
- A vector graphic is stored as high-precision numbers and formulas,
so the shapes can be reproduced at any size and resolution. A
has no inherent resolution (in dots per inch or dots per centimeter) and no
inherent pixel dimensions. The resolution of the image you see is therefore
limited only by that of the computer screen or printing press used for output.
Vector graphic formats are best for graphs, line
drawings, and text. For AJP the preferred vector graphic file format is
PostScript (.eps), although
Format (.pdf) is also acceptable
in most cases. Note, however, that both of these file types can also contain
bitmap graphics, so the file type alone is not sufficient to ensure that a
graphic is in vector format.
It's hard to show the difference between bitmap and vector graphics on
a Web page, so please look at this pdf document
to see the difference.
Graphs of formulas or data should ordinarily be plotted inside a frame,
with tick marks around all sides and clear labels on both axes. Be sure to
place labels where they don't cross over any of the plotted data. Also be
careful that numerical axis labels use a consistent number of decimal places
(for example, 0.5, 1.0, 1.5, 2.0; not 0.5, 1, 1.5, 2).
There are many software environments that can produce publication-quality
graphs, including commercial packages such as
as well as open-source software such as
All of these can save graphs in AJP's preferred format, Encapsulated PostScript
(.eps). The most ubiquitous plotting software, of course, is the spreadsheet
program Excel. While it can sometimes work in a pinch, we do not recommend
Excel because it is not designed for scientific plotting and it cannot save
directly to .eps format.
Whatever software you use, your final graph should be a vector graphic,
not a bitmap (see above). The preferred file type is .eps, although .pdf
is usually an acceptable substitute. On rare occasions, a graph
might be so complex that a vector format is impractical; you may then
submit it as a bitmap .tiff image, but the resolution must be approximately
600 dots per inch at the final printed size (that is, about 2000 pixels across
if it is to be printed one column wide).
Line drawings, like graphs, should be created as vector graphics, not bitmaps,
and saved in .eps format if possible, or .pdf if necessary. The most commonly
used software for line drawings in the publication industry is
An open-source alternative is Inkscape.
We do not recommend PowerPoint for
creating publication-quality line drawings. (Again, on rare occasions when
a vector format is impractical, a .tiff image is acceptable if its resolution
is approximately 600 dots per inch.)
Be sure to compose and crop your photographs to make their essential features
clear. Also be sure to make a test print on a black-and-white
printer, at the final printed size, to check the brightness and contrast; this
step is especially important for color photos.
Unlike graphs and line drawings, photographs are best submitted as bitmap
images in .tiff format. The resolution should be approximately 300 dots per inch
at its final printed size (that is, about 1000 pixels across if it is to be
printed one column wide). Most image editing software can convert other
bitmap formats to .tiff.
For your initial submission, it's usually best to create a lower-resolution
.jpg version of your photo, with moderate compression. This will result in a much
smaller file size when you incorporate the figure into your manuscript.
Also, unfortunately, LaTeX cannot import .tiff images.
Just be sure to save a high-resolution, uncompressed "master" version of your
photo in .tiff format, and submit that for production when requested.
If you need to annotate a photo with text, it's best to import it into
a graphics editing program like Adobe Illustrator and do the annotations there.
Save the resulting image in .eps format. Then the photo will still be a bitmap,
but the annotations will be resolution-independent vector graphic elements.
Whatever you do, don't open compressed .jpg images and edit them repeatedly.
The .jpg format uses lossy compression, so each open/save sequence will reduce
the quality. Again, it's best to save the original image as a .tiff.
In articles that are about computer systems, it's often helpful to include
illustrations made from screen captures. These images are inherently bitmaps
and usually have rather low resolution. Please leave the resolution unchanged
(that is, don't resample the images), and convert them to .tiff format. For
your initial submission, the best format is usually .png (incorporated into
your .pdf manuscript as with any other figure). You should never convert
a screen capture to .jpg format, due to the lossy compression.
Fonts and Text Labels
Fonts used to label figures must be easy to read, appropriately sized, and
consistent. When saving a figure as a vector graphic, be sure to tell your
software to embed the fonts in the file. Even then, try to avoid using
nonstandard fonts. Sometimes it's best to convert the fonts into outlines,
if your software offers this option.
Capitalize the first word of each text label, but for a multi-word label,
capitalize only the first word and any proper nouns (as in an ordinary sentence).
Initial Submissions vs. Production Quality
When you initially submit your manuscript to AJP, it should be a single .pdf file
incorporating all figures. Each figure should preferably appear near where it is
first referenced—not at the end of the manuscript.
To facilitate the reviewing process, we prefer that your initial .pdf
submission be no larger than 1 MB if at all possible.
In order to limit the file size, you may
need to use lower-quality versions of figures in your initial submission. This
is fine so long as the content of the figures is still clear.
If and when your manuscript is conditionally accepted for publication, the
editor will ask you to submit an editable manuscript (preferably LaTeX, but
optionally MSWord), along with publication-quality figures that are each in
a separate file. This is when you should submit your highest
quality figures, using the formats recommended above. Name each figure
file in the format "AuthorNameFig01.eps" or "AuthorNameFig02.tiff." Please package
the manuscript and figure files into a single .zip archive for submission.
Most figures in AJP are printed at a width of one text column, about 3.4 inches
(8.6 cm). When necessary, a wide figure can be printed across both columns.
Try to design your figures with one or the other of these widths in mind,
choosing the layout, font sizes, and line weights accordingly. Be sure to make
a test print of each figure at its final size to check these details. Often a
figure that looks great on a computer screen will have flaws that are obvious
when it is printed.
A figure may be divided into parts, labeled (a), (b), and so on. Usually it is
best to combine the multiple parts, including the labels, into a single figure
file. Alternatively, you may (in your editable package for production) submit
multiple figure parts as separate files, with names of the form AuthorNameFig01a.eps,
AuthorNameFig01b.eps, etc. Always think carefully about how you would like
the figure parts to be arranged on the page, and whether the combined figure
is to be printed at a width of one column or two.
Color in Figures
AJP encourages the use of color to enhance the clarity and aesthetic appeal
of figures. All figures submitted in color will appear in color in the online
version of AJP.
However, the printed version of AJP ordinarily does not use
color for figures, while some AJP readers will make personal copies of your
article using a black-and-white copier or printer. AJP therefore
discourages the use of color to convey essential information that would not
be apparent in a black-and-white version of a figure. For example, in a graph
showing multiple curves within the same frame, you should ordinarily distinguish the
curves with different dashing patterns. Distinguishing them by color as well
is then a nice touch, but not essential for the reader's understanding.
Similarly, the caption of a color figure, and any other text that refers
to it, should not refer in any essential
way to the colors used in the figure. So, for example, your caption should
refer to different lines on a graph by their dashing patterns (or perhaps
line weights or gray levels or locations), not by their colors. When appropriate, you may
include a parenthetical "(color online)" in the figure caption, just to let
readers know that the online version is prettier.
Be sure to make a test print of each figure on a black-and-white printer,
to check that all the essential information is preserved.
If the use of color in a figure is essential to the content of an article, then
authors may pay to have the figure printed in color. Color printing
is expensive. The current rates are:
- $650 for the first figure;
- $325 for each additional figure.
In this case, it's fine—and probably necessary—to refer to the colors
in the figure caption. Please let the editors know as early as possible if it
is your intent to have a figure printed in color. Unless we hear otherwise,
we will assume that all figures will be printed in black and white.