Guide to preparing final artwork

Information Sheets for Downloading

• Producing production-quality artwork (after acceptance) (doc 43KB)

See the full list of information sheets.

This guide is only for authors whose manuscripts have been accepted in principle, and who have been asked by the editor for production-quality artwork. Please prepare your artwork using these guidelines so that it will be processed as quickly and smoothly as possible, and give the best possible results in the final printed version.

Please follow these instructions carefully.

When preparing figures, authors are advised to refer to printed copies of Nature to get a sense of general size and style points. All digital images should also comply with the Nature guide to digital images.

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Table of contents:

• 1. Introduction
• 2. Disk formats and labelling
• 3. Hard copy artwork
• 4. Presentation of figures, sizes and lettering
• 4.1 Lettering
• 4.2 Sizing
• 4.3 Arrangement of parts
• 5. Electronic file formats
• 5.1 Acceptable electronic formats
• 5.2 Image types
• 5.3 Notes on particular formats and file conversion
• 5.4 Converting to postscript
• 6. Colour artwork

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1. Introduction

At Nature we use electronic artwork to improve the quality of figures on the printed page. However, electronic files do not always work perfectly. If they are not in a suitable format, this could lead to delays in processing or poor reproduction in the journal. Hence, we also need a high-quality printed copy of each figure to see exactly what should appear in print, to match the colour, check file conversion, and make a high-quality scan if we cannot use an author's electronic file.

When you send us your final artwork files, please include the email address of a person (an author or author's artist) who can promptly deal with our artwork format queries over a three-week period after your paper is accepted for publication.

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2. Disk formats, labelling and file names

Figures must be sent on disk, in one of the following PC or Mac formats:

• Floppy
• Zip (100MB or 250MB)
• CD-ROM

We are unable to accept final submissions by e-mail, ftp, ISDN or online.

Disks should be labelled clearly with a list of the files they contain; the software used to create the images and their formats; corresponding author name; and manuscript number. When naming electronic files, use the figure number and a file extension (.EPS, .TIFF, .PSD) to indicate format used (for example, C12345BFig1.EPS).

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3. Hard copy artwork

Hard copy artwork should be the highest quality printout you can achieve, as it may have to be scanned for publication if we cannot use the electronic version. Label each copy on the back with the corresponding author's name, manuscript number and figure number.

If any figures consist of a number of panels, please include a hard-copy of each composite showing how the panels should be arranged within each figure, reduced to the minimum size you consider possible for each composite. Indicate whether it is essential for parts to be in the alignment shown (for example, if horizontal or vertical arrangement is essential for comparison) or at particular spacings (for example stereo pairs).

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4. Presentation of figures (electronic and hard copy)

4.1 Lettering

Lettering should be in a sans-serif typeface, preferably Helvetica or Arial, the same font throughout all figures in the paper to reduce the need for us to re-letter. Units, capitalization, etc. should follow Nature style (see formatting guide), and refer to recent issues of the journal published after 19 May 2005). Where practical, avoid placing lettering directly over images or shaded areas, as this can cause problems where editing or re-lettering is needed. Separate panels in multi-part figures should each be labelled with bold, upright (not italic) a, b, c... Amino-acid sequences should be presented in one-letter code in Courier. Authors who do not have access to Courier or other monospaced font.

Please bear in mind that it is much easier for our art department to process your artwork if you can avoid having varied formats within one figure. A composite figure containing panels with line graphs, gels and half-tone photographs takes more time to process than a figure whose components are similar in format. Similarly, the layout of your article is simpler and more likely to be attractive if you minimize the number of panels per figure composite.

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4.2 Sizing

Nature will often reduce figures to the smallest size possible for reasons of space. Authors are encouraged to indicate the smallest possible size they think appropriate for their figures, but Nature reserves the right to make the final decision.

For guidance, Nature's standard figure sizes are 89mm, 120mm, 136mm, 183mm wide. The full depth of a Nature page is 247mm.

Authors should check (using a reducing photocopier) that, at the smallest possible size, lettering remains readable and lines are sufficiently (but not too) heavy to print clearly. We recommend that type is between 6 and 8 point, and lines between 0.5 and 1 point (lines thinner than 0.3 point may vanish in print) at the final, reduced size.

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4.3 Arrangement of parts

Nature will be guided by the authors' suggested layout of parts within figures, but may rearrange parts if necessary. Authors should indicate essential layout features, for example particular alignments of panels within a figure. We value clear instructions from authors to help us lay out their figures.

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5. Electronic image formats

Please note that Nature does re-letter and re-size artwork, so we need to manipulate it electronically. If authors supply artwork in 'uneditable' formats, publication is likely to be delayed. If you cannot provide artwork in our preferred formats as described below, or have difficulty in understanding our requirements please contact our art editors so we can advise you as to how best to prepare your artwork in a compatible format.

For print production, the range of usable electronic formats is limited, and there are particular technical issues that need to be considered when preparing artwork for print. We therefore ask authors to try to provide their figures in our preferred formats if possible, and to contact us if there is a problem, rather than sending us artwork in a format not on our list.

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5.1 Acceptable electronic formats

Nature preferred formats are:

• Adobe Photoshop or TIFF format (high resolution, 300-600 DPI) for photographic images
• Adobe Illustrator, Postscript, EPS or PDF format for figures containing line drawings and graphs, including figures combining text and line art with photographs or scans.

If these formats are not possible, we can also accept the following formats:

• JPEG (high-resolution, 300-600 DPI)
• Canvas (version 3.5 to version 7)
• Freehand (up to version 8)
• CorelDraw (up to version 8)
• Microsoft Word
• Microsoft Excel
• Microsoft PowerPoint (only if used as described in 5.3 below)

Please do not send the following formats, as we cannot use them:

• Canvas before version 3.5
• DeltaGraph
• Tex
• ChemDraw
• SigmaPlot

In these cases, files should be converted to postscript, EPS or PDF format or contact us for advice.

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5.2. Image types

The best format for any particular figure depends partly on what sort of images it contains. Images fall into two basic categories: rasterized images (also called bitmapped images) and line (or vector) art.

Rasterized (or bitmapped) formats such as TIFF and JPEG are composed of an array of dots, or pixels. The image quality is determined by the resolution, usually measured in pixels (dots) per inch (DPI). For printing, we need a minimum of 300 DPI at the size the image is to appear on the page. We prefer 400 DPI if the figure contains text, and 600 DPI where it contains small text or other fine detail.

Size and resolution are linked so that, for example, enlarging an image to twice its original size will halve the resolution. If the resolution is too low, individual pixels become visible to the eye, and the edges of lines begin to appear 'stepped' and the image may lose its sharpness.

Vector (or line-art) formats such as Postscript, EPS and PDF preserve individual lines and text as separate, editable components. This makes them easier and quicker to re-letter or edit as necessary and gives sharper results in print and online. Also, because these images have no 'resolution' as such, they may be enlarged without any reduction in quality.

In general rasterized formats are best suited to photographs and scans, and to composite figures containing photographic or scanned images with minimal or relatively simple labelling. Line or vector formats are best for graphs and schematic diagrams, and for composite figures containing a mixture of photographs or scans and detailed text or line artwork.

Please note that for composite figures containing a mixture of rasterized images and line art, the resolution of any rasterized images must be sufficiently high - that is, 300-600 DPI at the final printed size.

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5.3 Notes on particular formats and file conversion

In Photoshop, it is possible to create images with separate components on different layers. This is particularly useful for placing text labels or arrows over an image, as it allows them to be edited later. If you have done this, please send the Photoshop file (.psd) with the layers intact.

Although PowerPoint can export JPEG format, the resulting files are low resolution and not suitable for printing. The only way to obtain sufficiently high-quality graphics format from Microsoft Office documents is to generate Postscript using 'Print to file', as described below (Section 5.4).

JPEG is a compressed format which achieves smaller file sizes by discarding information. As a result, saving in JPEG format may cause a noticeable reduction in quality, so we prefer Photoshop or TIFF format for rasterized images. Where JPEG is the only option available, the quality should be set to the highest possible to minimize loss of information. TIFF files are larger than JPEGs, but it is possible to reduce the file size by saving with compression (LZW compression is preferred), which does not degrade the quality of the image.

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5.4 Converting to Postscript

Print to file If you have a postscript printer driver installed, a useful way to create high-quality graphics files (particularly line art and graphs) from non-standard software is to generate Postscript using 'Print to file'. To do this, open the image in its native application, go into the 'Print' menu and change the destination from 'Printer' to 'File' (or click on 'Print to file'). This will write a Postscript (.ps or .prn) file, which could be opened in various graphics packages and saved as an EPS file, or could be converted to PDF format using Acrobat Distiller.

If you do not have the necessary software to convert the Postscript to EPS or PDF format, please send us the plain Postscript file or contact us for help.

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6. Colour artwork

Colour artwork must be provided in CMYK format.

When preparing electronic figures for print, colour requires particular attention - particularly where small colour variations might be critical to the interpretation of the figure. Computer screens display colours using red, green and blue pixels (RGB), whereas the four-colour printing process uses inks in cyan, magenta, yellow and black (CMYK). Therefore, colour figures supplied in RGB mode must be converted to CMYK in preparation for printing.

However, the range of colours that can be achieved in CMYK is limited, so converting from RGB to CMYK often affects the appearance of images. In particular, brighter colours are likely to appear muted, and the contrast between different coloured areas may be reduced.

Although we can easily carry out the conversion from RGB to CMYK at Nature, we prefer authors to do this before submitting their figures, so that they can see how the colours will be affected and, if necessary, make adjustments to ensure that no important detail is lost.

Please note that if you have created images with layers in Photoshop, then on converting from RGB to CMYK, Photoshop will recommend 'flattening' the image (that is, combining the layers into one single image, so that individual parts can no longer be edited independently). At Nature, we prefer to work with the editable layers. Therefore, either compose the layers with images already converted to CMYK, or check that the colour conversion is acceptable but supply the original RGB file with layers so that we can carry out the conversion to CMYK after editing.

Finally, different computer screens have different settings for colour, brightness and contrast, so even where images are supplied in CMYK it is important that we have a good-quality printed hard copy for reference and colour matching.

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