Guidelines for Preparing Digital Image Files for Online-Only Journals

Resolution: Before capturing the image you must consider the following: Final required resolution, original size of the artwork, and finished size. You can then apply these values to a formula to achieve proper resolution. The scaling of the artwork must also be considered in the formula. Divide the finished size by the original size to get a scaling factor. Therefore, to capture the right amount of data use the resolution rule: Color and grayscale scan resolution = 150 × Scaling factor. For black and white bitmap, scan resolution = 300 × Scaling factor. The table below shows recommended resolutions for different images. Images of higher resolution are acceptable but images of lower resolution are unacceptable.

Color Space: All work submitted as digital color should be in the CMYK (Cyan/Magenta/Yellow/Black) mode or RGB (Red/Green/Blue). Authors must ensure that color saturation and color balance are correct before sending files. Most desktop scanners, digital cameras, and video capture systems save files as RGB. Do not send files as Indexed, Lab, or Duotone color mode.

File Format: Use EPS or TIFF format. Although there are many graphic file formats to choose from, it is safest when printing to a PostScript device to use EPS for vector graphics and TIFF for raster/bitmap graphics. Vector graphics are object-oriented files, which contain drawing instructions, in applications such as Illustrator® or Freehand®. Fonts in these EPS files should be converted to "create outlines" or "convert to paths" as this will eliminate the need to download the fonts for outputting. Raster graphics are bitmapped files such as scans or screen shots. When using TIFF files be sure to have the correct amount of data in the file for the line screen to which you are printing. Use an image-editing program such as Photoshop® to rotate the TIFF, then bring it into your page as a "straight" image.1 Don't rotate TIFFs within a page layout application, for example when combining figure parts, as the printer will have to recalculate new positions for each pixel. Also crop graphics closely with no unnecessary white borders beyond actual image to help control accurate placement and file sizes; do not include captions or figure numbers within the image.

Proof: Always supply hard copy produced from the digital files being submitted. This provides a double check of the proper image. In the event that the digital file cannot be accessed, we will scan your proof so no delay is encountered in your deadline. Please supply overlay/description of areas of focus and critical color concerns.

Media and Compression: Some compressed files are acceptable, including LZW, Unix or PK-zip on 3.5" Iomega® ZipTM 100 MB + 250 MB or CD (Mac or ISO 9660 format) only.

Summary of digital image specifications for various types of figures. Type Format Mode Resolution Density/Dot Black & White line Eps Vector n/a 0% or 100% art Tiff/Eps Bitmap (1 bit) 300 dpi Halftone Tiff/Eps Grayscale 150 dpi 2-98% Combo (image + Tiff/Eps Grayscale 150 dpi 2-98% type/line art) Color Tiff/Eps CMYK 150 dpi Total color saturation = 320%

1 Mention of trade names is for descriptive purposes only. No endorsement of these products by the publisher is intended, nor is any criticism implied of similar products not mentioned.