Submitting source images for print publication
Continuous tone images (photographs) ▽
Part I — Continuous tone images (photographs)
- Forms of continuous tone images
- Tangible photos: Prints, negatives, transparencies
- Scanned photos
- Digital photographs
- Miscellaneous issues
- Author/editor preferences and restrictions
Part II — Line art and everything else (non-continuous tone)
- Forms of line art and non-continuous tone images
- Illustrations for reproduction with minimal changes
- Tangible sources
- Digital scans, digital files
- Rasterized line art: file resolution and scan settings
- Acceptable file formats for rasterized line art
- Author/editor preferences and restrictions
- Custom maps, charts, and line drawings
General Introduction △
These guidelines concern how to submit existing illustrations (as opposed to new illustrations produced by MetaGlyfix) for print publication in books, journals, annual reports, newsletters, etc., and usually accompanying an author’s manuscript.
[The principles herein are also useful for illustrations intended for screen viewing or web publishing, although certain submission requirements (file resolution and graphic format, e.g.) are considerably less stringent for screen and web.]
Source images generally fall into one of two categories:
- continuous tone images — usually photographs, though sometimes certain art work, such as paintings or raster art created on a computer; continuous tone images have seemingly infinite shades of gray or colors blending into one another
- line art and everything else (non-continuous tone) — maps, sketches, charts, technical drawings, various genres and formats of art, clippings and graphics from previously published works, music notation, hand-written or type-written letters, photocopies, historical documents, software generated graphs, and much more
[To determine when new drawings might be advised, see Scanning originals or drawing anew, and for details about such maps and drawings produced by MetaGlyfix, see Tips for better maps and technical drawings.]
Part I — Continuous tone images (photographs) △
Continuous tone (or, briefly, “contone”) images have seemingly infinite shades of gray or colors blending into one another. Most continuous tone images are photographs, and the two terms will generally be used interchangeably in this section.
An author’s illustrative photographic images might exist in any of the following forms:
- tangible prints, negatives, or transparencies from conventional cameras (which will need to be scanned)
- digital scans of tangible prints, negatives, or transparencies (or even of objects!)
- photos captured by a digital camera
The processes for preparing and submitting photos in the three categories overlap somewhat. All illustrations, whatever their origin, must be digital by the end of the production workflow when files are sent to press. Continuous tone image files, being raster files, must be “high-res” — that is, have a high pixel resolution at printed size — to be accepted and output by printers. Guidance for authors and editors on preparing and submitting the various categories of photo illustrations follow.
Tangible prints, negatives, transparencies △
Clients may submit tangible photos to MetaGlyfix for scanning (either in-house or by a third party). Submit prints or transparencies (slides), positive or negative. Almost any photograph — black and white, color, a slide, a negative, professionally shot, amateurish, old or new, in good condition or bad, cracked or scratched — can be scanned (and restored, if necessary). .
Precautions. Negatives should be protected against scratches. Any photo that has intrinsic value, should be protected as necessary, and MetaGlyfix should be made aware of the special handling and precautions required. In such instances, however, clients are urged to consider scanning the photos themselves or securing scanning services of a reputable local service provider, then submitting the high-resolution scans to MetaGlyfix.
Authors may submit digitized versions of their illustrative photos that they have scanned themselves or had scanned by a local graphic service bureau. They should make sure that the scanned files are:
- of a sufficient pixel resolution for the destination printer and final printed size, and
- saved in an acceptable manner and file format,
as explained below.
Scanning resolution settings for photos △
Scans must be of sufficient resolution — usually measured in pixels per inch (ppi) — for the intended output method (typically an imagesetter) and printed dimensions (width and height in inches, centimeters, etc.). Typically, photo scans and digital photo files must be at least 300 ppi at their final printed size, after any straightening (often necessary) or cropping (sometimes necessary, often desirable).
Pixel resolution and dimensions are interrelated and can be confused. If one scans a 4"-wide photo at a scanner setting of 300 ppi, straightening the resultant digital file might reduce the photo’s usable width to 3.5". Cropping out a background distraction might reduce the width to, say, 3.0". At 300 ppi, 3" would be its maximum width when printed. If the publication’s design calls for photos to be 4" wide on the page, the 3"-wide adjusted scan would become only 225 ppi if enlarged to 4" — (300 ppi x 3") ÷ 4" = 225 ppi — too low a resolution to print. Now, a minimum optimal scanning resolution setting that allows for straightening and cropping can be similarly calculated: (4" ÷ 3") x 300 ppi = 400 ppi. Of course, the calculation is only valid if the person doing the scanning knows exactly how much of any photo will be lost due to straightening or cropping — nearly impossible to know in advance. What to do?
MetaGlyfix can advise about optimal dimensions and scanning resolution settings for each project, and authors and editors are urged to contact MetaGlyfix as well as their publisher before preparing scans.
However, below is a Rough rule of thumb for scanning photos that will work for commonly sized books and journals:
- Assume an image to be 5 inches wide when printed.
- Measure the usable width of the existing photo or transparency, in inches.
- Divide the printed width — 5 inches — by the measured width, and multiply the quotient by 300 ppi; this gives the mininum scanning resolution setting.
- For good measure, multiply the minimum scanning resolution (of the previous step) by 1.5 or 2 for a comfortable scanning resolution setting.
- The resultant file should then be, at minimum, 1,500 pixels wide. If you followed the recommended “good measure,” it would be 2,250 to 3,000 pixels wide, to allow for straightening, cropping, and layout considerations.
Example: The “usable” image in a slide is 2" wide. The minimum scanning resolution setting is calculated as (5 ÷ 2) x 300 = 750 ppi. Multiply the minimum, 750 ppi, by the factor 1.5 to get 1,125 ppi, a scanning resolution setting that allows for straightening or cropping.
Note that the pixel dimensions of a digital file obtained by this rough approach — specifically, the width in pixels — is the same as obtained by the Quick rule of thumb for digital photos for images from digital cameras, below. All continuous tone raster images, whatever their origin, must contain enough pixels to be printed at a desired output size.
For a client — for a non-professional — the critical essential measurement is not the resolution of an image, but its pixel width.
Acceptable file formats for scans △
Save the scan as a TIFF or Photoshop (PSD) file and submit the file only in its unaltered, native graphic format.
- Do not re-save a scanned image as JPEG
- Do not up-sample or down-sample the scanned image
- Do not convert the scanned image to PDF
- Do not embed the scanned image in a word processing or any other document
- Do not embed the scanned image in a MS PowerPoint or other presentation file
Authors commonly submit images captured directly by a digital camera. Occasionally (though less commonly) an author may have photorealistic original art that was created on a computer; the guidelines in this section for submitting digital photos apply equally to original digital art. In either case, the files submitted must be:
- of a sufficient image resolution for the destination printer and final printed size, and
- saved in an acceptable manner and file format,
as explained below.
Digital image pixel dimensions △
Like scans of photos, images from a digital camera must be of sufficient resolution — usually measured in pixels per inch (ppi) — for the intended output method (typically an imagesetter) and printed dimensions (width and height in inches, centimeters, etc.). Pixel resolution and dimensions are interrelated and can be confused.
MetaGlyfix can advise about optimal dimensions and resolution for each project. Authors and editors are urged to consult MetaGlyfix for guidance.
Below is a Quick rule of thumb for digital photos to determine if an image captured by a digital camera has sufficient resolution for printing in a typically sized book or journal:
- Assume the image to be 5 inches wide when printed.
- A continuous-tone raster image should be a minimum of 1,500 pixels wide (the equivalent of 5 inches at 300 ppi).
- For good measure, multiply the minimum by 1.5 to 2.0 (2,250 to 3,000 pixels wide) to allow for straightening and cropping.
All continuous tone raster images, whatever their origin, require the same minimum resolution to be output (printed) by any particular commercial printer or imagesetter. A tangible photo scanned according to the setting calculations described in the Rough rule of thumb for scanning photos in the previous section will have the same pixel width as the digital camera’s minimum width given just above.
Acceptable file formats for images from digital cameras
Submit the digital image only in its unaltered, native format. The preferred format is TIFF or Photoshop (PSD). Most consumer level digital cameras save captured images as JPEGs. JPEG is acceptable as long as the image has never been altered or the file re-saved.
[Why? JPEG is a “lossy” compression format, which means files are made smaller by the elimination of some detail in the image. Every time a JPEG is saved, more detail is lost. JPEGs are good for web publication, but not for print. GIF and PNG are also acceptable for images destined for screen and web, but generally not for print.
- Do not re-save a digital image as JPEG
- Do not up-sample or down-sample the digital image
- Do not convert the digital image to PDF
- Do not embed the image in a word processing or any other document
- Do not embed the image in a MS PowerPoint or other presentation file
Miscellaneous issues △
Photorealistic computer art: Digital files of art created on a computer and designed to be or to resemble continuous tone images can be considered like digital photos in all respects, including calculating file resolution, pixel width, acceptable file formats, and prohibitions.
Resolution: hi-res and lo-res. Imagesetters and most other high-end printed output require high resolution files. However, lower resolution files and prints are perfectly acceptable for estimates, proposals, and layout mockups.
PDFs are acceptable equivalents of prints.
Photos submitted as digital files are acceptable only in standard native graphic formats, specifically as TIFF or Adobe Photoshop (PSD). JPEG format is acceptable for print if it has never been altered or re-saved.
Images embedded in Microsoft PowerPoint files or Microsoft Word documents, or any other word processor document, are unacceptable.
Media or means of transmission: Digital image files may be emailed, transmitted via ftp or a sharing service, or submitted on CD-ROM or DVD. .
Compression: Emailed or ftp files should be stuffed, zipped, or otherwise compressed to prevent file corruption.
Author/editor preferences and restrictions △
The designer may want to crop one or more edges of a photo to enlarge and focus on the subject. If an author or editor has any preferences or restrictions about cropping or any other aspect of treating the photo, please attach a note with the illustration.
(to Part II — Line art and everything else (non-continuous tone))
Last updated 23 June 2018 (Saturday) at 23:33:32 EDT △