Export image size for publication

[dev2217]

Hi,

I need to send few of my images to a book publishing company and would like to know the optimum image quality for publication.

My picture dimensions are 4928x3264  or 3264 x 4928 and shot in JPG high resolution.

While exporting I selected the image size as the above and given the resolution as 320 ppi.

I would like to know whether the above ppi ca give the best maximum quality on the printing . ( Publication photo sizes are may be 4x8 inches or 10 x8 inches or less)

your reply  to solve the above problem would be appreciated.

Thanks

dev

[Per Berntsen · Accepted solution]

The relationship between pixel dimensions and print size is as follows:

Pixel dimensons divided by ppi equals print dimensions (in inches).

So a 4928 x 3264 image printed at 320 ppi will be 15.4 x 10.2 inches.

If you don't know the exact size the images will be printed, it is probably best to send the full resolution file, and leave resizing to the publishing company.

Also bear in mind that the images will have to be cropped to fit the print sizes you mention, since they have a different aspect ratio than the originals. 4 x 8 has an aspect ratio of 1:2, 8 x 10 has an aspect ratio of 4:5, and your images are roughly 2:3.

[Abambo]

The most confusing parameter in the publishing world is always the ppi parameter. The ppi parameter is important for a given size in inches for reproduction purpose (publisher's view). An image at the same pixel resolution will have a higher ppi for a smaller size in inches/cm. Commercial printers require normally pictures between 300-400 dpi (ppi). My preferred printing provider issues a warning, when images have less than 240 dpi.

From the view of the photographer, there is only the resolution of your camera or the crop you produce during editing important, as that is the maximal resolution available.

The only reasons for a photographer to reduce the image size (pixels) is, when the resolution is to high on the recipient's side for further transformation and/or when you do not want to send over a full resolution picture for your ip protection.

Downsizing does not affect negatively the picture. In the contrary: Slightly out of the focus pictures may appear sharper.

Up-scaling however impacts the picture quality, because the scaling algorithm needs to create information that is missing. If the algorithm is a good one, it does that by preserving image sharpness.

This is for the introduction.

Now the concrete answer to your problem is the following: Ask the publisher how they need the pictures. Very often, publishers give very precise information on how they want the pictures. If such instructions are missing, send the best quality available. High resolution JPEG files that do not need much adjustments are in a good quality at 2-4 Mb.

When I need sending images for publishing, I create cropped (my point of view, but I allow for enough image material around the centre of interest) images of up to 2.5 Mb. When sending by e-mail, I try not do send e-mails with a total size of much more then 10Mb.

(We cape at 40Mb on output and 20Mb on input).