Planning a history #3: Images
This is the final of three articles about planning and preparing a history of your organisation. This post focusses on sourcing, managing, and preparing images.
In a history, images are a major area that should not be left until last minute to be organised.
Being a history, you may find that you have to accept less than perfect images because a poor quality photograph is the only one available to show a particular part of your story.
However, there is an important distinction to make when talking about image quality: We should distinguish between poor quality old and/or damaged images and poor quality due to bad reproductions of old images.
Old or damaged photographs we often have to accept in a history because that is all that's available.
Poor reproductions of old images can usually be overcome by requesting the correct file size from the person or organisation supplying your images, or by scanning your hardcopy prints to the correct size.
A (very) rough guide to photo sizes
Image quality is measured in DPI (dots per inch). For most commercial printers, a minimum of 300 DPI is required to reproduce photos to their best quality.
Note: You can get away with a lower DPI count with digital printing, but for the purposes of this article, I'm going with industry standards that ensure you get the best quality.
If you wish to reproduce an image at 10x6cm in your book, then your photo will need to be 300 DPI in those dimensions of 10x6cm. Knowing the dimensions is important, because you will be able to print this image smaller than 10x6cm, but you would not be able to make it larger without a loss of print quality.
If you need a full magazine-page size image (roughly A4), then you should ensure that the image you source is 300 DPI at A4 size.
On a mac, the easiest way to find and adjust the resolution of your image is to open the photo in Preview. Then under Tools, click on Adjust size and you will see the dimensions and resolution listed.
If the resolution is showing as, for example, 72 DPI, you can change that by unchecking the Resample image box and changing the resolution to 300 pixels/inch.
When you make this change you'll see that the width and height dimensions have become smaller to suit the new resolution. You will now be able to tell if you have the correct size photograph for high-quality printing.
Note the inverse relationship here between resolution and dimensions:
- As you increase resolution, the width and height decreases
- As you decrease resolution, the width and height increases
Image files types
There are many files types, but I will focus on the main three that 80% of clients find they have: RAW, TIFF and JPG.
With digital image files .RAW is the gold standard. If your photographs have been provided by a professional photographer, then they will most likely have shot in RAW. However, you should confirm this will be the case when briefing the photographer.
At the end of the shoot, ensure you get a copy of the RAW files for your archives. They will be useful if you wish to zoom in on particular details on a large image.
That being said, for most publishing purposes .tiff files will do the job very well and may be all you have access to if you haven't employed a professional photographer.
If a tiff format is not available, then jpeg / jpg may still be used.
Note: tiff files will be much larger than jpegs.
If you are scanning images yourself, then ensure that you scan images to the correct size for printing purposes, as discussed above.
A rule I always use is to scan images to the largest possible size and save them in tiff format. On most recent model scanners you will be able to go up 900 DPI but possibly as high as 1200 DPI. By scanning to this size, if you are unsure how large an image will be reproduced you will give yourself the scope to adjust the image size and still end up with a 300 DPI quality when cropped.
If you are requesting or purchasing images from a photo library, or from institutions such as Trove, a State Library, the National Library of Australia, or the Australian War Memorial, always opt for the largest file size.
If you plan to use an image for commercial purposes, that is, in a book you are going to sell, then you must ensure that you have the right to use the images. It is usually not legal to simply pull photographs off the internet and reproduce them in your book.
If you do find images online, then you should seek permission from the image owner. You will most likely need to request a print quality version of the image anyway as internet images are usually 72 DPI – so not suitable for printing anyway!
I hope you have found this series of posts useful.
If you are planning a history and would like a advice on how to proceed, I'm more than happy to present to your planning committee. Please contact me, David Longfield, at email@example.com.