Acquiring images
Soft or in focus
Many of the images we started with vary for a number of reasons:
- They were a copy of a copy
- They were a photograph of a photograph
- Photography was in it’s infancy
- They were enlarged
- They were not in focus
- They were not consistently exposed
- They were a small print from a large negative or plate
With the exception of the last attribute, most images have limitations in terms of what you can do with them. For example to a limited degree you can focus something that is out of focus, but it will also affect other areas of the image that should be out of focus.
Capture
Where possible acquire the original image and scan this at a moderately high resolution depending on the size. This is the raw image. In exceptional cases where the source is very high quality and carries a lot of detail scan at 2400 dpi (Dots per Inch) or above for archival purposes.
Aim to capture the image in either a TIFF, or BMP format, or JPG with no compression. If it is possible to scan at higher than 24 bit resolution (8 bits per colour) then do so particularly where the image is quite dark lacking in pale colours or shades, or quite light lacking in dark colours or shades and is also a detailed image.
Use the longest side of the photograph as a guide for what scanning resolution you would need to scan at.
| inches | mm | Scanning Resolution (dpi) |
| 1″ | 25mm | 1200 |
| 2″ | 50mm | 1200 |
| 3″ | 75mm | 1200 |
| 4″ | 100mm | 600 |
| 5″ | 125mm | 600 |
| 6″ | 150mm | 600 |
| 8″ | 200mm | 600 |
| 10″ | 250mm | 300 |
| 12″ | 300mm | 300 |
Storing the image
We need to have an agreed process for naming and cataloguing images (tbd) to ensure that they remain useful for the future. The file name will always be the key. Further information may be held in an internal or external database based on the file name. Within wordpress we can add this information against the uploaded file. Make a note of any of the following details when you scan the image for later processing.
- File name
- Approximate Date of the image
- What is the image of
- Any notable people or events in the image
- Where the image came from
- Any restrictions on what we can do with the image
- Who owns the original image
- Who scanned the image
- When it was scanned
Images can be stored on a laptop or personal computer at the time they were recorded. It is important that the images are removed and passed to the next stage when they are no longer required on the personal computer as the arrangement with the source provider is to provide images to Prestwood Archive and their representatives (volunteers), and not to individuals for personal use.
Processing stage 1
The following steps can be taken anywhere, they do not have to be taken at the time the image was acquired.
It is unlikely that any raw scanned images can be placed on the website unedited. In general and based on the initial experience of scanning the first 29 images the following can be done to improve them. Note that some of these steps may not be possible on all image editing software, so some thought needs to be taken in terms of what is practically possible. In my case I used Adobe Photoshop CS6 (full version).
Do the following:
- Crop the image to suit the image content
- Adjust the brightness and contrast
- Adjust the levels of the exposure. (this has the effect of ensuring that the brightest shades map to the lightest shade in the range, and the darkest shades map to the darkest shades in the range.)
- Convert to black and white (optional; in my experience the colour caste on the images often detracted from the original image).
- Selectively darken or lighten areas of inconsistent exposure (optional)
- Remove any “blobs” dust or dirt (optional) with a cloning brush.
- Repair any damage to the image using the clone brush (optional)
- Resize the image to 1600 pixels in longest axis unless scaling to this size will lose a lot of detail. (We do need to strike a balance between storage space required for images and the required resolution).
This gives us a master image for the Prestwood Archive. This needs to be saved independently of the website on a storage device. The information that was collected at the time also needs to be saved in a spreadsheet accompanying the library where the images are stored.
Processing the image stage 2
Web preparation
Taking a prepared master image from the Prestwood Archive resize the image so that the x dimension is no larger than 600 pixels wide. Rename the file by appending “-web” on the end of the file name. Save the image as a progressive JPG with compression set to around 70%. This will provide a relatively small image which can be downloaded from the web quickly and is ideal for viewing on a computer screen.
Upload the file to the website bearing in mind that the copy needs to be placed within the appropriate website, there are seven of them. Login to the site, go to the media library and upload the image. Within the form for the image you can summarise the notes that were taken when the image was acquired, they will then be available to the editor.
This completes the scanning process. See this page for some examples of how an image can be improved.
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