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Creating Images

What...diskimage.png

Digital images can be categorised into two areas: raster images and vector images. Raster images are based on describing the location and colour of pixels and are synonymous with continuous tone images such as photographs or scans. By contrast, vector images are based on mathematical instructions and lend themselves to defined lines, curves, shapes, logos, cartoons, fonts and technical drawings.

Why...

It is important to understand how to create high-quality images so that they are flexible in how they can be used. An archive such as the Modern Records Centre will prefer high-quality images that preserve the original detail. This will ensure that the authenticity and reliability of the image is preserved as best as possible.

The Modern Records Centre recommends the use of uncompressed TIFF for your master raster images and either JPEG or PNG as your delivery raster format. We recommend the use of SVG as your master and delivery vector image format.

How...

Images taken with a digital camera (raster)

Typically images taken with a digital camera can be exported in few ways; as the RAW data file, an in-camera processed TIFF or as an in-camera processed JPEG file.

Exported File Format from Camera Notes
Raw Image Data File (RAW)

The RAW data file is an unprocessed 'digital negative'. It retains all captured data without interpretation and requires processing and optimisation prior to delivery. The RAW format generated by a digital camera is proprietary to the camera manufacturer

Tagged Image File Format (.tif) A TIFF will either be uncompressed or compressed. An uncompressed TIFF will retain the original detail but because it has received in-camera processing it will not retain the exact data as captured by the light sensitive chip. A compressed TIFF will sacrifice detail as a result of the compression process.
Joint Photographic Experts Group JPEG Interchange Format File (lossy compression) (.jpg) The JPEG is a compressed file which has undergone lossy compression. This means that detail will have been sacrificed during the compression process. You will be able to convert a JPEG to a TIFF but you will not retrieve the data sacrificed during the JPEG compression process.


If you are likely to deposit your images with an archive such as The Modern Records Centre we recommend the following...

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  • Capture your image at the highest possible quality - a minimum pixel array of 1,600 x 1,200 pixels should be used
  • Export either the in-camera processed, uncompressed TIFF, or the RAW file format.
  • If processing the RAW file...
    • Maintain the original spatial resolution
    • Set the colour resolution/bit depth (the number of colours or brightness which are available to represent the colours or shades of grey in the original image) at 24 bits (8 bits per channel) for colour images or 8 bit grayscale for black & white images.
    • Set the colour space (the colour space that allows for the reproducible representation of colours) to Adobe RGB (1998).
    • Save the file as an uncompressed TIFF, version 6.0.
  • If required, produce a smaller file for sharing, potentially at a lower 150 ppi/dpi depending on the end-usage requirements. A JPEG file or Portable Network Graphics (PNG) (.png) file will be suitable for this.

Scanned images (raster)

If you are scanning material in order to deposit with an archive such as the Modern Records Centre we recommend, as a minimum, the following...

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Text or graphical documents (minimum)
  • Set the spatial resolution to 300 ppi/dpi (the frequency at which samples are taken by the camera; measured in ppi/dpi).
  • Set the colour resolution/bit depth at 24 bits (8 bits per channel).
  • Embed the colour space as Adobe RGB (1998).
  • Save as an uncompressed TIFF, version 6.0.
  • Produce a smaller file for sharing, potentially at a lower 150 ppi/dpi depending on the end-usage requirements. A JPEG file or Portable Network Graphics (PNG) (.png) file will be suitable for this.
Photographs (minimum)
  • Set the spatial resolution to 600 ppi/dpi.
  • Set the colour resolution/bit depth at 24 bits (8 bits per channel).
  • Embed the colour space as Adobe RGB (1998).
  • Save as an uncompressed TIFF, version 6.0.
  • Produce a smaller file for sharing, potentially at a lower 150 ppi/dpi depending on the end-usage requirements. A JPEG file or Portable Network Graphics (PNG) (.png) file will be suitable for this.
Transparencies (slides/negatives) (minimum)
  • Set the spatial resolution to 2400 ppi/dpi.
  • Set the colour resolution/bit depth at 24 bits (8 bits per channel).
  • Embed the colour space as Adobe RGB (1998).
  • Save as an uncompressed TIFF, version 6.0.
  • Produce a smaller file for sharing, potentially at a lower 150 ppi/dpi depending on the end-usage requirements. A JPEG file or Portable Network Graphics (PNG) (.png) file will be suitable for this.

Vector images

If you are creating vector images for deposit within an archive such as the Modern Records Centre, we recommend the following...

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  • Export as a Scalable Vector Graphics File (.svg).


Tick image - Public Domain