Images
All images should be CMYK (not RGB, Indexed colour or LAB) unless using spot colours in Photoshop DCS2 format. They should be scanned or created at the size they are going to be used and at an appropriate resolution:
- Colour images: 300dpi (Saving colour images at higher resolutions will make no difference to the printed quality and will take longer to process, slowing down the job). The exception to this is when you have an image that contains small text, in this case it is worth scanning or creating the image at 600dpi. If you have already got a 300dpi image that has small text in it and you change the resolution to 600dpi the image quality will not increase, it must be originated in this way to benefit from the resolution enhancements.
- Images saved from web pages in most cases are 72dpi and will not produce a high quality result.
- Bitmap/Lineart images (pure black and white): 1200dpi
- Greyscale images: 300dpi
- Colour images: 300dpi
When saving individual images, these are some of the image file formats you will come across:
- TIFF - Retains quality when compressed. Excellent format.
- EPS - Excellent quality format and allows additional information such as cut-out paths.
- JPEG - Great for small file sizes, but the quality of the image will degrade in proportion to compression. This is also true if JPEG compression is used to compress an EPS file.
- PSD - Photoshop native format. It is advisable to save a copy as a TIFF and use this instead.
- GIF - Internet standard. Uses a limited colour palette so it is not advisable to use this.
- BMP - Windows standard. Retains image quality but file sizes can be large.
