Colour and digital file information

What colour profile and file size, format and at what dpi should I use for a certain size print? We know it can be confusing at times – that's why we've put together this handy guide of colour and digital file size information for photographic prints.

Colour Profiles

Our choice of colour profile for the best possible photographic printing with our very carefully controlled ICC workflow is Adobe RGB (1998). We do accept files in other colour profiles but these must be converted to Adobe RGB (1998) before printing on either the Lambda or Giclée printers. If you prefer you can change your colour to Adobe RGB (1998) before sending it to us. That way (if your monitor is properly calibrated) you will be able to see any colour shift or variation and can adjust it before we receive the files or leave it as is and we can adjust it for you. If you are sending us files for standard Digital Machine Prints the colour profile is standard sRGB.

You can also download our Lambda Colour Printer profile to see a fairly accurate preview of the printed output on your screen (if your monitor is properly calibrated). We calibrate our Lambda Colour Profile frequently so please download the latest version from the link above.

After downloading the profile (Lambda_10_10_08.icc) simply drop it into the following folder on your mac – / Library / ColorSync / Profiles folder or the / Users / username / Library / ColorSync / Profiles folder. Then restart Photoshop, open your image and choose from the top menu Edit > Assign Profile. In the dialogue box that appears select the Lambda profile from the Profile drop menu. This temporarily assigns the Lambda profile to the image without converting colours to the profile space. You can permanently assign the Lambda Profile to your image by choosing from the top menu Edit > Convert to Profile and then from the dialogue box that appears choose the Lambda Profile from the Destination Space Profile drop menu.

For PC users the path to place the Lambda profile in is WINDOWS \ system32 \ spool \ drivers \ colour folder.

If you have any questions about colour profiles please feel free to call and one of our friendly and knowledgeable staff will be pleased to help you.

File Formats

As a general guide for colour prints on either our Giclée or Lambda printers, your images should be in RGB, any layers flattened and preferably saved as a Tiff file (.tif) with LZW compression. This will maximize the quality of your image and also keep the file size down. Other file formats are acceptable such as a layered tiff or photoshop document (.psd) but these will have an inherently larger file size. Jpegs (.jpg) are fine for smaller prints but because of their image lossy nature it is not recommended that you save any files in this format. Images shot as in-camera Jpegs are once again mostly suited to small to medium prints. And naturally we are happy to accept RAW camera files. Once again, please do not hesitate to get in contact if you have any questions about file formats for photographic prints.

File Sizes

The following table should give you a good idea of the recommended digital file sizes for different sized photographic prints. As a rule of thumb – the larger the print size required, the larger the file size must be. There is however some leeway with the image resolution or dpi and how our Giclée or Lambda printers deal with this. For instance: if your image file is approximately 20MB at 400 dpi it will make an excellent print at A5 size. The same 20MB file will still make an excellent 10x8" print at 300 dpi, and a very good 16x12" print at 200 dpi. If you are in any doubt, go for a higher resolution for the print size required. Please contact us if you need any further assistance with file sizes for photographic prints.