Vintage “Colombian” printing press in Swindon College Print Department.
1. Use sRGB colour space
Colour space determines the gamut (range) of colours available. sRGB is the de-facto standard developed by HP and Microsoft in the 1990’s for monitors, printers and the internet.
The intention is that an image displayed on any sRGB compliant device will appear the same. In reality many factors can affect this, is the device properly calibrated – i.e. adjusted to the specified standard. If print format the quality of ink and paper will affect the appearance. Regardless sRGB is the colour profile which will produce the most reliable results in print or on the web.
In Photoshop, you can convert the profile of your images using Edit > Convert to Profile. Or, for batch conversion, you can use the trusty File > Scripts > Image Processor.
2. File format
DSLR camera will save files typically either as camera raw file or jpgs, more advanced cameras will save both types simultaneously. Raw formats are unique to each camera / manufacturer, jpg is a the most common format encountered.The advantage of raw files is the amount of information they contain, enabling much more control in post processing. The disadvantage is size as typically they are very large files, size affects storage, backup and computing power required to process and or manipulate.
The sample image above is 25MB RAW file as captured, 3.8MB when converted to a full size (5796 x 3870 pixels) .jpg file or a mere 0.1Mb when reduced to a 1030 x 690 .jpg for web use. There is no point using large files for the web as typically most monitors don’t display much above 1030 pixels and by using larger files you are severely impacting the perceived speed of your website – in the example above it would take 40 times as long to download the image from a website.
Depending on their needs some professionals will shoot in RAW e.g. Landscape and Portrait Photographers as they value the control RAW provides. Alternatively News and Sports photographers may opt to shoot in .jpg due to the file size and thus accompanying speed if they have to upload files from remote locations.
Whilst raw files are undoubtedly the most detail rich, Jpg is really the only choice for sharing photos. All applications can view them, and they’re conveniently small. No other format is as generic or supported. There tends to be a small amount of confusion surrounding Jpg files quality. It is widely stated that jpg is a lossy format – i.e. the image quality degrades. This is correct over many openings and editing of a file however using a high quality jpg as the final version of an image for printing will be fine.
3. Process and Edit Image.
If using RAW files then they will need to be processed, if using ADOBE products then typically with Adobe Camera Raw (ACR), ACR provides control for exposure, white balance and hue, vibrancy and saturation along with some basic editing tools such as crop, straighten and red eye removal and more advanced colour management tools. If an image is well captured in camera processing with ACR may well be all that is necessary unless specific effects are required from within Photoshop.
4. Sharpen Image
The last step should be sharpening.
Sharpening is a minefield all of its own and the output will depend on the paper type, size of image and quality of printing as the simple truth is, there’s no “one size fits all” sharpening setting. An aggressive amount of sharpening may look great if the file is reduced in size for a small print (eg 6×4 or 5×7), but look less than optimal if the file is enlarged for a wall print. On the other hand, a light sharpen will look fine for a big print, but disappear on a small print, as if you hadn’t sharpened at all. Neither option is perfect, but the latter is generally much more acceptable.
5. Brighten Image
Typically you need to adjust the brightness of the image for printing, monitors tend to be too bright for printing. Start by reducing the brightness of your monitor to around 30%, then brighten your image appropriately. It does seem strange at first, but if you don’t do this, photos will often come out too dark.
When all adjustments have been made save a .jpg with a resolution of 300 dpi in order to ensure good quality print – although ideally this should be matched to the printer, if the printer resolution is higher than the image it will interpolate the “missing” information and the image may look pixellated, if the printer resolution is lower then it will discard the excess information again with a loss of control of the final image.
6. Printing Image.
All quality paper and printers come with an ICC colour profile, generally available from the paper or printer manufacturer. This is a piece of software that will ensure the best match between the printing process e.g Photoshop and the paper being used. So should be downloaded and installed for your printer set-up.
ICC is the International Colour Consortium a standards organisation with the “The purpose of the ICC is to promote the use and adoption of open, vendor-neutral, cross-platform colour management systems.
The ICC encourages vendors to support the ICC profile format and the work flows required to use ICC profiles” http://www.color.org/
The eight founding members of the ICC were Adobe, Agfa, Apple, Kodak, Microsoft, Silicon Graphics, Sun Microsystems, and Taligent but as as of 2014 there are over 60 organisations who are members including major camera, printer and display device manufactures.
If using a commercial photo lab they will typically provide a profile and and specification for how images should be submitted to get the best output.
Printed samples of output will be provided as hard copy.
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