Adobe Photoshop CS5 for Photographers - Martin Evening [268]
So why can there sometimes be such a marked difference between what is seen on the display and the actual printed result? Well, digital images are nothing more than just bunches of numbers, and good color management is all about making sense of those numbers and translating them into meaningful colors at the various stages of the image making process.
The way things were
Sixteen or more years ago, most photographers only used their computers to do basic administration work and there were absolutely no digital imaging devices to be found in a photographer's studio (unless you counted the photocopier). If you needed a color print made from a chrome transparency, you gave the original to the printer at a photographic lab and they matched the print visually to your original. Professional photographers would also supply chrome transparencies or prints to the client, and the photographs then went to the printer to be digitized using a high-end drum scanner, which would be configured to produce a CMYK file ready to insert in a specific publication. That was probably about the limit of the photographer's responsibilities, and if color corrections were required, the scanner operators would carry this out themselves working directly on the output file.
These days a significant number of photographers, illustrators and artists are now originating their own files from digital cameras, desktop scanners or directly within Photoshop. This has effectively removed the repro expert who previously did all the scanning and matching of the colors on the press. Therefore, there is no getting away from the fact that if you supply digital images to a printer, you will be deemed responsible should any problems occur in the printing. This may seem like a daunting task, but with Photoshop it really isn't that hard to color manage your images with confidence.
Color management references
If your main area of business revolves around the preparation of CMYK separations for print, then I do recommend you invest in a training course or book that deals with CMYK repro issues. I highly recommend the following books: Real World Color Management by Bruce Fraser, Chris Murphy and Fred Bunting; Color Management for Photographers by Andrew Rodney; and Getting Colour Right, The Complete Guide to Digital Colour Correction by Neil Barstow and Michael Walker.
RGB devices
Successful color management relies on the use of profiles to describe the characteristics of each device, such as a scanner or a printer, and using a color management system to translate the profile data between each device in the chain. Consider for a moment the scale of such a task. We wish to capture a full color original subject, digitize it with a scanner or digital camera, examine the resulting image via a computer display and finally reproduce it in print. It is possible with today's technology to simulate the expected print output of a digitized image on a computer display with remarkable accuracy. Nevertheless, one should not underestimate the huge difference between the mechanics of all the various bits of equipment used in the above production process. Most digital devices are RGB devices and just like musical instruments, they all possess unique color tonal properties, such that no two devices are always identical or able to reproduce color exactly the same way as another device. Nor is it always possible to match in print all the colors which are visible to the human eye, and converting light into electrical signals via a device such as a CCD chip is not the same as illuminating the pixels on an LCD display or reproducing a photograph with colored ink on paper.
Why not