If you are working with photos from a variety of sources you will find that they have very different characteristics: Some may appear warm, others much cooler. Daylight produces different color casts depending upon the time of day the shot was taken, and indoor photos will often be lit by a combination of artificial and natural light. Artificial lighting may be fluorescent (cool) or incandescent (warm). All of these present potential problems to the designer, because they add image-wide color casts which are not wanted.

It is tempting to ask the printer to take care of all this for you, but that is a very costly way to fix something that you could quite easily do yourself. With experience, you will never have to ask someone else to step in and do the work for you—because you can do it better. And, you have the best incentive: Nobody else will ever be as concerned about the quality of your work as you are.

As long as you save your work under a new name you do not need to worry about damaging the source material. Add to that the “history” (the multiple undo capability in Adobe Photoshop), and you can see the process is foolproof: You can always go back to the beginning if you think your adjustments are not good enough. So, jump right in with confidence. Who knows—this may become the part of your design work that you enjoy the most.