Adobe Photoshop CS5 for Photographers - Martin Evening [292]
4.
I then zoomed in on the image to identify the darkest shadow point and clicked with the shadow point tool to set the new shadow value (having done this, you may want to use the Levels Gamma slider to adjust the relative image brightness).
CMYK to CMYK
It is not ideal for CMYK files to be converted to RGB and then converted back to CMYK, as this is a sure-fire way to lose data fast. I always prefer to keep an RGB master of each image and convert to CMYK using a custom conversion to suit each individual print output. Converting from one CMYK space to another is not really recommended either, but in the absence of an RGB master, this will be the only option you have available: just specify the CMYK profile you wish to convert to in the Convert to Profile dialog box. Remember, the Preserve Embedded Profiles policy ensures that tagged incoming CMYK files can always be opened without converting them to your default CMYK space (because that would be a bad thing to do). This means that the color numbers in the incoming CMYK files are always preserved, while providing you with an accurate display of the colors on the computer display.
Lab color
The Lab color mode is available as a color mode to convert to via the Image Mode menu and the Convert to Profile command, but note that the Lab color space does not use embedded profiles since it is assumed to be a universally understood color space. It is argued by some that converting to Lab mode is one way to surmount all the problems of mismatched RGB color spaces. You could make this work, so long as you didn't actually do anything to edit the image while it was in Lab mode, but I wouldn't really advise this. In fact, these days I see less and less reason to use the Lab color mode in Photoshop. Now, a few people have taken me to task over not covering Lab mode image editing in this book, so let me clarify why I don't see editing in Lab mode as being so useful now for high-end image editing. In the early days of Photoshop I would sometimes use the Lab color mode to carry out certain tasks, such as sharpening the Lightness channel separately. This was before the introduction of layers and blending modes, where I soon learnt that you could use the Luminosity and Color blend modes to neatly target the luminosity or the color values in an image without having to convert to Lab mode and back to RGB again. While it is true that Luminosity blend mode sharpening is not exactly the same as sharpening the Lightness channel, such arguments have been further superseded by the latest improvements to Camera Raw sharpening, where it is now possible to filter the luminance sharpening using the Detail and Masking sliders (see Chapter 4).
Let's just say that there are no right or wrong answers here. If you can produce good-looking prints using whatever methods work best for you, and you are happy with the results, well who can argue with that? However, I would hope by now that having learnt about optimizing tones and colors in Camera Raw, followed by what can be achieved using Photoshop, you'll realize that these are all the tools you'll ever need to process a photograph all the way through to the finished print stage. My response to the Lab color argument is that it is simply adding complexity where none is needed. There are good reasons why in recent years the Adobe engineering teams have devoted considerable effort to enhancing the Camera Raw image editing for Photoshop and Lightroom. Their aim has been to make photographic image editing more versatile, less destructive and above all, simpler to work with.
Info panel
Given the deficiencies of typical computer color displays, such as their limited dynamic range and inability to reproduce certain colors like pure yellow, color professionals may sometimes rely on the numeric information to assess an image. Certainly, when it comes to getting the correct output of neutral tones, it is possible to predict with greater accuracy the neutrality