|
Hello Deborah, I have not read the book you cite, but color in the RGB spectrum does not change..they are specific numerical values. I do not use the system you describe, but I can see why it is recommended in your book. They are nothing more than starting points to get you on the right track. For instance, the RGB values of 20,20,20 will be very dark, yet allow "some" shadow detail to remain visible. The midtone numbers you quote are a mystery to me. If you mean neutral gray, these numbers should be 1/2 the value of 255 for all three RGB levels. 244,244,244 are extreme white; 255 is the top value for white, so I'm not really sure why the author chose 244? I've seen this theory before, but as I said, I do not use it for several reasons. 1) It is a cookie cutter approach to "leveling" your images. Not all images require a flat value.
Perhaps some of your images have deep black shadows for instance. By setting the "black point" at 20, you are unnaturally lightening the shadows that have no detail anyway. 0,0,0 is black; period! Not (20). More to the point: I generally use the levels slider while holding down the "alt" key until I begin to see highlites on one end and shadows on the black point slider. Some people adjust this to taste, others use numerical values entered in the 3 boxes in levels.
The two end boxes are black point & white point..these are easy to set and not all that subjective. Now the center slider is indeed midtone. Midtone is a matter of taste AND is dependent on the image itself, be it a high or low contrast photo. If you really want to aggravate yourself (LOL) use "curves." I actually love curves in many situations. Curves have the ability to fine tune ANY of the 255 levels of brighness and magnitude of the RGB spectrum without affecting the other valuse. They can change only a small part of the image (i.e 20-40 range) as an example, and not touch the other values. Further, "curves" can be selectivly applied to parts of the image YOU decide need correction.
Levels is like a large brush, Curves are like a very fine brush. With all that said, you will find it is easy for all this to get out of control.
When you consider most printer/paper combinations can not re-produce many of the subtle changes anyway, a lot of this work has diminishing returns. Doing it by the numbers has some merit, but I feel it stifles creativity. Hope that helps a little and hasn't confused you further. ;) Pete
January 02, 2007
|
