# Example: Creating a profile manually

The following screenshot illustrates a typical use of the manual profiling tool:

Several points are worth making:

- Each selection is uniform in tone and color. No edges or other detail are included in any of the selections. This is very important. Otherwise, the noise measurements will be significantly overestimated.
- Sometimes you need to be careful to judge uniformity. For instance, on the forearm, the tone changes subtly in the area just outside the selection. If the selection is made large enough to include the tone changes, then the tone change might be incorrectly interpreted by the profiler as low-frequency noise.
- The selections cover the major colors and tones in the image. In particular, there are selections in the shadows, midtones, and highlights. In this particular image, noise in dark areas is much stronger than noise in light areas, so it is important that this is reflected in the profile.
- Measuring the relative intensity of low-frequency noise requires a large selection (roughly 70x70 pixels or larger). Thus, it is good to have at least one large selection. (If not, then "reasonable" default values will be used for the low-frequency noise.)
- There is a modest number of selections. It isn't necessary to select every color and tone, or to select every part of the image. In some cases, two or three selections will provide enough information to characterize noise levels for the entire image.