Colors action (menu entry: Actions->Colors)
This action performs various color adjustment on active image using various color transformation modes.
| Brightness | Change the value of RGB channels by percentage set through RGB sliders. |
| Color stretch | Stretch RGB values by some percentage. |
| Hue Saturation Value | Change HSV values by some percentage. |
| Low Medium High | Change LMH value by some percentage: each pixel luminance value (covered by some ROI*) is checked against the class range (Low -> [0, 85], Medium->[86, 170], High->[171, 255]); RGB luminance is adjusted for each class separately using appropriate sliders. |
| Gamma | gamma correction |
| Exchange channels | RGB channels swapping using respective check boxes. Note that there are minimum two channels checked. |
| Max channels | Replace RGB channels by maximum value of checked channels. |
| Min channels | Replace RGB channels by minimum value of checked channels. |
| Exchange Min Max | Swap channels with minimum and maximum values. |
| Cast colors | Depending on slider position, pixel luminance is divided in three classes (similar to LMH), but the range values are not fixed (slider values). Pixel value is replaced by mapped color value for each range class. |
| Scale & range | Down-scales pixels range to new min-max values: from [0, 255]->[slider_min, slider_max] |
| Temperature | Adjusts pixels color according to color temperature value set by slider |
| Toning | Performs image toning either using single color or using current brush palette (see brush tool topic). |
| Color curves | Adjusts image color using color curves; a set of predefined color curves is available (of course, you can change them or create your own and save it) |
| Statistical correction | This mode requires at least two images loaded in IMA. Applying this mode to a single image is idempotent operation. It actually adjusts colors of source image according to color tones from target image. Before performing this operation, color data must be collected. |
Few important notes:
- ROI stands for Region of Interest: it can be region covered by a brush stroke or can be complete image/selection when action is applied using one of four cats..meow.
- In modes where percentage sliders are involved, you’ll see two radio buttons: Current pixel % and Max [255] %. When the first radio button is checked, adjustment will be applied locally, i.e. percentage refers to current pixel (channel) value. The second option will take maximum channel value (255) and calculate adjustment percentage.
- Statistical correction: color data are collected by selecting target image (source image is currently active tab). If some selection exists on source/target image and if respective check-boxes are checked, color data are calculated with respect to pixels under selection.
Following: Pixels shifting (probably tomorrow..one topic per day).