If you've used RawTherapee for a while you may notice that you almost always need a positive Exposure Compensation - as if all your photos are underexposed. Enabling " Highlight Reconstruction" will prevent this flat-gray look to some degree by recovering highlight information from the remaining non-clipped channels. If you try decreasing the exposure of a photo which contains clipping, you will notice that the clipped areas turn flat-gray. This means this slider changes the black point (on the very left of the histogram) and the white point (on the very right). Moving it to the right shifts the whole histogram to the right. Take a look at the histogram while moving this slider. If you make two photos, one without correction (EV = 0) and one underexposed by one stop (EV = -1), you can make both photos match by setting exposure compensation for the overexposed photo to -1, or for the underexposed photo to +1. This means a value of +1 equals one stop of overexposure (+1 EV, exposure value also known as +1 LV, light value)). The values of the Exposure Compensation slider (EC) are ISO values. " Highlight Compression" values under 100 are recommended in most cases. " Highlight Compression" values under 100 are recommended in most cases.Īttempts to guess clipped color channels by filling in their values from the closest match from unclipped highlight regions nearby. Reduces the luminance channel and tries to restore colors afterwards. Works well even with very high " Highlight Compression" values (under 500). It is also computationally intensive and is therefore slower than the other methods. Its weakness is that it may sometimes 'bleed' the incorrect colors, depending on the image elements surrounding the blown highlights, or the colors can bleed into undesirable patterns. This method works best on small overexposed areas, and can work wonders on overexposed skin. In addition to restoring luminosity, Color Propagation tries to restore color information by 'bleeding' the surrounding known color into the missing clipped area. This is the most powerful recovery method. The Auto Levels button will automatically enable Highlight Reconstruction if necessary.įour different methods of highlight reconstruction are available: Remember, this tool is used for the reconstruction of clipped highlights, while if you just want to compress highlights which were not clipped in the first place but became clipped due to the use of, for example, Exposure Compensation, then use the Highlight Compression slider. Using the Color Propagation method, it can also guess clipped data using nearby data from unclipped channels, if present. ![]() It attempts to restore clipped (blown-out) regions in the raw image relying on the fact that the three channels in a raw file do not clip at the same time and so a missing (clipped) region in one channel could be guessed from the present data of one of the other color channels. Use Highlight Reconstruction (HR) to try to restore overexposed highlights in raw files. Higher values increase the contrast, lower decrease it.Īs of RawTherapee 5.5, while the Auto Levels tool in the Editor still uses the Clip % value, the thumbnails use a fixed value of 0.2% - this was done to reduce the number of files needed to be stored in the cache. The minimum value is 0.00, the maximum is 0.99. This number defines the percentage of pixels allowed to clip to the white and black points of the raw histogram. ![]() The Tone Curves will not be touched.Īuto Levels uses the "Clip %" value to adjust the exposure. You can reset all of the sliders in the Exposure section by clicking on the Reset button. not typical), in which case you should adjust the values yourself. For example you might be going for a high-key look (i.e. It has been tuned to work best with "typical shots", so the result should often be aesthetically pleasing, but as the program doesn't know your taste or expectations this will not always be the case. Think of the adjustments Auto Levels comes up with as a good starting point. It uses only the "Exposure compensation", "Highlight compression", "Highlight reconstruction", "Black", "Lightness" and "Contrast" sliders. The Auto Levels tool analyzes the histogram and then adjusts the controls in the Exposure section to achieve a well-exposed image.
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