Auto Adjust
Corrects contrast, a color cast, or white balance by itself, and works the correction out again whenever the image changes.
The Auto buttons on Levels and White Balance set values once. Auto Adjust runs the same methods live: change anything upstream and the correction follows, and every frame of a batch gets its own. For the same image, method, and bit depth it gives the same values the buttons would, so you can start live and bake the result into Levels or White Balance later.
It has three inputs: Image, the picture to correct; Reference, an optional image to work the correction out from; and the standard Mask.
Method, Clip, and Amount
Section titled “Method, Clip, and Amount”Method chooses what to correct:
- Contrast (the default) stretches the tone so the image runs from black to white, and never shifts color.
- Contrast and Color also removes a color cast, setting Red, Green, and Blue separately so the near-neutral midtones land on neutral gray.
- White Balance only removes a cast, by finding the surfaces most likely to be neutral gray, as White Balance’s Auto does.
- White Balance and Contrast does both, the white balance first.
Clip is how much of the darkest and lightest pixels to ignore at each end, from 0 to 5% (0.1% to start with), so one hot highlight cannot set the range. It is hidden while Method is White Balance, which has no range to set.
Amount scales the correction itself rather than mixing two pictures, so 50% is half the stretch or half the color shift. Changing Amount, or editing any node after Auto Adjust, never works the correction out again.
Reference: one correction for every frame
Section titled “Reference: one correction for every frame”With nothing on Reference, each image is corrected on its own, and so is each frame of a batch. That suits a folder of unrelated photos.
Across an animation or an image sequence that can flicker: a bright object moving into one frame changes that frame’s stretch, and the whole picture pumps brighter and darker. Wire one image into Reference to avoid it. The correction is worked out from the Reference and applied to every image on Image; a representative frame of the sequence works well. The Reference’s transparent pixels are left out of the analysis. Wire a batch into Reference instead and its frames pair with the main input’s frame by frame.
To give a whole batch one fixed correction, as for photos shot under the same light, you can also use Levels or White Balance, which apply one set of values to every frame.
Result
Section titled “Result”The Result section shows, read-only, what the node worked out for the frame the Preview shows: the Frame (“Frame 3 of 12”) on a batch, the Source (This image or Reference), and the values, in the units of the node you would bake them into:
- Temperature and Tint, as on White Balance, when the method includes white balance.
- Black and White, as Levels’ Master Input rows show them, for Contrast and for White Balance and Contrast.
- Red, Green, and Blue, each with its black point, white point, and gamma, for Contrast and Color.
To bake a result, set the same values on a Levels or White Balance node, or press that node’s Auto with the same method.
When a step is skipped
Section titled “When a step is skipped”Auto Adjust never stops the graph with an error. A step it cannot do is left out, and a line under the Result says why:
- No reliable neutral areas found: white balance changes nothing when it is unsure, because too few areas could be neutral, they disagree about the light, or the color looks like the scene rather than the light. That is common, and intended, on painted art, pixel art, flat-color illustration, and a deliberate sunset: their colors are the picture, not a cast.
- Contrast skipped: almost every pixel is the same brightness, so there is no range to stretch. A lower Clip counts more of the few pixels that differ.
- Color skipped: one color channel has almost no range, such as a picture with no blue in it, so only the contrast is corrected.
- One channel: a mask or grayscale input still gets Contrast; the color and white balance steps are left out.
- The Reference has no visible pixels: nothing changes.
Texture sets
Section titled “Texture sets”On a texture set or a library, a Map row at the top of the panel picks the color map to correct, Base Color to start with, and every other map passes through untouched. See Changing one map.
Parameters
Section titled “Parameters”Pins
Adjust
Which map of the texture set this node edits. Every other map passes through unchanged. Shown while a texture set or a library is wired
What to correct. Contrast stretches tone and never shifts color; Contrast and Color also removes a cast; White Balance only removes a cast; White Balance and Contrast does both, one after the other
How much of the darkest and lightest pixels to ignore, so a few stray pixels cannot set the range
How much of the correction to apply
Mask
How the connected color image is read as a mask
How the mask is sized when it doesn't match the image
Usage Tips
Section titled “Usage Tips”- Wire a representative frame into Reference for an animation, so the correction holds still across the sequence.
- Leave Reference empty for a folder of unrelated photos; each one gets the correction it needs.
- Use White Balance and Contrast on a photo with both a cast and a flat tone, and plain Contrast on art whose colors should stay as they are.
- Connect a mask to correct only part of the image.