Learn Phoduit

9.3 Color

9.3.1 Color Profile

The Color Profile node converts an image from one color space to another using ICC color profiles.

See the Color Management section in Chapter 3. User Interface for details on managing color profiles.

Input

Image
Image to have its color space changed.
Input Color Profile
The color profile for the color space to be changed from. Set to “Automatic” to use the input image’s current color profile.
Output Color Profile
The color profile for the color space to be changed to.
Rendering Intent
How colors should be transformed when they cannot be accurately reproduced in the output color space. The actual result of this setting often differs depending on the selected color profiles.
Rendering Intent Usage Description

Perceptual

Recommended for photographs

Hue is saved at the cost of saturation and lightness.

Relative Colorimetric

Saturation and lightness are saved at the cost of hue.

Saturation

Recommended for business graphics

Hue and saturation are maintained at the cost of lightness.

Absolute Colorimetric

Hue and lightness are maintained at the cost of saturation.

Mode

Operation to be performed.

  • Transform: Transform from one color space to another and assign the output color profile to the output image.
  • Cast: Assign the output color profile to the output image but do not actually operate on the image’s pixels.

Output

Image
The input image converted to the color space defined by the output color profile.

9.3.2 Contrast

The Contrast node performs traditional contrast and brightness adjustments on an image. This node is named “Contrast” for historical purposes in reference to very specific functionality. While still useful for working with masks, you should consider using the Levels node for other images.

Input

Image
The image to have its contrast and brightness adjusted.
Contrast
How much to brighten bright parts and darken dark parts of the input image.
Brightness
How much to brighten or darken all parts of the input image.

Output

Image
The input image with its contrast and brightness adjusted.

9.3.3 Curves

The Curves node smoothly remaps the tones of an image.

See Tone correction and Color correction in Chapter 4. Essentials for examples.

Input

Image
The image to have its tones remapped.
Preset

Available curve presets. Selecting a curve preset changes the RGB, Red, Green, and Blue curves.

  • Default: Sets all curves to linear which produces an output image that is identical to the input image.
  • Embedded: Set all curves to those embedded in the input image. Only available with certain raw images imported with the Raw Image Open node.
  • Custom: Allows curves to be freely adjusted.
Channel
The channel currently being edited. While only one channel can be edited at a time, all channels are applied.
Curves
The curves used to remap the tones of the input image. The input tones are horizontal and the output tones are vertical. Left click and drag within the curve editor to place a knot. A knot can be left clicked and dragged to be repositioned. Knots can be deleted by left clicking and dragging them left or right until they disappear or by left clicking to select and pressing the Delete key. To reset the current channel’s curve to linear, left click the “Reset Channel” button at the bottom of the node.

Output

Image
The input image with its tones remapped.

9.3.4 Exposure

The Exposure node brightens or darkens an entire image.

Input

Image
The image to have its exposure adjusted.
Exposure
The amount to brighten or darken the input image. Use negative values to darken and positive values to brighten.

Output

Image
The input image with its exposure adjusted.

9.3.5 Greyscale

The Greyscale node converts an image to greyscale so that the red, green, and blue channels are all identical.

Input

Image
The image to be converted to greyscale.
Type

How colors should be converted to greyscale.

  • Luma (Y’UV): Y’ channel of the Y’UV color space as defined by the NTSC standard.
  • Luma (HDTV): Y’ channel of the Y’UV HDTV color space as defined by Rec. 709.
  • Lightness: L channel of the HSL color model.
  • Average: Adds each channel together and uses the average.
  • Value: V channel of the HSV color model.
  • Red: Red channel of the input image.
  • Green: Green channel of the input image.
  • Blue: Blue channel of the input image.
  • Alpha: Alpha channel of the input image.

Output

Image
The input image converted to greyscale.

9.3.6 HSL Channels

The HSL Channels node adjusts the hue, saturation, and lightness of an image using the HSL color model.

See Color correction in Chapter 4. Essentials for an example.

Input

Image
The image to have its hue, saturation, and lightness adjusted.
Hue
Rotate the spectrum. The range should be treated as a continuous 360 degree ring where a value of -180 is the same as a value of 180.
Saturation
Adjust the “colorfulness” of colors.
Lightness
Adjust the brightness of colors relative to white.

Output

Image
The input image with its hue, saturation, and lightness adjusted.

9.3.7 Invert

The Invert node negates the values in the red, green, and blue channels of an image.

Input

Image
The image to be inverted.

Output

Image
The input image as inverted.

9.3.8 Levels

The Levels node remaps the tones of an image. It’s often used for adjusting the contrast of a photograph.

Adjustments made with the Levels node can also be done with the Curves node but not necessarily the other way around. The Levels node is easier to use so you should try using it first.

See Tone correction and Color correction in Chapter 4. Essentials for examples.

Input

Image
The image to have its tones remapped.
Channel
The channel currently being edited. While only one channel can be edited at a time, all channels are applied.
Input
The range of tones to be remapped. Tones outside of this range are clipped. Use the histogram above this field to gauge where the tones are to minimize clipping.
Gamma
Brighten or darken the tones before they are mapped for output. Values less than 1.0 darken, a value of 1.0 leaves the tones unchanged, and values greater than 1.0 brighten.
Output
The range that tones will be remapped to. No tones will be produced outside of this range. Anything other than a range of 0 and 65535 tends to make the output image hazy.

Output

Image
The input image with its tones remapped.

9.3.9 RGB Channels

The RGB Channels node brightens or darkens the red, green, and blue channels individually.

Input

Image
The image to be adjusted.
Red
Amount to brighten or darken the red channel. Negative values darken and positive values brighten.
Green
Amount to brighten or darken the green channel. Negative values darken and positive values brighten.
Blue
Amount to brighten or darken the blue channel. Negative values darken and positive values brighten.

Output

Image
The input image with its RGB channels adjusted.

9.3.10 Soft Proof

The Soft Proof node simulates how an image would look when printed. Keep in mind that additive color mixing, as used by a typical computer’s LCD display, cannot accurately reproduce how colors are perceived when viewed on a subtractive color mixing medium, such as ink on a piece of paper. While not perfect, soft proofing can produce images that look very close to print which can save you a lot of money on print costs.

You must calibrate your display using a hardware display calibrator and set Phoduit to use the resulting color profile. Calibrating your display manually by eye is NOT accurate enough for soft proofing.

You must also have installed a color profile calibrated for the inks, paper, and lighting conditions that you want to view your printed photograph under. If Phoduit does not automatically find your installed color profile, you can import it in the Color Management section of the Preferences dialog.

Because the output image produced by this node is the simulated output of a printer, you should do all of your processing, including sharpening for print, first.

Input

Image
The image to be soft proofed.
Color Profile
The calibrated CMYK color profile for the ink, paper, and lighting conditions you intend to view your prints under.
Rendering Intent
How colors should be transformed to the CMYK color space. The actual result of this setting often differs by color profile. You will usually want to set this to “Saturation” for soft proofing.
Rendering Intent Usage Description

Perceptual

Hue is saved at the cost of saturation and lightness.

Relative Colorimetric

Saturation and lightness are saved at the cost of hue.

Saturation

Recommended for soft proofing

Hue and saturation are maintained at the cost of lightness.

Absolute Colorimetric

Hue and lightness are maintained at the cost of saturation.

Out of Gammut

Indicate which pixels have colors that cannot be accurately reproduced using the selected Color Profile. Out of gammut pixels are indicated using a maximum red color.

  • Hide: Do not show which pixels are out of gammut. Just transform them as defined by the Rendering Intent.
  • Show: Show which pixels are out of gammut.
Black Point Compensation
Remap grey balance to print medium. This does not work with most color profiles unless the Rendering Intent is set to “Relative Colorimetric”.

Output

Image
The input image as soft proofed.

9.3.11 White Balance

The White Balance node changes the color cast of an image. It’s usually used to make tones that should be neutral actually neutral.

Input

Image
The image to have its color adjusted.
Preset

Available temperature and tint presets. Selecting a preset changes the Temperature and Tint fields below.

  • Camera: If the input image was imported with a Raw Image Open node and white balance information is available, it will be used. Otherwise, CIE Standard Illuminant D65 (daylight) is used.
  • Custom: Temperature and Tint are freely adjustable.
Temperature
The temperature of the lighting the image was created under in kelvin. Smaller values indicate the image was created under “warmer” looking lighting and larger values indicate the image was created under “cooler” looking lighting.
Tint
The amount to shift colors away from the selected temperature. Values smaller than 1000 make the image more pink and values larger than 1000 make the image more green. Set to 1000 to not shift the colors.

Output

Image
The input image with its colors adjusted.

Mode

There is one tool available to interact with the White Balance node.

Icon Name Keyboard Shortcut Description

White Balance

W

Left click or left click and drag your cursor over the region in the Canvas that you would like to become neutral. Try to select an area that is not fully white or fully black for best results.