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description: "Photoshop Color Correction & Grading — Level 1's Curves/Hue-Saturation adjustment layers (Module 6) covered quick, everyday fixes. This module goes deeper…"---

02 · Photoshop Color Correction & Grading

Level 1's Curves/Hue-Saturation adjustment layers (Module 6) covered quick, everyday fixes. This module goes deeper into deliberate color work: reading and shaping a Curves adjustment precisely, correcting cast with Color Balance, and grading a shot wholesale with the Camera Raw Filter — the same engine Lightroom uses, available directly inside Photoshop.

1. Curves, precisely

Curves (Level 1 introduced it as one option among several) is worth understanding in real depth — it's the single most flexible tonal tool in Photoshop.

  1. Add a Curves adjustment layer (Layer > New Adjustment Layer > Curves, or the half-filled circle icon in the Layers panel). The graph shows input (x-axis, original tones) against output (y-axis, adjusted tones), running from black (bottom-left) to white (top-right).
  2. Click anywhere on the diagonal line to add a control point, then drag it up (brightens that tonal range) or down (darkens it).
  3. An S-curve — one point pulled slightly down in the shadows, another pulled slightly up in the highlights — is the classic contrast boost: deepens blacks and brightens whites while leaving midtones roughly alone.
  4. Use the on-image adjustment tool (the hand icon with arrows at the Curves panel's top-left) to click directly on the photo and drag up/down — Photoshop places a matching point on the curve at that exact tonal value automatically, useful when you know which part of the photo needs adjusting but not its numeric value.
  5. Switch the channel dropdown (top of the panel, default RGB) to Red, Green, or Blue individually to correct a color cast — e.g. pulling the Blue channel's curve down in the shadows removes a blue tint from dark areas without touching brightness overall.
  6. Reset any curve to its default diagonal by holding Option/Alt and clicking Reset in the Properties panel, or by deleting individual points (select a point, press Delete).

2. Color Balance

Color Balance targets color cast per tonal range in a simpler, slider-based way than Curves' per-channel curves — a faster tool once you know roughly what's wrong.

  1. Add a Color Balance adjustment layer (Layer > New Adjustment Layer > Color Balance).
  2. Choose a Tone range at the top of the Properties panel — Shadows, Midtones, or Highlights — and drag the three sliders (Cyan–Red, Magenta–Green, Yellow–Blue) toward whichever color is missing.
  3. A common real-world fix: a photo shot under indoor tungsten lighting looks too orange/yellow overall — select Midtones, drag the Yellow–Blue slider toward Blue, and the Cyan–Red slider slightly toward Cyan, to neutralize it.
  4. Check Preserve Luminosity (checkbox at the bottom) to keep overall brightness unchanged while only shifting color — usually worth leaving on so a color fix doesn't also brighten or darken the image as a side effect.
  5. Correct shadows, midtones, and highlights as three separate light passes rather than trying to fix everything with one slider drag — most real color casts aren't uniform across the whole tonal range.

3. Camera Raw Filter

The Camera Raw Filter brings Lightroom's full adjustment engine into Photoshop as a filter, applying its own complete panel of controls in one place rather than stacking several separate adjustment layers.

  1. Select a layer (convert it to a Smart Object first, Module 1, so the filter stays editable as a Smart Filter afterward) and choose Filter > Camera Raw Filter (Shift+⌘/Ctrl+A).
  2. The Basic panel covers the most common moves top to bottom: Exposure (overall brightness), Contrast, Highlights/ Shadows (recover detail at each end independently), Whites/ Blacks (set the actual clipping points), Texture, Clarity (midtone contrast/punch), Dehaze (cuts through atmospheric haze), and Vibrance/Saturation (Vibrance boosts muted colors more than already-saturated ones, giving a more natural result than Saturation's flat boost).
  3. The Curve tab gives the same point-curve control as Photoshop's own Curves, inside the same dialog.
  4. The Color Mixer tab (HSL-style) adjusts Hue, Saturation, and Luminance per individual color range (e.g. push just the oranges more saturated for skin tones without affecting blues in the sky).
  5. Color Grading applies the "wheels" look familiar from video grading — separate color wheels for Shadows, Midtones, and Highlights, each with its own Hue and Saturation control, good for a cohesive stylized look across a whole batch of photos.
  6. Click OK to apply. On a Smart Object, the result appears as an editable Camera Raw Filter Smart Filter beneath the layer — double- click its name any time to reopen and adjust every setting again.

Camera Raw Filter vs. adjustment layers

Camera Raw Filter bakes its settings into one Smart Filter entry rather than separate adjustment layers, which makes it faster to apply a consistent full grade to many photos, but harder to mask different settings to different areas independently. For that kind of localized control, separate adjustment layers with masks (Level 1, Module 6) are still the better tool — the two approaches are complementary, not competing.

4. A full grading workflow, end to end

  1. Convert the photo layer to a Smart Object first (Module 1) so every step below stays editable.
  2. Apply Camera Raw Filter for the broad first pass — Exposure, Contrast, Highlights/Shadows recovery, and a Color Grading wheel tweak for overall mood.
  3. Add a Curves adjustment layer above it for a final contrast S-curve and any per-channel cast correction the Camera Raw pass didn't fully fix.
  4. Add a Color Balance adjustment layer if a specific tonal range (often shadows) still reads slightly off after Curves.
  5. Mask any adjustment layer (Level 1, Module 6) that shouldn't apply everywhere — e.g. excluding a subject's face from a shadows-heavy mood grade meant for the background.

Cheat sheet

Tool Best for
Curves Precise per-channel tonal and color cast control
Color Balance Fast, slider-based cast correction per tonal range
Camera Raw Filter Full one-pass grade: exposure, color wheels, HSL mixer
Vibrance (in Camera Raw) Natural saturation boost, protects skin tones
Saturation (in Camera Raw) Flat, uniform saturation boost — easy to overdo
Action Shortcut
Open Camera Raw Filter Shift+⌘/Ctrl+A
New Curves adjustment layer Layer > New Adjustment Layer > Curves
New Color Balance adjustment layer Layer > New Adjustment Layer > Color Balance
On-image Curves adjustment tool Curves Properties panel, top-left hand icon
Convert layer to Smart Object first Layer > Smart Objects > Convert to Smart Object

How It Actually Works

  • A curve is a remapping function applied per input tone value, not a freehand paint stroke. Every point you place defines a coordinate on an input→output mapping; Photoshop interpolates a smooth spline through all placed points and applies the resulting function to every pixel whose original value falls along that curve — a pixel at input value 128 simply looks up what output value the curve currently assigns to 128. That's why an S-curve boosts contrast without an explicit "increase contrast" operation: pulling shadows down and highlights up is literally remapping dark input values to darker outputs and light input values to lighter outputs, while midtones near the curve's unmoved center stay close to their original value.
  • Per-channel curves work because a color image is three independent numeric planes. Selecting the Blue channel and pulling its shadow region down doesn't touch Red or Green at all — it remaps only the blue component of every pixel below a certain blue value. A blue-tinted shadow has an elevated blue value relative to red/green at that brightness; lowering just blue's curve there brings the three channels back into closer balance without an explicit "remove blue cast" operation — you're just applying arithmetic to one plane of the data.
  • Vibrance and Saturation use different weighting formulas on the same underlying data, which is the entire reason they look different. Saturation applies a uniform multiplier to every pixel's saturation value regardless of how saturated it already is. Vibrance's algorithm weights that multiplier inversely to existing saturation — it boosts low-saturation pixels much more than already-saturated ones, and further applies extra damping specifically in skin-tone hue ranges. This is a deliberate, hardcoded protection in Adobe's Vibrance implementation, not an emergent side effect — it's why Vibrance is the safer default for photos with faces.
  • Camera Raw Filter and separate adjustment layers apply changes at different points in the same rendering pipeline. Camera Raw operates on the Smart Object's source data through a single unified processing pipeline (demosaic-equivalent tone/color math, done once, in one pass) before Photoshop's normal layer-compositing engine ever runs, which is why it's efficient for a full-image grade but only exposes one mask for the whole filter. Adjustment layers instead operate at the Photoshop compositing stage itself, each with its own independent mask evaluated per-pixel during the same top-down compositing walk covered in earlier modules — that's the structural reason stacking several masked adjustment layers gives you localized control that one Camera Raw pass structurally cannot.
  • "Preserve Luminosity" in Color Balance works by converting to a luminance-preserving color model before and after the shift. Internally, Photoshop measures the pixel's luminance value before applying the Cyan-Red/Magenta-Green/Yellow-Blue shifts, then rescales the resulting RGB values after the shift so the same luminance value is reproduced — this is a real corrective calculation each time, not a checkbox that merely limits how far you can drag the sliders.

Exercise

Open a photo with a visible color cast (indoor tungsten lighting or an overcast/blue-toned shot both work well). Convert its layer to a Smart Object, apply the Camera Raw Filter for a broad exposure and color-wheel correction, then add a Curves adjustment layer on top for a final S-curve contrast boost. If any cast remains in just the shadows or midtones, add a Color Balance adjustment layer targeted at that tonal range. Mask at least one adjustment so it doesn't apply to the whole image.