Layer Blend Modes
Blend modes control how a layer's pixels mathematically interact with the layer below. Six modes cover 90% of professional use. Learn them once, apply them everywhere — from colour grading to shadow creation to photo compositing.
Every pixel on screen is described by three values — Red, Green, and Blue — each ranging from 0 (black) to 255 (full colour), or 0.0 to 1.0 in GIMP's internal floating-point representation. When two layers overlap, GIMP must decide what colour to display. The default mode — Normal — simply shows the top layer's pixel if it is fully opaque. Blend modes replace this with a mathematical formula.
In every blend mode formula, GIMP uses two values: the Blend colour (the active layer's pixel, also called the "source") and the Base colour (the pixel from the layer immediately below). The formula runs on each of the three channels (R, G, B) independently, then recombines them.
You don't need to memorise the maths. You need to know the effect each mode produces and the conditions under which that effect occurs. GIMP 3.2 lists 38 blend modes — but six of them appear in almost every professional workflow.
Skill unlock: After this session you can use blend modes to darken or lighten an image non-destructively, add contrast, tint colour, create shadow layers, and blend textures — all without permanently altering any pixel data.
The blend mode dropdown is in the Layers panel, directly above the Opacity slider. It defaults to "Normal". Work through each of the six modes below using a duplicated layer of any photograph.
| Mode | Effect | Neutral value | Primary use |
|---|---|---|---|
| Multiply | Always darkens. The blend and base values are multiplied together (as fractions of 1). Two mid-grey layers produce a darker mid-grey. | White = transparent | Shadows, darkening exposures, drop shadow layers, burning in texture |
| Screen | Always lightens. The inverse of Multiply: inverts both values, multiplies, then inverts the result. Two mid-grey layers produce a lighter mid-grey. | Black = transparent | Highlights, dodging, adding glow, combining fire/smoke elements |
| Overlay | Combines Multiply and Screen based on the base colour's luminosity. Dark base areas get darker (Multiply); light base areas get lighter (Screen). Mid-tones (50% grey) are neutral. | 50% grey = transparent | Contrast enhancement, applying textures, colour grading |
| Soft Light | A gentler version of Overlay — the transition between darkening and lightening is smoother. Produces a more subtle, photographic result. | 50% grey = transparent | Subtle contrast, lighting effects, skin retouching, dodge-and-burn techniques |
| Darken | Compares blend and base pixel values channel by channel, displaying whichever is darker. Does not blend — simply selects. | White = transparent | Removing white backgrounds, compositing dark elements (ink scans, line art) |
| Lighten | Compares blend and base pixel values channel by channel, displaying whichever is lighter. The opposite of Darken. | Black = transparent | Removing black backgrounds, compositing light elements (stars, glows, white logo on dark) |
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01
Set Up Your Test File
Open a photograph with a good range of tones (not too dark, not too overexposed). Duplicate the base layer three times so you have four identical layers. Name them: "base", "test Multiply", "test Screen", "test Overlay". Turn off visibility on the top three — you'll work on one at a time.
Layer → Duplicate Layer (×3) — rename each in the Layers panel -
02
Apply Multiply — Controlled Darkening
Turn on visibility for "test Multiply". Select it. In the Layers panel, click the mode dropdown (currently "Normal") and choose "Multiply". The image darkens dramatically — two identical images multiplied together produce an extreme result. Reduce the layer's opacity to 40–60% to achieve a realistic shadow-darkening effect. This is how you add weight to an image that looks washed out.
Layers panel → Mode dropdown → Multiply. Then adjust Opacity. -
03
Apply Screen — Controlled Lightening
Turn on "test Screen". Set its mode to Screen. The image brightens and shadow detail opens up. This is equivalent to a gentle "lift" of the entire image — useful for recovering underexposed photos. Reduce opacity to 30–50% and observe how it affects the shadow regions most. Notice the highlights begin to blow out at high opacity — Screen cannot create detail that isn't there; it can only lift what exists.
Layers panel → Mode dropdown → Screen. Then adjust Opacity. -
04
Apply Overlay — Contrast and Punch
Turn on "test Overlay". Set its mode to Overlay at 100% opacity. You'll see significant contrast increase — shadows darken, highlights brighten, and mid-tones barely shift. At full strength this is often too aggressive. Reduce to 25–50%. Notice how it makes the image feel richer without significantly shifting colour hue. This is the workhorse mode for contrast enhancement.
Layers panel → Mode dropdown → Overlay. Then adjust Opacity. -
05
Understand Neutral Values — Why They Matter
Create a new layer filled with pure white (#FFFFFF) and set its mode to Multiply. The layer becomes invisible — white is Multiply's neutral value and contributes nothing. Now fill the same layer with pure black (#000000) and set the mode to Screen — again invisible. This means: a white layer in Multiply mode and a black layer in Screen mode are both fully transparent. This is the mechanism behind many advanced compositing techniques — fill a layer with the neutral value, paint with black/white to add shadow/light, then set the blend mode.
Layer → New Layer → Fill with: White → Mode: Multiply (observe: layer disappears) -
06
Using Darken Mode to Remove a White Background
Create a new white layer (or paste an element on a white background). Set the mode to Darken. White pixels compare against the base layer — since white (255) is never darker than any other colour, the white disappears and only the dark content of the top layer shows through. This is the quick way to composite a scanned logo, line drawing, or ink texture onto a photo background without any selection work.
Create or paste element on white background → Mode: Darken -
07
Blend Mode + Opacity Interaction
Blend mode and opacity are independent controls that combine multiplicatively. A Multiply layer at 100% opacity produces maximum darkening. The same layer at 50% opacity produces half the darkening — as if the original Normal layer at 50% opacity were merged with a Multiply layer at 100%, then averaged. This means you can dial in exactly how much of the blend mode effect you want. Use opacity as the "strength" control for any blend mode.
Set any blend mode → use Layers panel Opacity slider to control effect intensity -
08
Soft Light for Non-Destructive Dodge and Burn
This technique uses Soft Light's neutral value (50% grey) to create a non-destructive dodge-and-burn layer. Create a new transparent layer. Fill it with 50% grey using Edit → Fill with FG Color after setting the foreground to #808080. Set this layer's mode to Soft Light. The grey layer is now invisible. Paint white on this layer with a soft brush at 10–20% opacity to lighten (dodge) areas; paint black to darken (burn) areas. None of the original image is changed.
New Layer → Fill with 50% grey (#808080) → Mode: Soft Light → paint white/black at low opacity
GIMP 3.2 note: GIMP's blend modes operate in Linear Light by default when using 32-bit float images. For 8-bit images (most JPEGs), this makes no visible difference. If you notice blend mode results look different from Photoshop tutorials, check Image → Precision — Perceptual (gamma) may produce more expected results for Overlay and Soft Light.
Open a portrait or landscape photograph. You will apply a cinematic colour grade using only blend modes and solid-colour layers — no colour tools required.
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A
Create a Multiply shadow layer
Duplicate the base photo layer. Set the duplicate's mode to Multiply, opacity 35%. This deepens the shadows and adds overall richness. Toggle visibility on/off to confirm the improvement. This is your "shadow deepen" layer.
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B
Add a colour tint using Screen
Create a new layer (Shift+Ctrl+N) filled with a warm orange colour (#F97316). Set its mode to Screen, opacity 15%. This adds a warm glow to the lighter areas of the image — the classic "golden hour" toning effect. Adjust opacity to taste.
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C
Add contrast with Overlay
Duplicate the base photo layer again. Set this duplicate's mode to Overlay, opacity 20%. This adds midtone contrast — the image should feel more punchy and defined. Stack all three effect layers and compare the result against the original by toggling the background copy's visibility.
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D
Build the non-destructive dodge/burn layer
Following Step 08 from the Core Technique, create a 50% grey Soft Light layer. Using a large, soft white brush at 10% opacity, gently paint over the subject's face or the lightest part of the image to lift it. Using a black brush at the same settings, darken the corners slightly. This is manual vignetting and selective brightening — in one non-destructive layer.
Expected result: A four-layer file: original base (hidden, untouched), a Multiply darken layer, a Screen warm tint layer, an Overlay contrast layer, and a Soft Light dodge/burn layer. The original pixel data has not been touched at any point.
Use the two-photo file from Session 2's stretch challenge (or open any two photos now). Your goal: blend them together convincingly using only blend modes — no selections, no masks.
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Try all six essential modes on the top photo layer
Work through Multiply, Screen, Overlay, Soft Light, Darken, and Lighten systematically. At 100% opacity first — observe the extreme result. Then bring opacity down to 30–60% and observe which combination produces the most interesting or believable result. Different image combinations will respond very differently to each mode.
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Find the combination that creates a double-exposure effect
A double exposure (two images blended together to look intentional) typically uses Screen at 60–80% opacity, or Soft Light at 50–70%. Try both. Consider: if one image is a portrait and the other is a landscape, which mode makes the landscape feel like it's "inside" the person?
Hint: Screen mode works best for double exposures when the background photo has lighter midtones. Soft Light works better when both images have similar exposure levels. Try swapping which photo is on top — the result changes dramatically.
Session 3 Review
- Blend modes replace the Normal formula with a mathematical operation on blend vs base pixel values
- Multiply always darkens; its neutral value is white (white disappears in Multiply)
- Screen always lightens; its neutral value is black (black disappears in Screen)
- Overlay combines Multiply (darks) and Screen (lights), with 50% grey as its neutral
- Soft Light is a gentler Overlay — smoother transitions, more photographic
- Darken and Lighten select channel by channel — they don't blend, they choose
- Opacity scales the strength of any blend mode — use it as the intensity dial
- Using Overlay at 100% opacity — almost always too aggressive, drop to 20–40%
- Forgetting that neutral values let layers "disappear" — white in Multiply, black in Screen, 50% grey in Overlay/Soft Light
- Applying a blend mode and then flattening — you lose the non-destructive advantage
- Confusing Darken (picks darkest channel) with Multiply (multiplies both channels)
- Not testing multiple modes — cycling through modes costs 2 seconds, and the best result is often unexpected
- Which blend mode always darkens, and what is its neutral value?
- How does Darken mode differ from Multiply mode?
- What colour do you fill a Soft Light layer with to make it "invisible" until painted on?
- In what scenario would you use the Lighten blend mode over Screen?
- What happens when you set a pure white layer to Multiply mode at 100% opacity?
- Session 4 begins Selection Mastery — the gateway to every targeted edit
- You'll learn Rectangle, Ellipse, Free Select, and Select by Color tools
- Selections and blend modes work together: you'll use selections to limit where a blend mode layer takes effect
- Prepare any image with clearly distinct regions (e.g. sky vs land) for the selection practice exercises
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01
GIMP Official Docs Authoritative reference for every tool, dialog, and preference in GIMP 3.x.
docs.gimp.org ↗ -
02
Davies Media Design Video walkthroughs specifically for GIMP 3.x — best free companion to this course.
YouTube ↗ -
03
GIMP Forums Community support for troubleshooting, plug-in questions, and workflow advice.
gimp-forum.net ↗