On this page
Chapter 18 · Every blend mode
Blend modes are the least understood part of any image editor and the part that repays understanding most. A blend mode is a formula: it takes the colour of the layer below, called the base, and the colour of the layer above, called the blend, and produces a result. Photopea exposes twenty-seven of them, and the same list appears in three places — the layer panel's blend dropdown, the options bar for painting tools, and the Layer Style dialog — so learning the list once pays off in all three. This chapter lists every mode with the formula it implements and the situation it is actually good for, because a mode you cannot predict is a mode you will never reach for.
Two numbers govern the whole system. The base colour is written as a and the blend colour as b, both normalised to the range zero to one. The result is written as r. Opacity then interpolates between the base and the result, so a mode at 50% opacity is halfway between doing nothing and doing the full formula. That single fact explains most of the confusion around blend modes: changing opacity is not the same as changing the formula, and a mode that looks wrong at 100% often becomes exactly right at 30%.
The Normal group
| Mode | Formula | Use |
|---|---|---|
| Normal | r = b | The default; the blend colour simply replaces the base where the layer is opaque |
| Dissolve | r = b where a random threshold is exceeded, else a | Produces a stochastic dither at partial opacity; the only mode that creates hard-edged noise rather than a smooth mix |
Dissolve is the one mode in this group that behaves unexpectedly. At 100% opacity it is identical to Normal; as opacity drops it does not fade, it thins, replacing pixels randomly rather than blending them. That makes it the correct mode for a spray-paint or film-grain effect and the wrong mode for anything that needs to look smooth.
The Darken group
| Mode | Formula | Use |
|---|---|---|
| Darken | r = min(a, b) | Keeps whichever colour is darker per channel; removes light areas from the blend layer |
| Multiply | r = a × b | Always darkens; white becomes transparent, black stays black; the workhorse for shadows, textures and high-pass sharpening |
| Color Burn | r = 1 − (1 − a) / b | Increases contrast while darkening; saturates shadows hard and clips aggressively |
| Linear Burn | r = a + b − 1 | Darkens by addition; stronger and flatter than Multiply, with more clipping |
| Darker Color | r = whichever of a, b has lower luminance, taken whole | Like Darken but operates on the composite rather than per channel, so it never shifts hue |
Multiply is the mode most people use most often and it is worth understanding precisely: because white multiplied by anything is that thing, a white background in the blend layer disappears entirely. That is why a texture photographed on white can be dropped onto a layer, set to Multiply, and used immediately. Color Burn is the aggressive sibling — it produces rich, saturated shadows but destroys detail there, so it belongs at low opacity or masked into a specific region rather than applied globally.
The Lighten group
| Mode | Formula | Use |
|---|---|---|
| Lighten | r = max(a, b) | Keeps whichever colour is lighter per channel; removes dark areas from the blend layer |
| Screen | r = 1 − (1 − a)(1 − b) | Always lightens; black becomes transparent, white stays white; the inverse of Multiply |
| Color Dodge | r = a / (1 − b) | Increases contrast while lightening; blows highlights to pure white quickly |
| Linear Dodge (Add) | r = a + b | Lightens by addition; the correct mode for combining exposures or adding light glows |
| Lighter Color | r = whichever of a, b has higher luminance, taken whole | Like Lighten but composite-based, so hue is preserved |
Screen and Linear Dodge are the two lightening modes worth memorising. Screen is gentle and never clips in the way Color Dodge does, which makes it the right choice for a soft glow or for lifting an underexposed layer. Linear Dodge is additive and therefore physically meaningful: adding two light sources is addition, which is why it is the mode used when stacking star fields or combining multiple exposures of the same scene.
The Contrast group
| Mode | Formula | Use |
|---|---|---|
| Overlay | Multiply if a < 0.5, Screen if a ≥ 0.5 | Boosts contrast while preserving the base's luminance; the default for high-pass sharpening and texture overlays |
| Soft Light | A gentler Overlay with a smooth curve | Subtle contrast and colour; the safest mode for dodging and burning on a 50% grey layer |
| Hard Light | Multiply if b < 0.5, Screen if b ≥ 0.5 | Overlay with the layers swapped; much harsher, and useful for lighting effects |
| Vivid Light | Color Burn if b < 0.5, Color Dodge if b ≥ 0.5 | Extreme contrast; clips heavily and is best at low opacity |
| Linear Light | Linear Burn if b < 0.5, Linear Dodge if b ≥ 0.5 | Extreme and linear; produces hard, graphic results |
| Pin Light | Darken if b < 0.5, Lighten if b ≥ 0.5 | Replaces midtones selectively; good for a grunge or posterised look |
| Hard Mix | Each channel forced to 0 or 1 | Reduces the image to eight colours; a posterisation effect, not a blending effect |
The distinction between Overlay and Hard Light is the one that trips people up: Overlay decides based on the base layer, Hard Light decides based on the blend layer. Practically, that means Overlay preserves the underlying image's light and dark structure and pushes the overlay into it, while Hard Light lets the overlay dictate where light and dark fall. For texture work, Overlay is almost always right. For a lighting pass — a gradient meant to look like a light source — Hard Light or Linear Light is right, because the gradient itself is the light.
Soft Light on a 50% grey layer is the classic non-destructive dodge-and-burn setup. Because 50% grey is the neutral value for Soft Light, painting white on that layer lightens and painting black darkens, with no effect where the layer stays grey. It is the cleanest way to sculpt light on a photograph without touching the pixels underneath, and it is the technique most worth adopting from this chapter.
The Inversion group
| Mode | Formula | Use |
|---|---|---|
| Difference | r = |a − b| | Subtracts and takes the absolute value; identical colours cancel to black, and it is the basis of difference-keying |
| Exclusion | r = a + b − 2ab | A softer Difference with less contrast; good for a washed, inverted look |
Difference is genuinely useful beyond its novelty value. Because identical pixels cancel to black, subtracting a blurred copy of an image from the original with Difference isolates the high-frequency detail — a different route to the same result as High Pass. It is also the mode used to check alignment between two versions of an image: any misregistration shows up immediately as a coloured ghost.
The Component group
| Mode | Formula | Use |
|---|---|---|
| Hue | Hue of b, saturation and luminance of a | Recolours without changing brightness or saturation; the correct mode for a colour wash over a photograph |
| Saturation | Saturation of b, hue and luminance of a | Changes colour intensity only; a Saturation layer at 0 desaturates without greying |
| Color | Hue and saturation of b, luminance of a | Full recolouring that preserves the base's light and shade; the best mode for hand-colouring |
| Luminosity | Luminance of b, hue and saturation of a | Changes brightness only; the inverse of Color, and the mode for a luminance-based sharpening or contrast pass |
These four are the most conceptually clean modes in the list because they operate on the three components of colour separately. Color over a greyscale base is how hand-colouring works: the base supplies all the shading, the blend layer supplies all the hue. Luminosity is the mirror image and is the reason a high-pass sharpening layer is usually set to Luminosity rather than Overlay — it sharpens without introducing colour fringing, because the hue and saturation of the base are left untouched.
Pass Through
Pass Through is not a blend mode in the formula sense. It is the default mode for a layer group and it means the group does not flatten its contents before blending; each child layer blends with whatever is below the group as if the group were not there. Change a group from Pass Through to Normal and the group is composited internally first, then blended as a single unit. The difference is visible whenever a child layer uses a mode like Multiply: under Pass Through it multiplies with the background, under Normal it multiplies only with its siblings and then the result sits normally on the background. This is the single most common source of "why does my adjustment layer not affect the layer below" confusion, and the answer is almost always that the adjustment is inside a group set to Normal rather than Pass Through.
Choosing a mode without memorising formulas
Twenty-seven modes is too many to hold as formulas, but they collapse into five intentions, and knowing the intention is enough to pick a starting point. If you want to darken, start with Multiply and move to Linear Burn or Color Burn if it is not strong enough. If you want to lighten, start with Screen and move to Linear Dodge if you need more. If you want contrast, start with Overlay and move to Soft Light if it is too harsh or Hard Light if it is too weak. If you want to cancel or compare, use Difference. If you want to change one component of colour without disturbing the others, use the Hue, Saturation, Color and Luminosity group.
That mapping covers every practical case, and the remaining modes are refinements within those five families rather than separate tools. The one exception is Hard Mix, which is genuinely its own thing and is best understood as a posterisation effect that happens to live in the blend menu.
Closing the inventory
With this chapter the item-by-item inventory is complete. The reference has now walked the menu bar item by item in chapter 13, the tool rail and its options bar in chapter 14, every panel and panel control in chapter 15, every dialog in chapter 16, every filter in chapter 17 and every blend mode here. That is the full surface of the editor: if a control exists in Photopea, one of these six chapters describes it.
What the inventory also establishes, by exhaustion rather than by assertion, is where the surface ends. There is no 3D menu, no timeline panel, no print-production dialog and no scripting API beyond the plugin bridge. Those absences are documented properly in chapter 19, which is now the correct next stop for anyone deciding whether Photopea fits a particular job.