---
title: "Photo Editing Blend Modes Explained"
description: "Multiply is arithmetic, not a mood. How base and blend values combine, the four modes worth knowing, why layer order changes the result, and why opacity is separate."
canonical: "https://freeaigeneration.com/en/guides/photo-editing-blend-modes-explained/"
robots: "noindex"
lang: "en"
---

# Photo Editing Blend Modes Explained

Multiply is not a mood. It is a multiplication of channel values, and once you have seen the arithmetic behind it, the mode menu stops being a list of names to try.

That is the approach here: photo editing blend modes explained from the numbers up rather than from an interface, because the formulas are the same in every application that has them.

## Base values and blend values

Compositing happens on numbers. Normalize a channel to the range 0 to 1, where 0 is black and 1 is white. Each pixel has a value from the layer below — the base — and a value from the layer above — the blend. A blend mode is a formula that takes the two and returns a result.

It is values rather than colors that matter here. The formula runs separately on red, green and blue, which is why a Multiply blend on a saturated color looks the way it does.

## The four modes worth knowing cold

Normal replaces the base with the blend wherever the blend layer is opaque. A black pixel over white gives black, and nothing underneath survives.

Multiply multiplies. White is neutral because anything times 1 is itself; black is decisive because anything times 0 is 0. Fifty-percent gray over fifty-percent gray gives 0.25, so the result is a quarter-strength gray where you started with half.

Screen is the inverse operation: 1 minus (1 minus base) times (1 minus blend). Black is neutral, white is decisive, and fifty-percent gray over fifty-percent gray gives 0.75 — a much lighter result from the same two inputs.

Overlay and Soft Light choose between Multiply and Screen according to the base tone, darkening where the base is dark and lightening where it is light. Soft Light applies that choice gently; Overlay applies it as a contrast push.

## Opacity is a separate dial

A blend mode answers how two values combine. Opacity answers how much of that combination is kept.

Take the Multiply case at fifty percent opacity over a fifty-percent base. The multiplied value is 0.25 and the untouched base is 0.5, so a half-and-half mix lands at 0.375 — roughly 38% gray, about 96 in 8-bit terms. The mode did not produce a mid-gray; the opacity dial did.

That is why turning opacity down is not the same as choosing a gentler mode. One mixes the result back toward the backdrop; the other changes the formula.

## Order changes the answer

Multiply and Screen are commutative: swapping the two layers gives the same result, because multiplication is multiplication whichever side you start from.

Overlay is not. It inspects the base to decide whether to darken or lighten, so the same two layers in the opposite order produce a different image. When a look depends on Overlay, the stack order is part of the recipe, and reordering layers later will change it.

## Where a mode sits among the other decisions

Three questions, three different mechanisms. A mask decides where a change applies. An adjustment layer decides whether a change is still reversible. A blend mode decides how values combine. It is common to need all three at once, and they fail independently.

That independence is also a diagnostic. A layer that does nothing at all is usually hidden by its own mask rather than affected by the wrong mode; a layer that is far too strong is an opacity question before it is a mode question.

## Mistakes worth avoiding

Treating a mode as an opacity setting is the first, and the arithmetic above shows why it does not work.

Using Screen to brighten a photograph without checking the highlights is the second: values near white have nowhere left to go, so the lightest areas flatten into each other.

Expecting a mode to travel inside a flat export is the third. A PNG holds composed values; the mode belongs to the layered document, so the receiving application has no mode to re-apply.

One boundary is worth stating plainly, since this is arithmetic rather than a menu tour. The [Photo Editor](/en/tools/photo-editor/) publishes a layer stack with masks and adjustment layers, but its feature description does not include a blend-mode list, so check the layer panel of whichever editor you have open rather than assuming a mode is there.

The coverage question, which is what most masked blends are really about, has [its own guide](/en/guides/how-layer-masks-work-a-beginners-guide/), and the reversibility question belongs with [adjustment layers versus direct edits](/en/guides/adjustment-layers-vs-direct-edits-which-should-you-use/).