Particle overlay composer guide

Every control

Every control in the panel, top to bottom. The layer rows, the kind, gradient and motion buttons, and the preset list are made by the page as it loads, so each of those groups has one line here.

Most sliders store a finer number than they show. The range below is the slider's own; the number beside the slider in the tool is that value divided by 10 or 100, so a Bloom intensity of 40 reads 0.40. Where a starting value below differs from the one the tool shows when it opens, the tool's own number is the one it uses.

The sliders in the five kind sections change only the chosen layer. The sections from Subject image down change the whole scene.

Load and save

They stay at the top while the panel scrolls. Your pictures stay on this device for every lab tool until you press × on a tile; Reset puts the scene back and leaves them.

Image AButton: The subject: your picture, under every layer. Press it to open one from your device, or drop one anywhere on the page; two at once fill A and B. PNG, JPEG or WebP, up to 25 MB and 40 megapixels. It is kept on this device, never uploaded, and every lab tool that takes a picture opens with it until you press × on its corner. See WebP and JPEG.
SwapButton: Changes which tile Particle overlay composer uses, so a picture you added as B in another tool can be used here. When the other tile is empty, the scene has no subject.
Image BButton: A second kept picture. The composer lays one picture under the light at a time: the tile it is not using is dimmed and says Not used here, and pressing it only says so.
Save PNGButton: Saves the frame you see as a PNG. See PNG.
Save projectButton: Saves the whole scene as a project file to load later.
Load projectButton: Opens a project file saved by Save project and replaces the scene with it.

Layers

Layers add their light together, so their order does not change the picture.

Layer rowsFilled in by the tool: One row per layer; the chosen one has a coloured border. Press the kind button or anywhere on the row to edit that layer. Type in the name box to rename it. Hide and Show switch the layer off and on. Copy adds a copy of it with the same settings. Delete asks first, and the last layer cannot be deleted. The small line shows the gradient, and for a Meteor its motion and count, for Lightning its strikes a second and the most at once, and for the rest its count.
Add a layerFilled in by the tool: + Meteor, + Nebula, + Spark, + Dust and + Lightning each add a new layer of that kind with its own starting settings, named after the kind, such as Nebula 1. The new layer becomes the chosen one.

Layer kind

KindFilled in by the tool: Meteor, Nebula, Spark, Dust or Lightning turns the chosen layer into that kind. Its name, its gradient and whether it is shown stay; every other setting goes to that kind's start. See meteor layer, nebula layer, spark layer, dust layer and lightning layer.

Layer gradient

GradientFilled in by the tool: Twelve colour strips for the chosen layer: White, Meteoric, Phoenix, Ember, Ice burn, Aurora, Plasma, Sunset, Prism, Nebular, Twilight and Volcanic. Each tile shows its colours and names them. A meteor takes the colours from its head to the end of its tail, a spark from its birth to its end, a bolt along its length, a cloud across its width, and each dust mote one colour from the strip. See gradient.

Meteor physics

Shows only when the chosen layer is a Meteor.

MotionFilled in by the tool: How each meteor travels. Straight runs in a line. Curve bends its path to one side more and more. Wobble swerves from side to side. Decelerate slows down. Pulse makes the tail throb. Fan spreads the directions a little wider when the layer is scattered. Trail lag swings the tail away from the line of travel. Accelerate moves faster, up to two and a half times.
Physics intensitySlider · 0 to 100 · starts at 50: How strong the chosen motion is. Straight and Pulse do not use it. For Fan it takes effect when the layer is next scattered, for example with Restart.

Meteor shape

Shows only when the chosen layer is a Meteor.

CountSlider · 0 to 5000 · starts at 800: How many meteors the layer draws, up to 5,000.
Tail lengthSlider · 20 to 500 · starts at 120: How long each streak is, in pixels. See tail length.
Tail thicknessSlider · 3 to 60 · starts at 10: How wide each streak is. At 1.0 a streak is about 8 pixels across, soft at the edges.
Head boostSlider · 0 to 80 · starts at 20: Extra light at the front of each streak, so it reads as a hot tip. See head boost.
BrightnessSlider · 20 to 400 · starts at 100: How bright the whole layer is.
Fade rateSlider · 20 to 400 · starts at 140: How quickly a streak fades from its head to the end of its tail. Higher gives a shorter, brighter-tipped streak.

Meteor motion

Shows only when the chosen layer is a Meteor. Changing any of these scatters the layer afresh.

SpeedSlider · 20 to 800 · starts at 150: How fast meteors travel, in pixels a second.
Speed varianceSlider · 0 to 100 · starts at 30: How much each meteor's speed may differ at random from Speed. See variance.
AngleSlider · -180 to 180 · starts at 55: The direction meteors travel, in degrees: 0 is to the right, 90 is straight down, and minus 90 is straight up. See emission angle.
Angle varianceSlider · 0 to 180 · starts at 20: How many degrees each meteor may turn away from Angle, either way.
LifetimeSlider · 5 to 80 · starts at 25: How many seconds a meteor lives. It fades in at the start and fades out over the second half. See particle lifetime.
Lifetime varianceSlider · 0 to 100 · starts at 50: How much each meteor's lifetime may differ at random.

Nebula cloud

Shows only when the chosen layer is a Nebula.

CountSlider · 0 to 300 · starts at 25: How many clouds the layer draws.
SizeSlider · 40 to 800 · starts at 260: The size of each cloud, in pixels.
Size varianceSlider · 0 to 100 · starts at 60: How much each cloud's size may differ at random.
Drift speedSlider · 0 to 200 · starts at 14: How fast the clouds wander, in pixels a second. A cloud that leaves one edge comes back in from the other. See drift speed.
DensitySlider · 20 to 400 · starts at 120: How fine the swirls inside each cloud are. Higher packs in smaller, busier detail.
SoftnessSlider · 30 to 300 · starts at 150: How quickly a cloud fades from its centre. Higher makes a smaller, rounder glow; lower spreads it to its edge.
BrightnessSlider · 10 to 300 · starts at 70: How bright the whole layer is.
LifetimeSlider · 20 to 300 · starts at 100: How many seconds a cloud lasts before it fades out and returns.

Spark burst

Shows only when the chosen layer is a Spark.

CountSlider · 0 to 3000 · starts at 400: How many sparks the layer draws, shared among the emitters.
EmittersSlider · 1 to 40 · starts at 6: How many bursts the sparks fly from, each at a random spot. See emitter.
SizeSlider · 2 to 40 · starts at 8: The size of each spark, in pixels.
SpeedSlider · 40 to 800 · starts at 200: How fast sparks fly out, in pixels a second, in every direction.
Speed varianceSlider · 0 to 100 · starts at 50: How much each spark's speed may differ at random.
GravitySlider · 0 to 200 · starts at 15: How strongly sparks fall as they fly. At 0 they fly straight. See gravity.
LifetimeSlider · 10 to 300 · starts at 120: How many seconds a spark lives before its burst starts again.
Fade rateSlider · 50 to 800 · starts at 120: How quickly a spark dims over its life. See fade rate.
BrightnessSlider · 10 to 400 · starts at 100: How bright the whole layer is.

Dust motes

Shows only when the chosen layer is a Dust layer.

CountSlider · 0 to 8000 · starts at 400: How many motes the layer draws, up to 8,000.
SizeSlider · 5 to 100 · starts at 50: The size of each mote, in pixels.
Size varianceSlider · 0 to 100 · starts at 50: How much each mote's size may differ at random.
Drift speedSlider · 0 to 80 · starts at 6: How fast the motes wander, in pixels a second. They come back in from the opposite edge.
Twinkle depthSlider · 0 to 100 · starts at 55: How far each mote dims and brightens as it twinkles. At 0 it holds steady. See twinkle.
Twinkle rateSlider · 0 to 300 · starts at 20: How fast the motes twinkle. Each one runs at its own pace around this.
BrightnessSlider · 10 to 400 · starts at 90: How bright the whole layer is.

Lightning arcs

Shows only when the chosen layer is Lightning. Each bolt starts at a random spot and runs in a random direction. Bolts keep the scene's clock, so Time scale speeds them up or slows them down, and Restart clears them.

Strikes a secondSlider · 5 to 800 · starts at 60: How many new bolts appear each second, from one every 20 seconds to 8 a second.
Most at onceSlider · 1 to 24 · starts at 8: The most bolts on screen at once. When a new one comes, the oldest goes.
Flash lengthSlider · 5 to 200 · starts at 25: How long each bolt stays, in seconds. It flashes brightest as it appears, dims from there and is gone when this time is up.
JaggednessSlider · 0 to 100 · starts at 35: How sharply each bolt zigzags. See jaggedness.
Branch depthSlider · 2 to 8 · starts at 5: How many times each bolt's line is split into smaller zigzags. Higher gives a finer, more crooked line.
Branch chanceSlider · 0 to 60 · starts at 8: The chance that each point on a bolt throws off a thinner, dimmer fork.
ReachSlider · 100 to 1600 · starts at 400: About how long each bolt is, in pixels. Each one is between 60% and 120% of this.
ThicknessSlider · 5 to 80 · starts at 20: How thick each bolt is, in pixels. Forks are thinner.
BrightnessSlider · 10 to 600 · starts at 200: How bright the whole layer is.

Subject image

Your picture sits under every layer. Bloom, exposure, grading, lens effects and shake apply to it too; zoom does not move it.

CoverButton: Fills the frame with the picture and crops what does not fit. This is how it starts.
ContainButton: Shows the whole picture inside the frame, with dark bands where the shapes differ. See aspect ratio.
FillButton: Stretches the picture to the frame's shape.
OpacitySlider · 0 to 100 · starts at 100: How strongly the picture shows. At 0 it is gone and the dark ground shows.
Dim under particlesSlider · 0 to 100 · starts at 0: Darkens the whole picture under the light, so the layers stand out. At 0 the picture is as it is; at 1.00 it is black.
SaturationSlider · 0 to 200 · starts at 100: How colourful the picture is. 0 is grey. See saturation.
BrightnessSlider · 0 to 300 · starts at 100: How bright the picture is, up to three times.
Clear subjectButton: Takes the picture away, as × on the tile in use does: it is forgotten on this device too. Its settings stay.

Stars and time

Starts closed; tap its title to open it. The stars sit behind every layer.

Star countSlider · 0 to 300000 · starts at 40000: How many stars sit behind the layers, in steps of 5,000, up to 300,000. On phones and touch screens it stops at 60,000.
Star sizeSlider · 20 to 400 · starts at 100: How big the stars are. About one in twenty is drawn twice as big as the rest.
Star brightnessSlider · 10 to 400 · starts at 100: How bright the stars are.
Twinkle depthSlider · 0 to 100 · starts at 65: How far the twinkling stars dim and brighten. About half the stars hold steady whatever this is. See twinkle.
Twinkle rateSlider · 0 to 400 · starts at 100: How fast the twinkling stars twinkle.
Warm or coolSlider · 0 to 100 · starts at 50: The share of warm and cool stars. Towards 0 more stars are warm cream; towards the right end more are cool blue.
Time scaleSlider · 10 to 300 · starts at 100: How fast everything moves, from a tenth of normal speed to three times.

Bloom

IntensitySlider · 0 to 300 · starts at 40: How much glow is added around the bright parts. At 0 there is no glow. See bloom.
ThresholdSlider · 0 to 200 · starts at 55: How bright a part must be before it glows. Lower lets more of the scene glow, including a bright picture. See bloom threshold.
RadiusSlider · 5 to 200 · starts at 30: How far the glow spreads. The tool blurs a quarter-size copy of the bright parts twice. See Gaussian blur.

Exposure and tone map

ExposureSlider · 20 to 500 · starts at 120: How much all the light is multiplied before it is folded into screen range. See exposure and tone mapping.
VignetteSlider · 0 to 100 · starts at 35: How much the corners darken. See vignette.
Black pointSlider · 0 to 50 · starts at 0: Light up to this level becomes black, which deepens the dark parts.
White pointSlider · 50 to 300 · starts at 100: Divides the light before it is folded into screen range. Lower brightens the scene and sends the bright parts to white sooner.

Color grading

SaturationSlider · 0 to 300 · starts at 100: How colourful the finished scene is. 0 is grey. See saturation.
Hue shiftSlider · -180 to 180 · starts at 0: Turns every colour around the colour wheel by this many degrees. See hue.
ContrastSlider · 20 to 250 · starts at 100: Pushes the darks darker and the lights lighter, or the other way below 1. See contrast.

Lens effects

Chromatic aberrationSlider · 0 to 100 · starts at 0: Pulls the red and blue apart towards the edges, like a cheap lens. See chromatic aberration.
Film grainSlider · 0 to 100 · starts at 0: Adds fine noise that changes every frame. See film grain.

Camera

ZoomSlider · 50 to 200 · starts at 100: Moves the stars and layers closer to or further from the centre, from half to twice the size. The picture underneath does not zoom.
ShakeSlider · 0 to 100 · starts at 0: Shakes the whole frame, picture included, like a hand-held camera.
DriftSlider · 0 to 100 · starts at 0: Sways the whole frame slowly. The movement is small even at the top.

Playback

PauseButton: Stops the scene on the current frame; the button then reads Play. Changes you make while paused show when you press Play.
RestartButton: Starts the clock again and scatters every layer afresh. See restart.
Randomize layerButton: Gives the chosen layer a random gradient and changes a few of its settings at random: for a Meteor its motion, strength and angle; for a Nebula its detail and softness; for a Spark its gravity; for Dust its twinkle; for Lightning its jaggedness and forks. See randomize.

Presets

Starts closed. Type a name in the box under the list, up to 40 characters, and press Save or Enter.

Preset listFilled in by the tool: Your saved scenes, newest first, each with a small picture, its layer count and the date. Press a row or its Load button to load it; the tool asks before it replaces the scene. A picture you added shows under it only if the preset was saved with one showing. Delete asks, then removes it. See preset.
SaveButton: Saves the whole scene under the name in the box, with a small picture of the frame. A name already in the list is replaced.

Reset

The scene goes back to how the page opened: one Meteor layer and every setting at its start. Your picture and your presets stay.

ResetButton: Puts the scene back to how the page opened and starts the clock again. Your picture and your presets stay.