LinearLens / DaVinci Resolve DCTLs

Let intense highlights contaminate the image before tone mapping tames them.

Linear Bloom builds highlight spread and veiling glare while source brightness is still represented linearly.

Demonstration

Three real render comparisons.

Each wipe uses one neutral frame from the demo set and the matching LinearLens output for this tool.

Example 01 / Linear Bloom

Neutral demo frame 01
Linear Bloom render for demo frame 01
BEFORE AFTER

Example 02 / Linear Bloom

Neutral demo frame 02
Linear Bloom render for demo frame 02
BEFORE AFTER

Example 03 / Linear Bloom

Neutral demo frame 03
Linear Bloom render for demo frame 03
BEFORE AFTER

The science

Why this behaves differently from the obvious alternative.

Bloom and veiling glare come from light scattering inside the optical system and around very bright image-forming energy. The amount of contamination is related to the source itself, not merely to how bright that source looks after tone mapping.

Working before the development or display transform keeps very bright scene values distinct. That gives the bloom stage access to the intensity relationship that a later glow effect has largely lost.

Why it matters

Against a glow effect

Glow is often keyed from already rendered highlights and can produce a visibly composited halo. Linear Bloom is intended to behave as part of the image-forming chain, before those highlights have been compressed into a narrow display range.

Why it matters

Veiling glare as well as bloom

A broader low-frequency component can let strong sources lift their surrounding field instead of creating only a tight halo.

Linear Bloom

Gentle lens bloom

Particularly useful for practical lights, windows, specular highlights, candles and stage lighting where a conventional post-render glow can feel detached from the source.

Design principle

Highlight-derived spread

The stage responds to the underlying scene-linear intensity before the display rendering stage.

Design principle

Local + broad contamination

Tighter bloom and broader veiling behaviour can be balanced for different optical characters.

Design principle

RGB light relationship

The operation acts on linear RGB values rather than a gamma-compressed representation.

Design principle

Small-source handling

Designed to remain useful around compact practicals and specular highlights as well as broad bright areas.

How to use

Make a linear optical block, then continue into the grade.

The DCTL does not need to own your colour management. Put the transforms around it: camera source into a suitable linear RGB representation, LinearLens in the middle, then into the colour-development space you want to grade in.

01 Camera source Log / RAW development input
02 Transform to linear Keep a suitable working gamut; make light scene-linear
03 Linear Bloom Diffusion / bloom / CA / MTF / defocus
04 Transform to development space For example DWG Intermediate or another grading space
05 Camera + colour + film work Balance, creative grade, film emulation, output rendering

The important placement is the highlighted block: LinearLens belongs after you have made the image linear, and before the development, grading and film-look stages that intentionally reshape tonal values.

Linear in

Use a Colour Space Transform, ACES transform or equivalent to get the image into a scene-linear RGB representation while retaining an appropriate gamut.

DCTL block

Place diffusion, bloom, CA, MTF sharpening or defocus here. If you use several, this is the optical-character section of the chain.

Develop after

Transform onwards into the space used for camera matching, primary colour, creative looks and film emulation. Those stages can then work on an image whose optical character is already established.

Lifetime licence
Single DCTL

Also available

All five for £100.

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