Digital Gel
Extract & apply gels digitally
$3.99 · Designed for iPad. Not verified for macOS.
Meter a fixture bare and through a gel. Digital Gel turns the difference into a color ratio you can apply to any light and dial straight into the console.
Digital Gel is a precision color tool for gaffers, DPs, and lighting programmers.
Meter a fixture bare, then meter it again through a gel. Digital Gel captures the
difference as a color ratio — a "digital gel" — that you can apply to any other
light and read back as CIE x,y coordinates to enter on the console.
WHAT IT DOES
• Extract a gel from two spectrometer readings (bare + through the gel).
• Apply that gel — or a stack of gels — to any target light.
• Correct: work backwards and cancel a filter you can't take away.
• Refine any result against a real meter reading until it lands.
• Get the result as x,y for the console, plus CCT, tint (in CC and Δuv), and
mired shift.
• See everything on a CIE 1931 chromaticity diagram with the Planckian locus,
color-temperature ticks, and optional Rec.709 / P3 / Rec.2020 gamut overlays.
CANCEL WHAT YOU CAN'T REMOVE
Not every filter is a choice — a tinted window, a diffusion frame, a practical's
own glass. Meter your fixture with it in the way, and Correct solves for the x,y
to set the fixture to so the light lands where you wanted it after the glass. It
states the move in mired and CC as well, so the answer is just as usable if you
reach for a CTB and minus green instead of the console — and it tells you when a
filter is simply too strong to cancel.
Saturated filters don't treat an LED fixture quite the way the math expects, so
Correct flags them and lets you Refine: meter the result through the filter, enter
the reading, and dial the next value. Refine learns how your fixture and filter
actually respond, and closes in within a few passes.
BUILT FOR THE SET
• Enter light as x,y, as a color temperature (5600), or temperature with tint
(3200 -2).
• Save a library of gels and custom sources; mark favorites; search your list.
• Calibrate a fixture that doesn't hit the color it's told to, so Apply's
numbers land where you mean them.
• Touch and hold any result to copy its x,y.
• Choose CAT02 (recommended) or raw XYZ adaptation math.
• A transmission read of each gel's red / green / blue balance at a glance.
• Universal: one column on iPhone, two panes on iPad portrait, three in landscape.
PRIVATE BY DESIGN
No account to create, and no data collected. Your gel library syncs between your
own devices through your private iCloud — nobody else can see it — and with iCloud
switched off the app is entirely local.
Digital Gel works in chromaticity, so it matches color points, not full spectra —
when metamerism matters on set, trust your meter, and let Refine close the gap.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Refine — close the gap between the math and the meter.
One pass of Correct is spot-on for mild filters, but a saturated one — a deep cyan,
say — can land visibly off on an LED fixture. Now you can meter the result through
the filter, enter the reading, and Refine gives you the next value to dial. From the
second pass it measures how your fixture and filter actually respond, so even strong
filters settle in a few passes. Strong filters are flagged up front, and each pass
shows how far off the last reading was, so you know when to stop.
Calibrate a fixture — for lights that don't quite hit the color they're told to. Dial
a value, meter what comes out, and Apply compensates for it. Save a profile for each
fixture you use.
Also new: touch and hold a result to copy its x,y — the Copy button is gone — and the
refine and calibration tools now sit neatly under each result.
The developer, TIMO TAPIO HAAPASAARI, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- TIMO TAPIO HAAPASAARI
- Size
- 1.9 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Timo Haapasaari

