ND Filter EV vs Digital Gel

This is a calculator for photographing using ND (Neutral-density) filters with any number of stops. ND STOPS lets you set the exposure without ND filter in a blue field, and see the result below. EV ALTERNATIVES gives you a dual combo alternatives of ISO, APERTURE and SHUTTER SPEED SWEET SPOTS is not always accurate, but in many cases lenses has its sweet spot at about 40% up on the aperture range. SETTINGS lets you choose which stops you want to see in the ND STOPS PAGE and at what EV (exposure value) interval in all pages. To see more apps like this, go to www.discobajas.com

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.