How to get gel DMX values for ETC fixtures

Issue

I need to get DMX values for certain gels to mix colors on a third-party control device with ETC fixtures.

Download the "MyETC: Photometrics" app for iOS or Android.
Open the app, select a fixture from the list and tap on the Color dropdown menu.
In the top row of the popup window, change to "Gel Picker" and select the desired color, click on "Apply"
Swipe to the right; here you will find DMX values as well as a spectral curve for the selected color.