To setup custom indices on a Vista, see below. In this example we will setup a 24 mm vial for Saybolt.
Go to Essentials WORKSPACE menu > COLOR SCALES > INDICES, and click CUSTOM INDICES.
In CUSTOM INDICES dialog, select SAYBOLT and enter the cell pathlength, click ADD to create this index. Then click APPLY.
In COLOR SCALES/INDICES dialog, scroll down the indices list, and check this new custom index and click APPLY.
The new custom index will be shown in Color Data Table view.