ΔE 19.8, loose: different enough that you should pick on purpose. Splinter Green is noticeably darker, more saturated than Viridian Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Splinter Green is noticeably darker, more saturated than Viridian Green.
The same difference applies the other way round: Viridian Green is noticeably lighter, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Viridian Green on the colour wheel See Splinter Green on the colour wheel
All matches: Viridian Green equivalents · Splinter Green equivalents