View source for Photismic chords

'''Photismic chords''' are [[Dyadic chord|essentially tempered dyadic chords]] tempered by the photisma, [[324/323]].

There are two triads, nine tetrads, seven pentads and one hexad as 2.3.17.19 subgroup [[19-odd-limit]] essentially tempered chords.

The two photismic triads are in inverse relationship: 
* 1–24/19–17/12 with steps of 24/19–9/8–24/17; 
* 1–9/8–17/12 with steps of 9/8–24/19–24/17. 

For tetrads, there are three palindromic chords and three pairs of chords in inverse relationship. The palindromic chords are
* 1–9/8–17/12–19/12 with steps of 9/8–24/19–19/17–24/19; 
* 1–17/12–3/2–17/9 with steps of 17/12–18/17–24/19–18/17; 
* 1–18/17–9/8–19/16 with steps of 18/17–17/16–18/17–32/19. 

The inversely related pairs of chords are
* 1–9/8–17/12–3/2 with steps of 9/8–24/19–18/17–4/3, and its inverse
* 1–18/17–4/3–3/2 with steps of 18/17–24/19–9/8–4/3; 
* 1–24/17–3/2–19/12 with steps of 24/17–17/16–18/17–24/19, and its inverse
* 1–17/16–3/2–17/9 with steps of 17/16–24/17–24/19–18/17; 
* 1–24/19–17/12–3/2 with steps of 24/19–9/8–18/17–4/3, and its inverse
* 1–18/17–19/16–3/2 with steps of 18/17–9/8–24/19–4/3. 

For pentads, there are one palindromic chord and three pairs of chords in inverse relationship. The palindromic chord is
* 1–9/8–17/12–3/2–19/12 with steps of 9/8–24/19–18/17–18/17–24/19. 

The inversely related pairs of chords are
* 1–17/16–9/8–17/12–3/2 with steps of 17/16–18/17–24/19–18/17–4/3, and its inverse
* 1–18/17–4/3–24/17–3/2 with steps of 18/17–24/19–18/17–17/16–4/3; 
* 1–24/19–4/3–17/12–3/2 with steps of 24/19–18/17–17/16–18/17–4/3, and its inverse
* 1–18/17–9/8–19/16–3/2 with steps of 18/17–17/16–18/17–24/19–4/3; 
* 1–9/8–19/16–3/2–19/12 with steps of 9/8–18/17–24/19–18/17–24/19, and its inverse
* 1–18/17–19/16–3/2–19/12 with steps of 18/17–9/8–24/19–18/17–24/19. 

Finally, there is a palindromic hexad,
* 1–18/17–4/3–24/17–3/2–19/12 with steps of 18/17–24/19–18/17–17/16–18/17–24/19. 

[[Equal temperament]]s with photismic chords include {{Optimal ET sequence| 12, 14, 26, 29, 38, 65, 77, 89, 101 and 113 }}.

[[Category:19-odd-limit chords]]
[[Category:Essentially tempered chords]]
[[Category:Triads]]
[[Category:Tetrads]]
[[Category:Pentads]]
[[Category:Hexads]]