Durham had resumed the day on 406 for six after Mark Stoneman and Ben Stokes had guided them to a strong position after an early double strike by Ryan Sidebottom.
Collingwood was unbeaten on 74 overnight but he added just seven more runs before becoming Sidebottom's fourth wicket of the innings when he was lbw, his 81 coming off 152 balls.
Mark Wood joined Richardson at the crease but fell for 20.
Richardson was unbeaten on 58 at the interval with Jamie Harrison on 31 in a 61-run stand.
Maurice Chambers finished with five wickets as Sussex lost their final three men for 33 runs as their hopes of a late title charge suffered a blow against Warwickshire at Edgbaston.
They had started well on Wednesday before losing seven wickets for 74 runs with Chris Jordan's unbeaten 58 providing some stability to close on 278 for seven.
However, Jordan moved on to 61 when he was bowled by Keith Barker, his third victim of the innings, and with no further runs on the board, Will Beer fell for 31, lbw to Chambers.
Steve Magoffin and James Anyon inched the score on to 311 before the former became Chambers' fifth victim.
However, Magoffin engineered the perfect response by reducing the hosts to two for two, removing both Varun Chopra and Ateeq Javid for ducks.
Warwickshire were 19 for two at lunch.
Piyush Chawla was unbeaten on 111 as Somerset continued the fightback they started on Wednesday against Middlesex at Lord's.
Chawla resumed on 58 not out and he wasted no time in setting about the the hosts' attack, reaching his hundred off 139 deliveries in 187 minutes, a ton that included four sixes and 10 boundaries.
Alfonso Thomas was far more cautious, his 37 coming off 124 balls as Somerset made lunch on 413 for eight.
In Division Two, a strong performance by the Lancashire tail saw them reach 421 against Hampshire at Southport.
Luke Procter made 66 but it was the two tail-enders Glen Chapple and Simon Kerrigan who really stood out.
Chapple was the last man out for 63 off just 65 deliveries, including five boundaries and two sixes, while Kerrigan was unbeaten on 62 off 70 balls.
Hampshire were five without loss.
There was no play between Gloucestershire and Essex at Bristol with rain preventing any action in the morning session.
Leicestershire lost their final three wickets for just three runs against Worcestershire as Alan Richardson claimed a hat-trick to finish with five for 57 at Grace Road.
Resuming on 270 for seven, the hosts made four runs before Ollie Freckingham (26), Matthew Hoggard (nought) and Alex Wyatt (nought) were all removed in successive deliveries
However, Leicestershire hit back before lunch, Hoggard claiming the scalps of Matthew Pardoe (two) and Daryl Mitchell (23) with Ben Raine taking out Moeen Ali (25) as Worcestershire reached lunch on 65 for three.
Glamorgan reached lunch on 180 for two in their match against Northamptonshire at Wantage Road.
Stephen Peters (61) and James Middlebrook (59) were the men out, both falling victim to Michael Reed.
Derbyshire were 75 for two at lunch on day one of their clash with Surrey at The Oval.