Networked ITV - 1990s and before...

You would've thoguht so, but the output fot the opt outs was coming from Channel 4 in London, not the regional areas.

Possibly, or possibly on tapes pre-delivered to STV etc. I don't think C4 national distribution up until 1993 was capable of being split in this manner. The feed to Scotland, was the same feed that was Tee-d off to Central, Granada, YTV etc on its way up country.

What might have happened was C4 booked a contribution circuit to STV etc, and the programmes were played out from London and inserted locally that way ?

I've also been wondering about the S4C branded ITV Schools roto and clock, used 1997-1993, see below:

http://www.sub-tv.co.uk/pics/ITVSchools/itv_s4c_schools_1990.jpg

I doubt S4C were inserting their own junctions (except for opt-outs, some of which used the S4C roto and clock with no mention of ITV Schools), so were they receiving a feed of the Channel 4 junction without the '4' in the bottom corner? I can't see how they could key over the '4' logo with their own at every junction and have it look as tidy as it did.

Maybe they were doing it all themselves then, why do you doubt that the were doing their own junctions?

To be honest, it's quite possible they were. I've read elsewhere that 'the S4C logo was keyed over the Channel 4 logo', and although I doubt this was the case, that's why I thought they were taking the Channel 4 junctions. Looking again at that screencap, the typeface looks slightly different to that on Channel 4, although I've seen other examples where it looks identical. They were probably opting out of every junction, as they did from 1993 onwards, like you suggest.

There's a full explanation on TV Ark:

http://www2.tv-ark.org.uk/schoolstv/s4cschools_history.html

It was keyed over to produce the tapes that S4C played out to cover C4's junctions.

Did S4C work from a dirty feed of C4 or did they get clean feeds?

Thanks for that! So, the definitive answer!

I think 82 to 93 S4C had both C4's 'dirty' national feed, and a clean feed for sending programmes etc in advance, (some were timeshifted before they were seen on C4)

Certainly during the S4C Schools era (1993+) they were working from a dirty C4 feed; I have an example on tape of an S4C junction with a 'flash' of Channel 4 continuity at the end of the junction. I would imagine this would be the same during the ITV Schools 87-93 era.

I don't think there were actually many programmes 'simulcast' between Channel 4 and S4C back then (maybe the odd sports event or newsy programme) so they could get away with a dirty feed for these, probably the same sustaining feed sent to the ITV regions with everything there except ads. Of course, if they recorded a lot of programmes down the line from the 'live' C4 feed to play back later, I can see why a clean feed would be preferable.

As Marky said, if some programmes were clean fed to S4C prior to being transmitted on 4 (I think Brookside used to debut on S4C at 6pm) then surely this same feed could allow a programme to bypass C4 pres and go clean to S4C whilst actually being transmitted on 4?

Would they not have just sent tapes to Cardiff for Brookside? I would have thought tying up contribution circuits would be reserved for topical stuff that edited late?

I guess it depends how much stuff was actually timeshifted. If it was just the odd programme, like Brookside, then they could send tapes. Although ISTR a lot of programmes were common to both channels back then, so it may have been cheaper/easier to clean feed them across. Even now, timeshifted programmes on STV and UTV are normally recorded from the 'slightly-soiled' LNN/ITV1 feed.