Hi Walter, thank you for your reply.
We have not tried using Ultra Key. The current workflow has been used with the same system (on the machine) for 9 months of or so, with great success – the current issue has been happening for the last 4 weeks – although intermittently – that is to say some projects have had these artefacts, some have not.
BY ‘redactive’ I assume you mean a still from the final render? – I will post tomorrow when I get to the studio again.
The lines which appear and are exposing the greenscreen (which is grey, due to the workflow) are happening on truly random frames – with the odd occasion where they appear on the same frame after adjusting various parameters (as described in the initial post) – but mostly it appears on truly random frames.
Thank you again for your reply, I will post redactive frames tomorrow, althought the frames I have posted are redactive except the slide behind is removed showing only the alpha channel.
Best Regards,
Aaron