Désolé que je ne peux pas aider plus…I haven’t touched Premiere since 1990s! The never changing rule: Entertainment Technology Debug Question One: What else has changed? Entertainment Technology Debug Question Two: What else has changed? Of course, you wonder if DCP O Matic has changed…? When I google Premiere update color shift – many answers, some recent, many old. =-=-= The right color space depends on the capabilities of the equipment that you are using, the client’s release format, and importantly for you, the archive format. A library has value only if it keeps up with current trends. For example, a VHS format and color space has little value today – it is unwatchable and cannot be upgraded easily or well. And more than one streaming service is demanding P3 4K minimum. All trends are toward more and better pixels: How soon 2020? The best that the client can afford today! But you are the client!!! The trend in the standards world is toward a high grade mezzanine format for archiving and a lot of metadata for different iterations and evolutions. SMPTE ST2065 – Academy Color Encoding Specification (ACES),and ST 2067 – Interoperable Mastering Format (IMF) detail the entire path from production to various forms of exhibition…and those standards continue to be worked on. I don’t have a specific answer to “Right Color Space for Premiere” but it seems that the answer is a constantly improving workflow for deliverables that are going to be under constant pressure for better and interchange software that will help advance that. Regards in return…Charles