The "classical" way to change the sprite colour is to add two SPRITEINK commands at the start and at the end of the sprite code. Read more about that here.
Another way, which I implemented too in the last few years, is to link the AGD code to an external routine which is placed in memory after the game code and called through an ASM 205 (i.e. CALL in Z80 Assembly) instruction. This has the advantage of avoiding the (albeit very brief) changes in sprite colour edges which can occur with the classical method and allows the sprite to pass through platform blocks without them having all the same INK colour as the value of the first SPRITEINK. Allan Turvey (Mr highrise) demonstrated it in this video; the description also contains the link to download the source code of the routine.
About colours: remember that an inner bug in AGD will cause your game to display false colours under certain configurations, e.g. the ZX Vega. Luckily it can be fixed with a simple POKE instruction. More about that here.
Spectaculator does not emulate the ULA Plus. For that, you must use SpecEmu (latest version is the so-called "Christmas Edition" released in December 2018).
To remove the call to the ULA Plus code, assuming you wish to create a single-level, standalone game, you could try the tool made by xorrox, which can be downloaded from the thread I mentioned above. I haven't used it because it is of no help to me for the reasons I indicated in my reply, but you could find it useful.
Thanks. I'm not bothered about using ULAplus features. What I'm looking for is a way to fix the sprite flicker when you assign it a colour using SPRITEINK. In Mr Highrise's video he shows how to do this but he appears to be using AGD4.7. Is there a way to do this in 4.8?
Thanks, I'm new to developing on the Spectrum so it's just taking a bit of getting used to. I spent today looking at the ULAplus issues on the forum and I think I finally understand the problem and how to fix it.
Is this flicker of yours so severe? To be honest, it's difficult to notice, at least in my experience: see the Seto Taisho games and Doom Pit for instance, you can only see a hint of flicker, and rarely to boot. Yes the new colour routine by Allan makes sprites look even better but the old SPRITEINK technique works anyway.
Are you sure you are doing everything correctly? Could you post a sample file to run so that others could see what is going wrong?