Should I use primer after caulking before using emulsion?

[b3taman]

Hi, I never seem to have too much success using ordinary tube decorators caulk - it's dead easy to use, but when for example I use it on a ceiling for plasterboard line cracks and then go over it wiith emulsion it always shows through as a slightly darker line.
Should I be using an oil based primer over the caulking lines first before the emulsion?
I've done a forum search for this problem but the results refer mainly to cracking and not the slightly different appearance which I always seem to get.

 

[Pigeon85]

In future open the crack up a little and use filler

 

[b3taman]

Thanks Pigeon 85 - I know that filler will be fine for this - my query really was how people avoid having a distinctly darker colour when painting white emulsion directly over caulk lines - I'm sure I can't be the only person that has this problem.

 

[misterhelpful]

I know what you mean, but as caulk is really intended to be used for perimeter pointing (corners and around frames, etc) it doesn't usually stand out that the paint may dry slightly darker/lighter and it can just appear as a shadowline.
If you use caulk in the middle of a wall/ceiling, then it is almost always likely to be noticeable. An oil undercoat may help, but as suggested, standard fillers are far better in that kind of situation.

 

[b3taman]

Ah! - I see - caulk isn't meant for ceiling cracks etc? - I didn't realise this.
Think I'll stick to ordinary filler except for joints and edges then.
Thanks.