Paint has changed to lighter

[marb]

We painted our room a couple of years ago and I saved the tin as it was still mostly full. It was kept sealed in the loft. When I touched up parts of the wall that had marks I found to my horror (after stirring tin) that all the touched up parts look paler in comparison. I waited a few days to see if it was temporary and they are still pale. It is very obvious. If we can't get the same paint again we will have to do the room again. I have kept paint for years after and never had this problem with others when touching up.

Is there a reason why paint would change to this degree?

 

[Pigeon85]

All paints change colour after time just some more than others, if its just the one wall that needs touching up then you would get away with doing just the one wall in that colour

 

[dcdec]

You have to remember that your existing wall colour has had a couple of years of wear and tear, microscopic dirt and grime and dust and deterioration. Some degradation of materials in the paint from the tin could also have occurred. Both mean you'll never get a match unless as already said you paint the whole wall. Best in future to use durable matts so they can be washed clean.