Yes cnd unit, and agree could be coz different machine,but not cost effective to have different machines for each system, thinking about it I could be due new bulbs think about 5 months old, just seems weird it's only the very dark colours everything else perfect :-/
It's because dark colors are very pigmented and the UV must penetrate right through the dark color to cure correctly, so hence why our bulbs need to be working correctly and using the correct UV light.
If you have the CND lamp for your Shellac services that great but I would check with Artistic colors if they give the ok for their colors to be cured in the CND lamp.
Every lamp is different and every good branded system is tested using their own branded lamps unless they say it's ok to use any UV light with their system, so if this is happening with your Artistic colors, it could be that the CND lamp is not suited to this system.
Yes, it also could be that you are applying your layers too thick and should try thinner layers but I would definitely check on the lamp situation to see if Artistic give the ok for the CND lamp to be used.
Too many techs are saying "Oh but my xx system is curing fine in my xxx lamp" but to visually look at a cured nail, you can not tell if it has actually cured correctly and long term this can have dire affects on the client from un-cured product.
This is why we trust the science and testing behind our good brand systems cause they are the ones that have done all this and can tell us if the system can be cured in any uv lamp or their own specific branded lamp, cause not all lamps are made equal.
I just think it's something to check into to be on the safe side that's all. You don't need to cause a permanent allergy in a client and find out it's because you were not using the recommended uv lamp for that system and have the client make a claim against you and then you have your insurance nil and void because you were using the wrong lamp.
I know it's expensive to have different lamps but your service charges should incorporate all these expenses and with most systems, you get your money back pretty soon on the cost of the lamp if you charge correctly for the service