I just read up more, they say not to use sun factor cream on new tattoo just yet
I'd say call and ask them what their advice is.
To be fair, most aftercare instructions are based around what works without causing any infections or loss of colour. Sun creams are known to cause skin reactions in lots of people, acne etc. so will be bad for a tattoo. However, if you know your skin is ok with a particular cream use it when in the sun to prevent sun damage to your tattoo, and more importantly, your skin. As long as you wash the area after sun exposure, and then follow your normal aftercare you should be ok.
To be fair, most aftercare instructions are based around what works without causing any infections or loss of colour. Sun creams are known to cause skin reactions in lots of people, acne etc. so will be bad for a tattoo. However, if you know your skin is ok with a particular cream use it when in the sun to prevent sun damage to your tattoo, and more importantly, your skin. As long as you wash the area after sun exposure, and then follow your normal aftercare you should be ok.