I know people tend to advise against having tattoos in other languages but I have given it a lot of thought and definitely want it doing. I am hoping to have a tattoo that translates into ‘strength (my own strength to face hardship and be courageous), love (love for myself, for others and nature/life) and light (whether this be Gods light, the light within, etc). I studied Latin at school but it was for a very short time and I wasn’t brilliant with all the various grammatical and feminine/masculine changes. Would ‘Fortitūdo, amor et lux’ be an accurate translation? I am female.
There can be (I'm sure) other possibilities, but I'd say that your ‘Fortitūdo, amor et lux’ is pretty good. I don't see any problem with your rendition.
This is by far not a complete answer, just some notes you may want to consider.
I read just a string of nouns. Translated to Latin, they won't magically gain any additional meaning (and may be even confusing, or end up in an unexpected amphibolia, if not carefully chosen). What is the message? Can you better explain what exactly do you want to say? Depending on that, you may want to put the words into a specific case. For example, if this is a list of your supposed properties, the Latin would not use nouns for that, rather adjectives and participles. If this is a list of instruments you employ, then it would be in ablative (“By strength etc.). Also, since you are creating a piece of art, so to say, consider the meter, so that the line reads as a verse.
Do not use macrons in writing (fortitudo, not fortitūdo). These are used only in dictionaries and Latin beginner books. There was a sign used in very early Latin writing, or rather inscriptions, to indicate long vowels, similar to our acute (ú), only more rounded, but it has disappeared by the time of the early Republic.
Some (very incomplete) vocabulary to ponder:
I am trying to exclude words with possible unexpected connotation, such as cupido, which can mean not only uncurably passionate love, but also lust or greed.
- vis = strength, great force (“strength to lift 100 pounds”).
- virtus = strength and courage; also virte. This was inseparable for the Roman ear from its root vir, “a man”, though, probably not what you want, as I understand from your comments to @varro's answer. However, it was applied also to women in a positive sense.
- robur = strength as robustness. To the Latin ear, sounds inseparable from the name of the oak tree, robor, a tree that has retained its sacred connotation from the Indo-European religion (think the Yggdrasil) even in Roman times.
- fortitudo = strenght, courageousness.
- firmitudo = firmness, stability, “soft but unyielding” strength. (Less common word.)
Note that Latin is not very gung-ho on abstracts, so all these words in -[i]tudo and -io belong to a more formal and abstract writing (think a philosophical tract). And “strenght” is, naturally, an abstract. So consider rewording here, as I already suggested above.
In the order from raw passion to high, non-sexual esteem:
- ardor = passionate, uncontrollable love.
- amor = a lover's love, love in general.
- dilectio = respectful love and affection, e. g. to a dear friend or brother. (Less common).
- caritas = charity, esteem.
Assuming you are asking for the noun for the antonym of dark, not the adjective opposite of heavy, and of the nouns meaning “light” an abstract (“Sun casts a bright light”), not a lightning fixture (“I turned the reading light on”):
- lux = natural light, daylight.
- lumen = any light, such as provided by a lamp or torch.