I do apologise for the slightly off-topic thread, but in the absence of a general 'chat' section I didn't know where to post this.

I'm looking for advice on the legalities of using material for inspiration and reference, such as street photography that could be used to recreate a digital representation which contains more than a passing resemblance to the original photograph.

I initially thought using images found on 'royalty free' websites would be tolerated, but more often than not these images have usage fees (which begs the question what does 'royalty free' even mean?) so where do we go for our inspiration and reference sources? When is a digital painting that has been 'inspired' by someone else's photograph, a blatant copy? Where's the line?

Quite often with digital artist software, we see portraits of celebrities which have clearly been copied from a photograph, or simply the photograph has been used for manipulation, such as having an oil paint filter applied. Is this not copyright theft too?

Views and opinions very welcome.

[edit] A more in-depth search using terms like 'free to use images' garnered much better results, such as Pixabay, but I'd still be interested in others' views on the subject

Royalty free refers to copyrighted material, not to monetary value. in other words is free as in freedom not as in free "cupcakes", thus the service is what you are paying for, not the use of the picture itself.

The topic is vast, and if you want more details you really need to get some books about it, is just too much to cover and the internet is constantly stretching and changing the boundaries of what can be considered piracy or forgery.

For reference pictures, you can use anything, how often you see people on the streets selling hand drawn portraits of celebrities, have they go through a selling contract? nop. Now, if you use the actual picture and modify it, then you are in fact using someone else intellectual work (the photographer, not the celebrity on the portrait), and unless is something clearly and explicitly licence as cc-by, I wouldn't even venture with it.

We all use reference material. When check videos or blogs of well known artist, you will see their studios filled up with books, photos, illustrations, etc. (all of them likely copyrighted). yet inspiration and true reference aspects like angles, light, perspectives. etc. are obviously beyond the boundaries of the laws. Can you make and sell art from copyrighted material? you wouldn't be the first one, as you already notice, just check threadless and t-public (to mention two places among many, many more), but wouldn't you rather be original? but because of the enforcement been very week if not impossible at times. many of this places/people get along with all that and more.

A good habit is to mention sourced material, specially when you can't get in contact with the creator, it doesn't give you any right to copy it, but it will show that you are using it in good spirits.
Be cautions of the many "royalty-free" sites, need to check actual licence. you should look (if pictures and photographs) for cc-by or even cc-sa, if you are not looking to sell your art, also cc-nc or cc-nc-sa material is safe.

Just my thoughts

Thanks, Quiralta.

I actually think I hit the jackpot with Pixabay. They stress on their site that all images are free to use for whatever reason - even commercial. They even state that no credit is required. Also their search engine is very good and returns relevant results, unlike the 'royalty free' websites.