The more you know about the poster the better history you have to tell and at the same time, you get more listeners. People like to hear about provenance and this gets the poster to be more interesting.
So how can you find out more about the poster?
First of all you can ask the seller what he knows. Ask where the poster comes from, if it has been in use and where. If you need more information, you have many sources you can try.
Learn about the artist. Learn about the company that published the poster, learn about the printer and learn what the poster is promoting. All this will increase both your knowledge and your love for your poster. At the same time, the more knowledge you have the better price you get for it, if you want to sell it. Provenance adds value to your posters.
If you are unable to date a poster, you have many sources you could research.
Research old adverts and magazines, timetables and even old luggage labels. Old brochures and adverts can be very useful when it comes to dating a poster with no printing date. Sometimes the posters are unsigned or has an unreadable signature but the artist can be found anyway.
V&A - magazines
I have spent many hours in the library in Victoria and Albert Museum in London. They have a large collection of vintage posters and they have a great library. The library with their large collection of magazines and publications has always been a useful source for research.
Now are parts of this valuable resource available online! It has been online for some time now but not many know of it. You can find it here: V&A - magazines
Some sources to have in mind:
- Poster books
- Old product catalogs
- For travel posters:
- Postcards collections
- You can find many good web resources about shipping lines, railroads and air lines
Some museum poster collections to research
- Victoria & Albert Museum, London UK
- Swiss National Library
- The Wolfsonian–Florida International University
- Library of Congress
- London Transport Museum
- National Railway Museum UK
- MAAS Collection (AUS)
- And of course many others
Good luck researching! Knowledge is king! Feel free to comment!