The signed limited edition titles have been produced using photo lithography
ie. When published each one is absolutely identical
and there is
Original etchings and old silkscreen prints produced by hand have created the idea that some work ie. low numbers in the edition are more valuable
This is due to the printing process where the plates are inked, and it is suggested that earlier numbers could be slightly clearer than the later ones.
Some sales people can unwittingly confuse a client by implying one number is better or more valuable than another
This is completely incorrect.Conservation framing and 'museum' UV blocking glass was not used much in the 1960's and '70's
Prints were often attached to the mount with sellotape (not acid free tape used frequently today)
The print was often stuck onto board using glue and a heat press
Its life from publication to the present day is the most important factor of any print
If it has survived the last 50 years and is in good condition with strong original vibrant colours
then it will probably be fine for the next 50 years, as long as it is kept away from strong sunlight and damp
Normal 2mm. picture glass cuts down UV by 50%, so with double glazing it is generally quite safe
UV blocking glass can be expensive (at least twice the price of 2mm. glass), so if you wish to be 100% sure it is a good option
Museum glass cuts most of the UV and has non-reflective properties too
This gives a superb effect, but comes at a cost.
Museum glass for a good sized picture could be £200-300