The Art Nouveau design style of the 20th century VS. The Psychedelic design style of the 1960’s

Art nouveau design style:

It could be recognized to be the first new decorative style of the twentieth century and is described by 2 different styles of look. There are: elongated and curvy looks vs. plain and linear lines. However, this style of art always have such as birds, flowers and insects but also include women and fantasy creatures, etc as its main keys of style. Therefore, that's why it's used most in decoration and architecture.
Art Nouveau is said to response the Industrial Revolution since while new materials and technologies are used, it stressed on handcrafting instead of machine manufacture.

Poster by Alfons Mucha

Casa Batllo in Barcelona, Spain, designed by Antonio Gaudi

An Art Nouveau architecture

Urbanc house, Ljubljana

Psychedelic design style:

It is an art style inspired by the prevalence of hallucinatory drugs, especially LSD, with typical designs featuring abstract swirls of intense colors. There are a great number of things that always stick with this kind of art: bright and highly contrast colors, repetition of motifs, fractal patterns, and so on. Besides that, psychedelic art is composed of music, drugs, art, literature and hippie activities. They all turned into an outstanding combination of fine art and commercial art technique.

Wes Wilson and Psychedelic Art
By Fiona Clark

Oversoul by Alex Grey

Psychedelic guitar design

Personally, I think Art Nouveau and Psychedelic Art are similar at some points such as shapes, lines, curves, etc. However, colors used in Art Nouveau is much more muted but comfortable for our eyes to look at, while Psychedelic Art artists tend to use highly contrast colors to present their ideas. Moreover, there always has abstract swirls of intense colors and exotic patterns in Psychedelic artworks. On the other hand, Art Nouveau uses typical flat decorative patterns, combined with organic forms or floral graphics. Besides that, Art Nouveau designers like to use formal and antique fonts, while in Psychedelic Art, complex and graphics fonts are more popular.

Reference:

http://en.wikipedia.org/wiki/Image:F_Champenois_Imprimeur_Editeur.mucha.jpg
http://www.bluffton.edu/~sullivanm/spain/barcelona/gaudibatllo/facdet2.jpg
http://html.rincondelvago.com/files/8/7/8/000188780.jpg
http://commons.wikimedia.org/wiki/Image:UrbancevaHisa-Ljubljana.JPG
http://en.wikipedia.org/wiki/Art_Nouveau
http://www.bbc.co.uk/homes/design/period_artnouveau.shtml
http://en.wikipedia.org/wiki/Psychedelic_art
http://www.leahfaust.com/fausthaus_blog/wes_wilson.jpg
http://www.iamshaman.com/galleries/gray/images/image_01.jpg
http://www.cffguitars.com/psychedelicTOM.jpg