Psychic art is practiced by some mediums, those who have developed the gift. They often use it alongside their mediumship and clairvoyance, but in some cases they work with a partner who may give clairvoyance whilst the artist draws.
The medium makes a link to a spirit, and then uses their clairvoyance and clairsentience, to capture the appearance. As the portrait appears, clairvoyance adds to the picture and good communication can take place. It can be very spiritually rewarding.
The medium who uses automatic writing will usually work alone and later show the prose, or sometimes music, which they have created. They have to tune into their spirit guide and let their hand and pencil be controlled by the guide without hinderence.
Psychic art seems to be a gift that is disappearing. There do not seem many mediums who are dedicated enough to develop such gifts.
Along with automatic writing, psychic art is a gift that was used a lot in the Victorian era. It can be a lonely development as often it is a gift best developed in solitude.
Those who practice automatic writing often do it late at night when they can be alone and undisturbed. Psychic art can be developed in a circle, but again, solitude often helps.
Once the gifts are developed enough to share, a small circle is perhaps the first place to demonstrate, before going fully public.
A very famous psychic artist was Coral Polge, a spiritualist medium who is now on the higher side of life. She drew wonderful portraits and there are several books about her work. I was fortunate enough to be able to see her work on many occasions.