How should I sign my painting?
The primary reason for signing your painting is to affirm that you created it. Likewise, when you sign a print you are indicating that you approve, and you declare that it wasn't a trial print, or a galley proof.
There is only one hard and fast rule concerning your signature: sign only an original.
All other decisions related to signing a painting are a matter of personal choice.
What can be signed?
You can sign any watercolor painting that you have personally created.
Do not sign a painting that is a copy of another artist's photograph, painting, instructional book, DVD, or workshop. A painting based on another artist's work is a "derivative" work. It is based on someone else's creativity. Don't create the impression that it is your own work by signing it.
The problem is that all art is derivative to some extent. All original ideas come from somewhere. The challenge for each artist is knowing where to draw the line between their own creations and those based on the work of others.
Some watercolorists reference the original artist when they sign the piece. They simply sign their name and then under their name they write "after (the artist's name)." This acknowledgment is sometimes placed on the back of the painting. Other artists give credit for their inspiration in the title of the piece. Consider Picasso's paintings "Las Meninas (after Velazquez)" and "Le Dejeuner sur l'herbe (after Manet)."
Here's a different approach to consider.
Don't worry about the nebulous distinctions between a copy, a derivative work, or a remotely related painting. Instead, extract the essence of the previous work and build your new creation based on that essence. Don't ask yourself, "If I change 4 or 5 elements of the original, can I claim it as my own?" Instead, reduce the original to its fundamental shapes and build something new. Once you have reduced a reference work to its essence, manipulate that essence to suit your artistic vision.
What name should I use?
Should I use my full name, first initial and last name, last name only, first name only, initials only, maiden name or married name, a pseudonym, a personal mark, a geometrical design, a stamp or chop, a monogram, or a symbol?
All of these have been used by artists in the past.
If Picasso had signed his full name, it would have been Pablo Diego José Francisco de Paula Juan Nepomuceno María de los Remedios Cipriano de la Santísima Trinidad Ruiz y Picasso. At first, he signed his name P. Ruiz Picasso, then he changed his signature to Ruiz Picasso, and finally to just Picasso.
On one occasion, Picasso refused to sign an authentic painting, explaining to the woman who had brought it to him, "If I sign it now, I'll be putting my 1943 signature on a canvas painted in 1922. No, I cannot sign it, madam, I'm sorry."
Rembrant's signature also changed over time.
Rembrant Harmenszoon van Rijin's earliest signature was the monogram "RH" meaning Rembrant, the son of Harmen. Later, he added an "L" (presumably for the city of Leiden where he was born). Then he added a surname "RHL-van Rijn". In 1633, he added a "d" to his name and began signing his work with only his first name, "Rembrandt."
Salvador Dali's signature changed so many times that one of his assistants wrote a book showing 678 variations.
Albrecht Dürer signed his works with a monogram. James McNeill Whistler also signed his paintings with a monogram but with a twist. He wanted to distance his art from the written word, so he transformed his initials, JW, into a butterfly. Whistler's butterfly signature evolved over time. Shortly after he sued art critic, John Ruskin, for accusing him of merely throwing paint at the canvas, Whistler added a long tail and a stinger to his butterfly signature. Some thought this was the perfect signature for an artist with a gentle, sensitive nature and a provocative, feisty spirit.
Georgia O'Keeffe didn't sign her paintings at all; she didn't think she had to. She thought people would be able to tell they were hers because of what she painted and how she painted it.
Where should I sign the painting?
It all depends on your purpose.
If you want the signature to be visible, allow enough room for the mat. (Some artists sign near the edge, because they want to sign the painting but they want their signature hidden by the mat).
When a signature is visible on the painting, it has traditionally been placed towards one of the bottom corners.
Artists who use initials, a monogram or a symbol will often sign their full name on the back.
What are some methods of signing a painting?
Artists have signed their paintings with a variety of tools including a detail, script or rigger brush, a graphite pencil, a Micron marker, a Pigma brush pen, a quill pen, or a Rapidograph pen filled with ink or watercolor.
Some sign their name with an archival watercolor pencil then lightly stroke over it with a damp brush to activate the paint.
Others have used a stylus. Before starting to paint, they sign their name where they'd like it to appear, pressing down into the watercolor paper so their name is indented into the paper. When they paint over it, the paint settles into the indentation causing the signature to be the same color but darker than the surrounding area.
A stylus can also be used after an area has been painted but is still shiny-wet when the indentation is made.
In addition, you can use a stylus after a painting has dried. Simply paint over the area where you want the signature to appear, sign your name with a stylus, and then quickly blot up the fresh paint. (The paint will remain in the indentation).
Some artists make three quidelines (top of uppercase, top of lowercase, and bottom) in very light pencil and then pencil in the signature. They paint over the pencil letters, let it dry, and then erase the pencil marks that are still visible.
Finally, some artists lift their signature. After a painting has dried, they sign their name with water, wait a few seconds, blot, and rub briskly with a terry cloth towel to lift as much paint as desired.
What color should my signature be?
The answer to this question once again depends on your purpose.
Some artists want the signature to blend with the rest of the painting. They will choose one of the colors already used in the painting.
Others want the signature to stand out. Judy Morris, Joseph Zbukvic and Bob Ross always sign their paintings in red, regardless of the colors used in the painting.