Base color is as it sounds the base color of a particular flower. It can often be seen on the back side of the flower more easily. Then your color descriptions are "suffused" or "diffused" or "overlaid" describing the appearance or existence of another color. Look at a lot of the awards of today or even the flowers posted here to see what I am talking about. You have already noticed that or you would not be asking.
I am thinking of a golden yellow Cattleya hybrid overlaid or suffused red. You can see this red shading on the surface of the Cattleyas petals for example. Those shadings, those color additions, have to be mentioned in the description. Sometimes the shading is pronounced, sometimes it is more subtle. The whole idea of a description is to describe a flower as completely and as accurately as possible AND in as few words as possible. You do not want people to have read a complete novel by the time that they read your description.
You have the award image right in front of you lots of times but you want the description to present an accurate and detailed picture of the awarded plant just in case the image is not there. At least in theory. As growers and hobbyists, those images point out the attributes of the plant in hand. So when it gets another award, one clone can be more accurately assessed against another clone. Gee Whiz, I hope that that made sense.
asking for Dr. E and other judges to comment.
Edited to add: "diffused" in my mind describes color on the surface that can be a little sparse. Sparse meaning you can easily see the base color of the flower coming through the diffusion. "Suffused" in my mind means more saturation, more solidness, to that shading color. Often times the suffusion does not allow for the base color to be seen through the suffusion.
The base color is the color of the flower without the (any) markings. It can be white, yellow, green or even red. As pointed, it’s usually discernible by the back of the flowers. Imagine a painting whose base color is the white canvas.
Overlay means the second layer of color over the base color. This is usually a SOLID coverage of a certain area of the flower. For example flamea pink overlay the half of the petals. In the painting analogy it would be the blue sky over the white canvas.
Suffuse (or flushed) means LIGHTER color over the base color in a certain areas of the flower. For example, a pink diffusion of color at the white petal tips, around the dark flamea overlay. In the painting, this could be the white clouds.
A picotee is the margin border of the flower part, usually described on the petal rims. It is usually a thin white border around the petal margin that demarcates from the base color (such as from pink petal base with a white margin). In the painting, this would be the frame.
The lip description is usually divided into 3 sections:
The inner throat, side lobes and midlobe (the large flat face in front).
The throat is usually described with a color (eg golden yellow in Cattleyas) with/out striations.
Side lobes are only described if different color that the midlobe (eg striated or solid dark lavender).
The midlobe is described with the overlay color by parts (sometimes up to 3 or more sectional colors) along with the color of the spots (or ‘eyes’). For example, midlobe white, striated magenta distally, with pink picotee, and two yellow eyes. In the painting analogy, it is like coloring a bird with the head as the throat, the body as the side lobes and the wings as the midlobe.
Thanks Dr. E!
I just thought of one thing else to say in response to My Green Pets question. We, as judges often take the "candidate plant" out into better light in order to assist us in evaluating color. Some rooms with their built in lighting do not provide adequate light when it comes to evaluating color. By getting out into sunlight or some other better light source, the true color(s) of the flower are revealed or seen more easily. That can be a negative or a positive thing. Usually positive. Natural sunlight can really make those colors POP!!!
It may be hard to appreciate the color of a flower from an image on a computer screen. It is much better to actually have the plant in hand.