One of the most beautiful examples of needlepoint I've ever seen is a three-panel screen that stands in a Scottish castle, made in 1835. It's surprisingly contemporary in design.

Each panel has a large Chinese pot from which a flowering tree is growing. But it is the coloring that is so bold and exciting. The pots stand on a black-and-white marble floor and the background for the trees is a clear yellow. The flowering trees are white, coral and jade green with little birds in brilliant colors among the branches.

How marvelous it must have been for those stitching ladies to forget for a while the gray Scottish mists as they buried themselves in a sea of color.

Interestingly enough, the background is worked in a stitch resembling a woven tapestry that, as you probably know, was the inspiration for needlepoint itself. At the base of the design, the stitches are worked in little cushions or squares diagonally over the mesh of the canvas. These cushions get smaller as you go up, ultimately blending into tent stitch, the smooth tapestry like stitch of regular needlepoint, known variously as continental stitch or petit point.

One of the most important things tapestry weavers have taught us -- and it's obviously a lesson well learned by those Scottish ladies -- is that color contrast in needlepoint design is everything. A great deal of subtle soft shading can be lost, often making the overall effect muddy. Don't be afraid to be bold. Choose the colors you like together and once you've chosen, throw a group of them down on the floor. If they look well together, keep them, if not, discard and eliminate until you have a homogenous group.

Most people have an innate color sense that they use instinctively when they see a completed thing, but when it comes to choosing for themselves they become hesitant and selfconscious. One good thing about needlework is that you can choose from existing colors.

Just like tapestry weavers, though, you must have a colored "cartoon" or picture to work from, either a painting, a sketch with colored crayons or cut-out paper shapes. If you're designing your own piece, you will be working on plain canvas with an outlined design and can fill in the colors following the cartoon. Then you don't cover up the colored part as you work and can always use your cartoon as a guide.

Apart from color, the stitches are fascinating and make the work go quickly. That background stitch is called mosaic and is quite simple to do (see diagram). To incorporate background stitches into your needlepoint, the best plan is to make a little "sampler" -- collect a variety on a strip of canvas you can refer to as you go.

Mosaic is one effective stitch, reverse tent is another. Work one row of tent stitch in one direction, the second row beside it slanting the opposite way. After several rows, you will see this gives you the effect of stocking stitch in knitting. Since this is a strong stripe effect, you can work it horizontally or vertically.

In the black-and-white mosaic flooring on the Scottish screen, the ladies worked another form of mosaic stitch. This is a series of slanting satin stitches forming "pillows" or squares alternated with an equal sized square of tent stitch.

When you're working these background stitches, always complete your tent-stitch sections first. Then start from the center of an open background section, bringing the stitches close up to the completed stitching. Fill in those awkward little places where background and the completed design areas meet with tent stitches in the background color. It is much easier to do this last, so you can see exactly where you have to fill in. Another tip -- never start a new area of background a little distance away from the first and expect them to join up! The chances are they won't, and you'll be tearing your hair out -- and your stitches, too!

Q: I have recently finished a piece of needlepoint and I want to know how to clean and block it. Blocking and framing seems to be an expensive proposition. Can you tell me how to make a finished product?

A: Cleaning can be done in numerous ways. Stale white bread rubbed on the surface is good for picking up loose dust and soil. Goddard's spot cleaner I find useful. It comes in a spray can and if you test it first to make sure it is safe to use, then you can go ahead.

But perhaps the best method is to block your work on stretcher strips and, while it is wet, clean it by rubbing the back of the needlepoint with a cake of Ivory soap. Rinse well and, of course, use cold water.

Before blocking, test for colors that might run by pressing damp blotting paper on the needlework. If color shows up on the blotting paper, you mustn't attempt to wet it. Have it dry cleaned instead. If it is colorfast, however, stretch your work out square on artist's stretcher strips, using a heavy-duty staple gun.

Then wet your stretched needlework with cold water, rub it with Ivory soap, rinse, and let it dry in its own time.

A frame can be added inexpensively by buying wood, chrome or enamel strips to fit around the stretched needlework.

Q: What's the best way to remove the blue print outline on crewel embroidery. There is a pattern I would like to make, but it has a butterfly imprinted on the material that I do not want in the picture.

A: There seems to be no way to remove the blue print outline on crewel embroidery. Designs are always printed in permanent ink, so that the color of the outline will not run into the embroidery thread or the background linen and make it look dirty. If anyone knows a way to remove the outline, please write and tell us.

If you want to remove the butterfly, I can only suggest embroidering some other figure or appliqueing a piece of fabric over the place where the butterfly is.

An alternative is to transfer your design to a new piece of linen, without the butterly. In that case, you have several choices. Sarah paper, which is available in art supply stores, provides an excellent way of transfering designs on cloth. It costs about $5 for a 12-foot roll, but is also available in smaller sheets. It's a wonderful kind of carbon paper that transfers easily and clearly and will wash right out.

If you can't find it, dressmaker's carbon is a good substitute, since it won't smudge as regular carbon does. Dressmaker's carbon is available in notion and fabric stores.

There's another method of transferring that is excellent if you are going to stretch your work on a round frame or use stretcher strips. You outline your design boldly with a black marker. Tape it closely to the back of your stretched linen. Then shine a gooseneck lamp or any flexible light behind it. The black outline will be clearly silhouetted on the cloth and you will be able to trace it easily with a fine-tipped permanent marker.