Interfacings are an essential part of any type of tailoring. Before I begin with a series of instructional posts, we need to understand what these different types are. I hope this will help you with purchasing the right structure for your garments!
This is recommended for lightweight women's suit jackets in the 1930s and 1940s. Often these instructions call for wigan or muslin, but most muslins available today are much lighter weight and not nearly as stiff as they once were. Today wigan is sold for interfacing the sleeve hem.
It has a decent amount of spring for being very lightweight, coming in around 1/2".
It is, however, easily finger pressed into a crease along both the warp and weft.
It is fairly loose in it's weave, but is well-sized. It would prevent shifting of the fabric and keep it from stretching too much along the bias.
The listing for this fabric also termed it "buckram", though we'll discuss the proper definition for that term below. This is a very lightweight non-fusible interfacing meant not for coat collars, but for shirt collars and cuffs.
It has about 3/8" spring, but honestly has little fight in it.
Creasing is incredibly easy, which is good if you want to stitch it into the seam allowances of collars and the like.
Very sheer and light, the weave is moderately open.
Heavy Weight Hymo
This does very well for the body interfacing of heavy weight textiles. It's a viscose and polyester blend. It also comes in natural color, which you'll see an example of in the medium weight below.
This has about 3/4" spring and will fight back. In fact, it has so much spring that I cannot finger press it at all on either grain.
The weave is fairly tight, the threads themselves are thick.
Medium Weight Hymo
This is appropriate for body interfacing of most weights of fabrics. It's something I use fairly universally for bodies and collars. It's very good for anything involving pad stitching, though it's propensity to fraying means I wouldn't use it for a backing on pocket openings. A combination of cotton, rayon, hair, and polyester.
It has a good 5/8" spring. It won't crease with the weft folded over, though the warp threads are lighter weight and can be folded easily.
It's woven tightly with the weft threads being dominantly heavy.
Often referred to as Holland linen today, this is a very light-weight linen that has been pounded flat in a complex process that gives it a permanent glazed look. This was sometimes used in men's 18th century garments, but I keep it around for lining women's shoes and use the scraps to back buttonholes and pocket slits.
The spring is only around 3/8". It doesn't fight back much and can crease.
The weave is tight and the fabric is very heavily structured, but light. This means it has almost no give, but won't be bulky.
This is a tightly woven linen that I stiffened using gum tragacanth. Some historic sutlers carry this from time to time ready made, but it's very easy to make yourself (and therefore cheaper). You can put on more coats of the gum to get the stiffness you want. I love using this for pocket slit backing.
This has about 1/2" spring.
It is possible to crease this fabric, but it's easy to smooth out the fold as well.
The weave of this will depend on the linen chosen. I tend to look for a good, tight weave over a heavy weight.
French Collar Canvas
While meant today for pad-stitching into stiffer coat collars, it is surprisingly similar to historic buckram, both made from linen.. Though, it is very expensive, so it's not as well suited to do large fronts out of.
This has almost 3/4" spring.
It does crease, but again straightens out well.
Still lightweight, but you can see how even the threads are. It doesn't allow for any movement along the bias or stretch.
This textile is used in layering for the body interfacings or anywhere that a great deal of spring is needed. The stiff hairs mean that the edges must be dealt with and it's best sandwiched between layers so nothing works through to the outside later.
This has about 5/8" spring, but the fight is enormous. It was hard to get it to bend this much to be pinned.
The hairs only run along the weft, so the warp is much softer and this can be folded that direction.
This is a straight tape (bias is available) that is used along the edges of interfacings and the crease of the collar to prevent any stretch. It's much lighter weight than twill tape and won't add bulk. It's edges are "raw", but it's not prone to fraying without effort.
You'll notice I didn't include any of the iron-on style of interfacings. I really strongly believe in the quality of hand-sewing and the manipulation of the fabric that can be done in that process. Machine work is not as easy to maneuver, but still above iron-on. Those types of interfacings are used in most modern mass-produced suits, but with equipment that works the garment into a pre-set curve and shape while setting. I don't like that result much, but it's very difficult to even get that achieved without the equipment. That being said, I do have some of the cheap iron-on interfacing you can get at local fabric stores around. I use it for backing small areas of fabrics that are very prone to fraying around problem areas like buttonholes, pocket openings, or other notches and slits.