So far most of the references to fabric have been related to the top or outer fabric of a garment. But as a garment is a composite of different types of material reference must be made to the other materials, often hidden, which are also part of the garment. Failure to ensure that linings and interlinings are compatible in performance with the outer fabric can absolutely nullify careful selection of the main fabric. This seems an obvious statement but is it surprising how often incompatibility occurs in commercially made garments. Often this is caused by false economy in the use of inferior materials on the lines of what is hidden does not matter. But equally it is plain that many manufacturers who take great care in selection of main materials do not feel that equal care is necessary in selection of subsidiary materials. Those who do know that it plays in time and trouble and proof of this is shown in the way in which specifications are laid for all materials which go into durable press garments. The main fabric, linings, interlinings, trimmings, sewing threads, zip-fasteners and even buttons must reach a certain standard of performance, particularly in respect of high temperature curing which is necessary. This is admittedly an extreme case but it illustrates a principle, which has over and over again been shown to be well worth extending. For example it would seem obvious that a garment designed to be regularly washed would need to be made from a fully shrunk, or otherwise shrink resist material. It should seem equally obvious that there is little point in using interlinings and lining in such a garment which have received no anti shrink treatment at all because the distortion caused by their shrinkage can cause distortion of a seam so that a non-shrink sewing thread should also be part of such a garment. If a garment is made from drip dry material intended as an easy care garment it might again seem obvious to state that linings and interlinings should be drip dry also, but this requirement is often ignored as if the outer fabric had the power to some how communicate its properties to the other materials. Stretch fabrics need special consideration as to whether some garment areas should be prevented from stretching or matching with equally stretchable interlinings. Non-woven and fusible interlinings can also raise compatibility problems. The correct weight and type should be carefully selected. Most of the manufacturers publish booklets giving advice on their qualities because the majority of the complaints they have dealt with were the result of incorrect quality selection rather than faulty material, qualities are washable, some are not, some fusible types can be dry cleaned satisfactorily, some cannot. The use of fusible interlinings raises certain difficulties. Some types are treated with a resin, which will discolour a white top material and therefore are not suitable for all fabrics. Some man-made fiber materials are dyed with dyestuffs, which 'sublime' under heat and the use of heat to fuse interlinings can cause a color charge, which may or may not and the use of heat to fuse interlinings can cause a colour charge, which may or may not reverse when the fabric cools. A number of fabrics shrink in dry heat or steam. It is impossible to cover every aspect of compatibility but the user of fabrics should be thoroughly aware of the need for all components of a garment to behave similarly under reasonable conditions.