Phosphoric iron,
Iron with sufficient phosphorus present to increase the hardness of the metal. As well as increasing the hardness, phosphorus also increases the rate of work hardening of the metal, and its brittleness. In 17th-18th century Britain, phosphoric iron was referred to as ‘cold-short’, since it tended to crack during cold forging, but was preferred for nailmaking due to its hardness. Phosphorus also increases the drawability of low-carbon wrought iron, phosphoric iron being used for the wires of musical instruments (Goodway 1999 [JHMS, 33.2, 104-5] The presence of phosphoritic iron may be revealed under the microscope by excessive grain size (when little or no carbon is present) and/or ghost structures when some carbon is present in the metal.
Iron with sufficient phosphorus present to increase the hardness of the metal. As well as increasing the hardness, phosphorus also increases the rate of work hardening of the metal, and its brittleness. In 17th-18th century Britain, phosphoric iron was referred to as ‘cold-short’, since it tended to crack during cold forging, but was preferred for nailmaking due to its hardness. Phosphorus also increases the drawability of low-carbon wrought iron, phosphoric iron being used for the wires of musical instruments (Goodway 1999 [JHMS, 33.2, 104-5] The presence of phosphoritic iron may be revealed under the microscope by excessive grain size (when little or no carbon is present) and/or ghost structures when some carbon is present in the metal.
Photographic Emulsion,
In the engraved roller industry known as a ‘light-sensitive varnish’. It is usually made of a branded PVA (polyvinyl alcohol) emulsion added to a solution of ammonium bichromate. One way, using Stensol (a proprietary brand which is sold unsensitized), is to make a stock solution with 6 per cent sodium bichromate and mix one part stock solution to five parts Stensol.
In the engraved roller industry known as a ‘light-sensitive varnish’. It is usually made of a branded PVA (polyvinyl alcohol) emulsion added to a solution of ammonium bichromate. One way, using Stensol (a proprietary brand which is sold unsensitized), is to make a stock solution with 6 per cent sodium bichromate and mix one part stock solution to five parts Stensol.
Photogravure,
The process by which an ‘ engraving’ is produced in a metal plate or cylinder by means of light acting on a sensitised surface and the resultant image then being etched in acid. Conventional gravure cylinders all have cells or ‘dots’ of the same width but varying depth so that they hold either more or less ink, thus producing varying tones f one colour. One of the main methods of printing transfer paper.
The process by which an ‘ engraving’ is produced in a metal plate or cylinder by means of light acting on a sensitised surface and the resultant image then being etched in acid. Conventional gravure cylinders all have cells or ‘dots’ of the same width but varying depth so that they hold either more or less ink, thus producing varying tones f one colour. One of the main methods of printing transfer paper.
Photomechanical (techniques),
A style of textile printing (known in France as picotage) used in the eighteenth century. A series of brass pins were driven into the surface of the block which was then used to produce a pattern, either as background or as shadowy shapes of such things as leaves.
A style of textile printing (known in France as picotage) used in the eighteenth century. A series of brass pins were driven into the surface of the block which was then used to produce a pattern, either as background or as shadowy shapes of such things as leaves.
Phulkari,
Lit. flower work. Shawls of khaddar cloth embroidered by Punjabi women in floss silk, leaving much of the background cloth unembroidered,done in satin stitch over counted threads on coarse madder or indigo-dyed home-spun cotton fabric. Also Ref. Bagh.
Lit. flower work. Shawls of khaddar cloth embroidered by Punjabi women in floss silk, leaving much of the background cloth unembroidered,done in satin stitch over counted threads on coarse madder or indigo-dyed home-spun cotton fabric. Also Ref. Bagh.
Pichhavai,
The pigment-painted temple hangings or pichhavais of the Vallabhacharya Sampradaya, a Krishna sect in Rajasthan and Gujarat, are hung behind the image of the deity. The term pichhavai is a Hindi word, literally meaning ‘of behind’ (pichha - back and vai - of), which well describes the hanging’s function.
The pigment-painted temple hangings or pichhavais of the Vallabhacharya Sampradaya, a Krishna sect in Rajasthan and Gujarat, are hung behind the image of the deity. The term pichhavai is a Hindi word, literally meaning ‘of behind’ (pichha - back and vai - of), which well describes the hanging’s function.
Piecing,
The joining of pieces of fabric to make a larger textile. The top layer of “patchwork” quilts is pieced before being quilted.
The joining of pieces of fabric to make a larger textile. The top layer of “patchwork” quilts is pieced before being quilted.
Pigment,
Colour which is not fully absorbed as a dye, but which binds to a surface when incorporated in an emulsion. In indigo's case the dried pigment becomes a dye when dissolved in the dye vat with Alkalis and a reducing agent.
Colour which is not fully absorbed as a dye, but which binds to a surface when incorporated in an emulsion. In indigo's case the dried pigment becomes a dye when dissolved in the dye vat with Alkalis and a reducing agent.
Pigment,
Fine, colored powder that makes paint when combined with various liquid mixtures, such as water and a binding agent.
Fine, colored powder that makes paint when combined with various liquid mixtures, such as water and a binding agent.
Pigment printing,
The printing of fabrics with opaque pigments that lie on the surface of the fabric instead of being absorbed into the fibres. Such pigments should not be used on pile fabric, e.g. velvet, as they will destroy the fabric's natural feel.
The printing of fabrics with opaque pigments that lie on the surface of the fabric instead of being absorbed into the fibres. Such pigments should not be used on pile fabric, e.g. velvet, as they will destroy the fabric's natural feel.
Pile,
A plush or shaggy surface on a fabric resulting from loops or ends of yarn or fiber projecting above or below the surface of the fabric. In Oriental carpets, pile is formed by the cut ends of yarns commonly called rug knots.
A plush or shaggy surface on a fabric resulting from loops or ends of yarn or fiber projecting above or below the surface of the fabric. In Oriental carpets, pile is formed by the cut ends of yarns commonly called rug knots.
Piled (steel),
A method of improving the mechanical properties of iron and steel, in which the metal is forged out, folded back on itself and the resulting ‘pile’ of metal is welded together. This process may be repeated several times so that the final metal consists of many fine layers. Piling was used to homogenise steel produced by carburising strips of iron. Because the carbon has to diffuse into the metal from the surface it is difficult to produce homogeneous steel of any great thickness. If carried out successfully the piling process reduces the final thickness of each original strip to a fine lamination, while migration of carbon at welding heat further homogenises the carbon content. Thus, although exactly the same methods are used as in damascening (forging, folding and welding) the results and aims are different. The aim was to produce a more uniform consistent structure, whereas, damascening through the use of two different types of iron or steel deliberately produces a decorative pattern. The aim of piling (although not always achieved) was to produce a macro- and microscopically homogeneous steel, whereas, the aim of damascening was to produce a steel that behaved in a uniform manner in the bulk, but was patterned on the small scale. The production of 'shear steel', the highest-quality British product before the development of crucible steel, was essentially a large-scale version of piling, though given the thickness of the blister steel bar raw material, micro-homogeneity could not be achieved (Barraclough 1984, 45-6 and 65-7). Although, it is absolutely clear that some artefacts have been made by this technique, it is likely that some that been identified as having been made by this technique are, in fact, the result of either fortuitous banding, or the side effect of other parts of the manufacturing process.
A method of improving the mechanical properties of iron and steel, in which the metal is forged out, folded back on itself and the resulting ‘pile’ of metal is welded together. This process may be repeated several times so that the final metal consists of many fine layers. Piling was used to homogenise steel produced by carburising strips of iron. Because the carbon has to diffuse into the metal from the surface it is difficult to produce homogeneous steel of any great thickness. If carried out successfully the piling process reduces the final thickness of each original strip to a fine lamination, while migration of carbon at welding heat further homogenises the carbon content. Thus, although exactly the same methods are used as in damascening (forging, folding and welding) the results and aims are different. The aim was to produce a more uniform consistent structure, whereas, damascening through the use of two different types of iron or steel deliberately produces a decorative pattern. The aim of piling (although not always achieved) was to produce a macro- and microscopically homogeneous steel, whereas, the aim of damascening was to produce a steel that behaved in a uniform manner in the bulk, but was patterned on the small scale. The production of 'shear steel', the highest-quality British product before the development of crucible steel, was essentially a large-scale version of piling, though given the thickness of the blister steel bar raw material, micro-homogeneity could not be achieved (Barraclough 1984, 45-6 and 65-7). Although, it is absolutely clear that some artefacts have been made by this technique, it is likely that some that been identified as having been made by this technique are, in fact, the result of either fortuitous banding, or the side effect of other parts of the manufacturing process.