Stock, Laid and Wove

Stock

• Basis Weight
  The basis weight of a paper is the designated fixed weight of 500 sheets,
  measured in pounds, in that paper's basic sheet size.
  It is important to note that the "basic sheet size" is not the same
  for all types of paper.
• Caliper
  Caliper refers to the thickness of a sheet of paper expressed
  in thousandth of an inch. This measurement is taken with a micro meter.
  Normally, paper caliper should not have more than a + or - 5% variance
  within a sheet. Generally, the relation between caliper and basis weight ....
  the greater the caliper (the thicker the paper), the greater the paper weight.
• Equivalent Weight
  While different paper types have different basic sizes,
  papers can still be compared by using equivalent weight.

Weight and thickness equivalents for paper stocks

Bond Lbs	Offset Lbs	Cover Lbs	Tag Lbs	Index Lbs	Points	Thickness (inches)
16	40	22	37	33	3.2	.0032
18	45	24	41	37	3.6	.0036
20	50	28	46	42	3.8	.0038
24	60	33	56	50	4.8	.0048
28	70	39	64	58	5.8	.0058
29	73	40	62	60	6	.0060
31	81	45	73	66	6.1	.0061
35	90	48	80	74	6.2	.0062
36	90	50	82	75	6.8	.0068
39	100	54	90	81	7.2	.0072
40	100	56	93	83	7.3	.0073
43	110	60	100	90	7.4	.0074
44	110	61	102	92	7.6	.0076
47	120	65	108	97	8	.0078
53	135	74	122	110	9	.0085
54	137	75	125	113	9	.009
58	146	80	134	120	9.5	.0092
65	165	90	150	135	10	.0095
67	170	93	156	140	10.5	.010
72	183	100	166	150	11	.011
76	192	105	175	158	13	.013
82	208	114	189	170	14	.014
87	220	120	200	180	15	.015
105	267	146	244	220	18	.0175

http://www.paper-paper.com/weight.html

Wove 

Wove paper is a writing paper with a uniform surface, not ribbed or watermarked. The papermaking mould's wires run parallel to each other to produce laid paper, but they are woven together into a fine wire mesh for wove paper. The originator of this new papermaking technique was James Whatman (1702–59) from Kent, England.

For 500 years European paper makers could only produce what came to be called laid paper. In 1757 John Baskerville printed his famous edition of Virgil on a new kind of paper, called Wove (known in Europe as Vélin). This paper is now known to have been made by the elder James Whatman. Twenty-five years later (1780s) the manufacture of wove paper spread quickly to other paper mills in England, and was also being developed in France and America. All this took place over a decade before a machine to replace making paper by hand was conceived. With the establishment of the paper machine (1807), the manufacture of paper on a wove wire base never looked back. Today more than 99% of the world's paper is made in this way.

Laid 

Laid paper is a type of paper having a ribbed texture imparted by the manufacturing process. In the 19th century its use diminished as it was largely supplanted by wove paper. Laid paper is still commonly used by artists as a support for charcoal drawings.

In pre-mechanical papermaking (from the 12th century into the 19th century), the laid pattern was produced by the wire sieve in the rectangular mold used to produce single sheets of paper. A worker would dip the mold into a vat containing diluted linen pulp, then lift it out, tilt it to spread the pulp evenly over the sieve, and, as the water drained out between the wires, shake the mold to lock the fibers together. In the process, the pattern of the wires in the sieve was imparted to the sheet of paper.

Modern papermaking techniques use a dandy roll to create the laid pattern during the early stages of manufacture, in the same way as applying a paper watermark. While in the wet state, the paper stock (a dilute dispersion of the cellulose fibers in water) is drained on a wire mesh to de-water the stock. During this process, a dandy roll with a laid mesh pattern is pressed into the wet stock, displacing the cellulose fibre. This pattern has to be applied at a particular stock consistency; otherwise the pattern will be lost as the fiber flows back while the stock moves past the dandy (too wet), or fiber will pick out of the stock (too dry), causing surface disruption. As the fiber is displaced, localized areas of higher and lower density are produced in a laid pattern, and the pattern is also created on the paper's surface. The pattern is therefore apparent both as one looks through the sheet and as one views its surface. Applying the laid pattern as a mechanical emboss would not create the laid pattern effect on the look-through, as this is only achieved by watermarking techniques.

http://www.wikipedia.org/