Some music records are pressed on coloured vinyl or with paper pictures embedded in them ("picture discs"). These discs can become collectors' items in some cases. Certain 45-rpm RCA or RCA Victor "Red Seal" records used red translucent vinyl for extra "Red Seal" effect. During the 1980s there was a trend for releasing singles on coloured vinyl — sometimes with large inserts that could be used as posters. This trend has been revived recently and has succeeded in keeping 7" singles a viable format.
Vinyl music record standards for the United States follow the guidelines of the Recording Industry Association of America (RIAA). The inch dimensions are nominal, not precise diameters. The actual dimension of a 12 inch record is 302 mm (11.89 in), for a 10 inch it is 250 mm (9.84 in), and for a 7 inch it is 175 mm (6.89 in).
Records made in other countries are standardized by different organizations, but are very similar in size. The record diameters are typically 300 mm, 250 mm and 175 mm.
There is an area about 6 mm (0.25?) wide at the outer edge of the disk, called the lead-in where the groove is widely spaced and silent. This section allows the stylus to be dropped at the start of the record groove, without damaging the recorded section of the groove.
Between each track on the recorded section of an LP record, there is usually a short gap of around 1 mm (0.04") where the groove is widely spaced. This space is clearly visible, making it easy to find a particular track.
Towards the label centre, at the end of the groove, there is another wide-pitched section known as the lead-out. At the very end of this section, the groove joins itself to form a complete circle, called the lock groove; when the stylus reaches this point, it circles repeatedly until lifted from the record. On some recordings (for example Spice by Eon), the sound continues on the lock groove, which gives a strange repeating effect. Automatic turntables rely on the position or angular velocity of the arm, as it reaches these more widely spaced grooves, to trigger a mechanism that raises the arm and moves it out of the way of the record.
The catalog number and stamper ID is written or stamped in the space between the groove in the lead-out on the master disc, resulting in visible recessed writing on the final version of a record. Sometimes the cutting engineer might add handwritten comments or their signature, if they are particularly pleased with the quality of the cut.