Pre-acceptance Test Roll Scans

This page links to sample scans of various roll types from the Stanford Library piano-roll collections, mostly from the 8000-roll Condon collection. Click on roll thumbnail images in the list below to view more information about each roll as well as links to the original scans and analyses of the scans. Note that the original full-color uncompressed TIFFs are 1–6 GB.

Rolls are grouped by format. Click on a format in the list below to move to the rolls for that format.

To see detailed information about a roll, click on its icon in the list. Note that the "Automatic analysis of scan" link at the bottom of most roll entries gives a detailed, automatically generated analysis of the scan.

Here is a spreadsheet summary of the analysis:

Frame duplications

16 of the roll scans contain frame-duplication errors caused by an earlier version of the scanning software (and camera driver), where pieces of the images are duplicated and over-write frames missing or dropped when recording the images. Consecutive frame-duplication errors are marked in the reduced JPEG images, but not in the original TIFF. The marks consist of a solid color covering 1/4 of the problemmatic frame. For each adjacent frame, the duplication marker shifts to the other side of the image. Here is an example from the Pennino roll where there are 10 successive duplicate frames (representing 1 physical inch on the rolls):

Most commonly there will be a burst of shorter dupliciation errors at the start of a scan, such as this example from the same roll:

Three colors are cycled through to mark the frame duplications to separate separate duplcation of a different frame, so the above image contains six separate duplication events, each two to three frames in length. Scans from December 2017 and later do not (should not) have duplication errors since the scanning software will abort scanning if any are detected.

Ampico Rolls

Ampico rolls were produced starting in 1913 and are the other most common American roll type. Click on the roll thumbnails below to view more information about each roll.

Duo-Art Rolls

Duo-Art rolls were produced by the Aeolean Company, which was one of the two dominant player-piano companies in the United States. Click on the roll thumbnails below to view more information about each roll.

Green Welte Rolls

"Green roll" are usually green-hue Welte-Mignon rolls produced from 1922 to 1932 in Freiburg, Germany by Welte & Sons. They have 98 rows of holes spaced 9 per inch, and a width of 11.25 inches. Click on the roll thumbnails below to view more information about each roll.

Welte-Mignon Licensee Rolls

Licensee rolls are mostly Welte rolls for the American market. Click on the roll thumbnails below to view more information about each roll.

Red Welte Rolls

"Red rolls" are usually red-colored Welte-Mignon rolls produced by Welte & Sons. They invented paper rolls for playing organs in the 1880's, and they were the first company to record live piano performances, starting in 1904 on these red rolls. Red rolls were produced in Germany from 1905 to 1932, and in Poughkeepsie, New York from 1913 to 1920. New York rolls sometimes have a cloth leader. They have 100 rows of holes at 8 holes per inch, with the width of the roll being about 12.9 inches. Click on the roll thumbnails below to view more information about each roll.

Metrostyle Rolls

These are non-reproducing rolls that have tempo and dynamics curves printed onto the rolls. Click on the roll thumbnails below to view more information about each roll.

Organ Rolls

Duo-Art 176-note organ rolls (two offset tracker bars). Stanford Libraries has a collection of 2000 Duo-Art organ rolls. Click on the roll thumbnails below to view more information about each roll.

QRS Rolls

Rolls from the QRS company. Click on the roll thumbnails below to view more information about each roll.

Non-reproducing Rolls

This are rolls which are not recording a live pianist. Click on the roll thumbnails below to view more information about each roll.

Calibration Roll

This section contains scans of a roll used to calibrate the horizontal and vertical DPI at the lower and upper camera setting. The lengthwise DPI was measured to be 300.24±0.21 for the lower camera setting and 300.32±0.19 in the upper camera setting. The camera position should not affect the lengthwise DPI, and it doesn't. The width DPI was measured to be 301.39 pixels/inch for the lower camera setting and 251.48 pixels/inch for the upper camera setting. The calcuations for these values are on this spreadsheet.