Difference between revisions of "Guides/Scanning Cover Art"

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==== Sensor Type ====
 
==== Sensor Type ====
 
For best results, get a '''Charged-Coupled Device''' (CCD) scanner as opposed to a '''Contact Image Sensor''' (CIS) device. CCDs tend to capture better quality scans and have a much greater depth of field. CIS scanners blur anything that is not pushed right up to the screen, which would be a problem when scanning spines of booklets or anything not completely flat ([https://web.archive.org/web/20210505024619/http://www.microscopy-uk.org.uk/mag/artjan13/dw-scanner-type.html example]).
 
For best results, get a '''Charged-Coupled Device''' (CCD) scanner as opposed to a '''Contact Image Sensor''' (CIS) device. CCDs tend to capture better quality scans and have a much greater depth of field. CIS scanners blur anything that is not pushed right up to the screen, which would be a problem when scanning spines of booklets or anything not completely flat ([https://web.archive.org/web/20210505024619/http://www.microscopy-uk.org.uk/mag/artjan13/dw-scanner-type.html example]).
  +
   
 
This is not to say CCD scanners always look better than CIS. For example, the CIS scanner, Canon PIXMA MG3220, creates raw scans with more vibrant and accurate colors than the more expensive CCD, Plustek OpticPro A320L. To get comparable color quality, the colors of the CCD’s raw scan need to be adjusted based on the scanner’s calibration, then the brightness levels adjusted. After this the CCD scan is superior since everything is in focus and has more detail for the intended resolution.
 
This is not to say CCD scanners always look better than CIS. For example, the CIS scanner, Canon PIXMA MG3220, creates raw scans with more vibrant and accurate colors than the more expensive CCD, Plustek OpticPro A320L. To get comparable color quality, the colors of the CCD’s raw scan need to be adjusted based on the scanner’s calibration, then the brightness levels adjusted. After this the CCD scan is superior since everything is in focus and has more detail for the intended resolution.

Revision as of 17:30, 3 October 2022

How to Make High Quality Scans of Music Artwork

Version MB-0.1.1-20220518

Layout

This guide is divided into two parts: one on scanning and one on digitally processing scans. The first part is mostly complete, but the digital processing part needs refining with current techniques from the community. It should still be helpful in its current form to anyone wanting to scan CD and vinyl artwork for inclusion in MusicBrainz' Cover Art sections.

Overview

Digitizing artwork can be simple and easy, but it can also be slow and tedious if you plan to remove as many imperfections as possible. This guide explains in detail how you get the best quality scans without spending too much time with diminishing returns. It’s unreasonable to expect everyone to spend hours removing every speck of dust or share gigantic files, so automation is used where possible and lossy compression where it makes sense. I hope you can use this guide as a reference whether you are scanning record covers, CD fronts, booklets, or discs.

The basic workflow for scanning is to:

  • Scan
  • Rotate
  • Deskew
  • Crop
  • Straighten text
  • Color correct
  • Descreen
  • Clean up
  • Create JPG

Not necessarily in that exact order. You may not need to do all these steps, or you may need to do more.


Notes on this guide:

  1. With respect to your time, we try to condense as much relevant information as possible into step-by-step sections without being too wordy. Currently, there are several sections that could use step-by-step guides that don’t have them, but more are planned with instructions in the future.
  2. This guide is not limited to free software since we try to recommend the best possible tools, free or not.
  3. Focus on Windows compatible software, but Mac and Linux alternatives are mentioned where appropriate.

A step-by-step approach is used in lieu of oversimplification to avoid confusion for beginners. Discussion and feedback thread available here:

Part One: Digitizing

Converting a cover to a digital image is best done with a flatbed scanner (preferred) or a camera setup. Paper-fed scanners should be avoided.

Scanners

Size

The size of the scanner is important to consider if you want to capture record covers in one pass. If you want to scan LP covers, a 12″×17″ scanner will work better than an 11.69″×17″ scanner but still usually leaves off part of an edge (LP covers are 12.375″ squares), a camera setup can be used to photograph the LP cover.

Dimensions of standard paper sizes and scanners. Numbers in bold are exact, and numbers not bolded are rounded. *Scanner pixel density is typically measured in pixels per inch, which makes it difficult to comply with a millimeter standard.5.
Dimensions of standard paper sizes and scanners. Numbers in bold are exact, non-bold numbers are rounded.*Scanner pixel density is typically measured in pixels per inch (PPI), please prefer to select scanner models by PPI.

Sensor Type

For best results, get a Charged-Coupled Device (CCD) scanner as opposed to a Contact Image Sensor (CIS) device. CCDs tend to capture better quality scans and have a much greater depth of field. CIS scanners blur anything that is not pushed right up to the screen, which would be a problem when scanning spines of booklets or anything not completely flat (example).


This is not to say CCD scanners always look better than CIS. For example, the CIS scanner, Canon PIXMA MG3220, creates raw scans with more vibrant and accurate colors than the more expensive CCD, Plustek OpticPro A320L. To get comparable color quality, the colors of the CCD’s raw scan need to be adjusted based on the scanner’s calibration, then the brightness levels adjusted. After this the CCD scan is superior since everything is in focus and has more detail for the intended resolution.

Resolution

The scanner should have an optical sensor reading minimum of at least 1,200 dpi and this is real resolution. In labeling this is the smaller number and any larger numbers are the interpolated resolution done by software (can ignore). Further reading.

First number: maximum real resolution vs. second number of enhanced resolution read by software.


If a scanner’s specifications state two DPIs, such as 4,800 x 9,600 dpi, then the smaller number is the resolution of the scanning sensor and the larger is the precision of the stepper motor moving the sensor. If you choose to scan at a resolution that is not a factor of the stepper motor dpi then some location error will occur (explained). Your scanner might avoid this error if it scans at the next highest compatible stepping size and reduces the image dimensions in software.


Best is to scan at the highest allowable dpi then move onto post-processing in image editing software.

Other Factors to Consider in Scanners

  • A book-edge, where the scanning surface reaches all the way to the edge of the scanner. This is useful so you can scan half a booklet without removing the staple and while keeping the page flat against the glass. Sometimes the glass surface does not reach the edge but is the same height as the side, which helps keep the page flat on the glass
  • Removable cover for scanning large things
  • Buttons on the scanner are not important. These buttons usually only work with the inferior default scanning software
  • Speed of scanning
  • Color depth
  • An infrared channel that can be used to digitally remove dust and scratches
Zoomed-in example of dust on scanning sensors with a green stripe on the left-hand side, a red stripe just right of the “1,” and another green stripe on the far right-hand side off cover.


In terms of maintenance, keep around a microfiber cloth and air-blower to remove glass dust. Canned air might spray propellant onto the glass, so make sure to use something that’s meant for lenses such as the Giottos Rocket Blaster. Use a small amount of glass cleaner or 99% isopropyl alcohol on an eyeglass microfiber cloth to remove anything that can’t be blown off. PEC-PADs are disposable wipes that are helpful in cleaning glass without introducing more lint or dust.


Keep an eye out for faint, vertical, colored lines in your scans. This is the result of dust infiltrating your scanner and latching onto the sensors. It is usually possible to disassemble the scanner with simple tools and blow or wipe the dust away, but take care not to introduce additional dust.

Recommended Scanner Models

Plustek OpticPro A320L (2017) - $600

  • 24-bit color output
  • Up to 1600 dpi
  • 12″ x 17″

Part One: Summary