Bio-Rad eBook - 2019 - 13

Film vs. Digital Imaging for Western Blotting
Advantages of Digital Imaging Systems

Photographic film has long been used for radiolabeled and visible light imaging in southern and western blotting,
with one of its main virtues being sensitivity. Almost any signal can be captured with a sufficiently long exposure.
Film use, however, comes with significant drawbacks: the time and cost of film development and waste disposal,
the limited dynamic range of film imaging, and difficulty of acquiring quantitative data using film.
Digital imaging systems eliminate these disadvantages and deliver very fast results with simpler imaging
techniques. Furthermore, integrated software makes data acquisition and analysis much easier, particularly
quantitation. With the digital revolution in consumer photography, advanced digital imaging systems for the lab
have greatly improved. Digital sensitivity now equals or exceeds film, and the broad dynamic range enabled
by digital imaging systems allows for accurate quantitation of a range of signal intensities, along with other
advantages over film.
Key Benefits of Digital Imaging Systems:
* Wide dynamic range ≥ 4 logs
* Quantitative
* Digital documentation
* Environmentally friendly-no chemicals!
* No costly consumables (film)
* Initial capital investment typically recovered in as little as 1 year

Digital Imaging for Quantitative
Western Blotting
The reliable quantitation of digital imaging systems
makes them the best choice for a quantitative blot assay.
Normalizing blots with housekeeping proteins (HKPs)
presents problems with HKP expression variability and
measurement linearity, especially in the mismatch between
typically highly expressed HKPs and target proteins. Total
protein normalization using Stain-Free Imaging allows
normalization over a wide dynamic range.
As the integrity of quantitative blot data has been
increasingly called into question, journals have begun
revising their publication standards for this data. The use
of X-ray film has been specifically cited for its low dynamic
range, leading to saturation problems. A stain-free enabled
digital imaging system enables you to consistently get
publication-quality data.

New Publication
Requirements
"Housekeeping
proteins should not be
used for normalization
without evidence
that experimental
manipulations do not
affect their expression."
Revised guidelines for authors from

Journal of Biological Chemistry

jbcresources.asbmb.org/collectingand-presenting-data

Advantages of Digital Imaging Over Film
bio-rad.com/DigitalWestern

http://jbcresources.asbmb.org/collecting-and-presenting-data http://jbcresources.asbmb.org/collecting-and-presenting-data http://www.bio-rad.com/DigitalWestern http://www.bio-rad.com/DigitalWestern http://www.bio-rad.com/DigitalWestern http://www.bio-rad.com/DigitalWestern

Bio-Rad eBook - 2019

Table of Contents for the Digital Edition of Bio-Rad eBook - 2019