#3. If you’re reading this, it’s not too late: how to get image data of appropriate quality and resolution
This post is part of a weekly series about image screening. All published posts can be found on this page.
The key to high-quality figures is high-quality data capture. Figure-making settings are important, but so are the settings used during digital capture and storage of images. As discussed previously, it sometimes happens that pieces of image data in a figure are not of sufficient quality to allow our routine figure-screening process. Researchers should therefore carefully consider the resolution settings when first acquiring and storing their data. Western blot and gel images in particular are a contentious subject, but they do not have to be! Here are some easy ways to resolve (and hopefully prevent) any issue you might encounter during a journal’s figure check.
Whether you are using films or a digital imager, there are two crucial steps to pay close attention to: scanning and exporting. It is very important to do both at the highest resolution available to you (minimally 300 dpi) and to make sure that no pixel averaging is enabled by default (more on that in the next paragraph). This likely means you will have to explore and adjust the system’s settings at the time of first use so as to ensure scanning and exporting generates images at 300 dpi. If the resolution setting is not easily identifiable or seems as though 72 dpi is your only choice, we recommend calling a service representative, your IT department (or even us and we’ll try our best to help).
In addition to choosing the appropriate resolution, you must check that no averaging is enabled during scanning or exporting. “Pixel averaging” is a common way of reducing noise and file size in image processing. What this process does is apply an algorithm that “averages” a group of pixels to produce “larger” new pixels and will result in fewer pixels overall. In other words, each new pixel is a function of an area of pixels. This process implies that you are losing some of the information that the original, “smaller” pixels present in the image encoded. That is why, although you may want to play with it for your next Instagram art project, pixel averaging should be avoided for all image data.
Lastly, when exporting, it is important to export to a loss-less file type such as TIFF, and avoid JPEGs at all cost – more details to come in next week’s installment.