Deciding whether to use PNG or not

There are many fantastic points and examples in this essay by Phillip Hoyt. One of the most unique items he brings up is the file type’s abilities with regards to Gamma Correction.

“From the LibPNG site: “Gamma correction basically refers to the ability to correct for differences in how computers (and especially computer monitors) interpret color values.” There are two factors here: the ability to predict what an image, say a photograph, will look like on another monitor; and the ability to match the colours from different sources on a single page. Predicting what an image will look like is a laudable goal, but unrealistic for me to explore here since it requires seeing the same image on two different computers side-by-side. I can, however, compare html/css colours to image colours. Ideally, a colour which Photoshop (or your graphics application of choice) calls BF2026 should be indistiguishable from the same colour embedded in a web page.

For this test I cut the same graphic down the middle and placed bars of the same colour (by hex code) beside the image for comparison. I tested on graphics created in both the GIMP and in Photoshop with upredicatable results.

The GIFs matched the html colours on all machines and browsers that I tested. There were only two cases that I found where the PNGs matched the html colours — the Photoshop PNG in Apple’s new Safari browser, and the GIMP PNG in Mozilla.”

Read the full article hosted by evolt.org.