Text over image contrast checker

1. How do I check the contrast of an image?
2. Is text over image accessible?
3. What is a 4 5 1 contrast ratio?

How do I check the contrast of an image?

Contrast is defined as the difference between the highest and lowest intensity value of the image. So you can easily calculate it from the respective histogram. Example: If you have a plain white image, the lowest and highest value are both 255, thus the contrast is 255-255=0.

Is text over image accessible?

The Web Content Accessibility Guidelines (WCAG) recommend avoiding using images of text if you expect the text to be read by the user, unless it's necessary such as in a logo or brand name, in which case the alt text should be the same as the text in the image.

What is a 4 5 1 contrast ratio?

The 4.5:1 ratio is used in this provision to account for the loss in contrast that results from moderately low visual acuity, congenital or acquired color deficiencies, or the loss of contrast sensitivity that typically accompanies aging.